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Photosynthate remobilization capacity from drought-adapted common bean (Phaseolus vulgaris L.) lines can improve yield potential of interspecific populations within the secondary gene pool

  • Institute for Organic Food and Farming

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Interspecific lines obtained from crosses between common bean (Phaseolus vulgaris L.) and other species from its secondary gene pool have a tendency for excessive vegetative growth and low grain yield. Contrariwise, drought-adapted common bean lines have been observed to produce high yields despite low shoot biomass production. This was attributed to greater remobilization of photosynthates to grain development. The objective of the present study was to investigate whether F2-families derived from crosses between an interspecific line and drought-adapted P. vulgaris lines have improved ability to remobilize greater proportion of photosynthate from shoot biomass to grain yield and subsequently obtain higher yield potential. Seven F2-progenies derived from crosses of an interspecific hybrid line of P. vulgaris × Phaseolus dumosus with seven drought-adapted lines reflecting a range of photosynthate remobilization and partitioning were evaluated under irrigated and rainfed field conditions along with their eight parent lines and one drought-tolerant check at the International Center of Tropical Agriculture (CIAT) at Palmira, Colombia. Although no single parent trait led to higher yield potential in progenies, the mean yield potential of the progenies, as well as mean yield under drought was significantly higher than yields of the interspecific parent, indicating that crosses with drought-adapted bean lines with greater plant efficiency constitute a promising breeding approach for yield improvement of interspecific crosses in both drought stressed and favorable environments
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Journal of Plant Breeding and Crop Science Vol. 4(4), pp. 49-61, 29 February, 2012
Available online at
DOI: 10.5897/JPBCS11.087
ISSN 2006-9758 ©2012 Academic Journals
Full Length Research Paper
Photosynthate remobilization capacity from drought-
adapted common bean (Phaseolus vulgaris L.) lines
can improve yield potential of interspecific populations
within the secondary gene pool
Stephanie M. Klaedtke1,2, Cesar Cajiao1, Miguel Grajales1, José Polanía1, Gonzalo Borrero1,
Alberto Guerrero1, Mariela Rivera1, Idupulapati Rao1, Stephen E. Beebe1* and Jens Léon2
1Centro Internacional de Agricultura Tropical (CIAT), A. A. 6713, Cali, Colombia.
2Institute of Crop Science and Resource Conservation, Crop Genetics and Biotechnology Unit, University of Bonn,
Katzenburgweg 5, 53115 Bonn, Germany.
Accepted 27 February, 2012
Interspecific lines obtained from crosses between common bean (Phaseolus vulgaris L.) and other
species from its secondary gene pool have a tendency for excessive vegetative growth and low grain
yield. Contrariwise, drought-adapted common bean lines have been observed to produce high yields
despite low shoot biomass production. This was attributed to greater remobilization of photosynthates
to grain development. The objective of the present study was to investigate whether F2-families derived
from crosses between an interspecific line and drought-adapted P. vulgaris lines have improved ability
to remobilize greater proportion of photosynthate from shoot biomass to grain yield and subsequently
obtain higher yield potential. Seven F2-progenies derived from crosses of an interspecific hybrid line of
P. vulgaris × Phaseolus dumosus with seven drought-adapted lines reflecting a range of
photosynthate remobilization and partitioning were evaluated under irrigated and rainfed field
conditions along with their eight parent lines and one drought-tolerant check at the International
Center of Tropical Agriculture (CIAT) at Palmira, Colombia. Although no single parent trait led to higher
yield potential in progenies, the mean yield potential of the progenies, as well as mean yield under
drought was significantly higher than yields of the interspecific parent, indicating that crosses with
drought-adapted bean lines with greater plant efficiency constitute a promising breeding approach for
yield improvement of interspecific crosses in both drought stressed and favorable environments.
Key words: Drought adaptation, interspecific crosses, dry matter partitioning, Phaseolus, remobilization, yield.
“It is not always easy to distinguish between wild and
cultivated plants in South America, for there are many
intermediate stages between the utilization of plants in
their wild state and their true cultivation”, noted the
ethnologist and anthropologist Claude Lévi-Strauss in
1950 (Smithsonian Institution Bureau of American
Ethnology, 1950). Even today this is true for common
*Corresponding author. E-mail:
bean (Phaseolus vulgaris L.) and the species from its
secondary gene pool (Harlan and de Wet, 1971).
Cultivated P. vulgaris seems to have inherited survival
mechanisms from its wild ancestor expressed as
excessive viney growth and a lack of clear transition
between the vegetative and reproductive growth stages,
leading to a suppression of reproductive growth under a
range of environments and a poor response to favorable
conditions (Kelly et al., 1999; Beebe et al., 2008, 2009;
Butare et al., 2011). Analogous growth habits, with low
harvest indices (HI) and suboptimal yields are also
50 J. Plant Breed. Crop Sci.
adopted by species within common bean‟s secondary
gene pool such as wild and cultivated forms of Phaseolus
coccineus L. and Phaseolus dumosus Macfady and wild
Phaseolus costaricensis Freytag and Debouck (Debouck,
1999; Singh, 2001). Nevertheless, common bean is the
world‟s most important grain legume for direct human
consumption (Broughton et al., 2003), with 20.3 million
tons of dry bean harvested from 27.9 million ha
worldwide in 2008 (FAOSTAT, 2010). Almost 80% of dry
bean (P. vulgaris) is produced by small landholders in the
developing countries of tropical Latin America and Africa
(Rao, 2001), particularly in eastern and southern Africa
and Central America. In these regions, beans constitute
an important source of plant protein and micronutrients in
human diets (Broughton et al., 2003).
Common bean is often grown on marginal lands under
unfavorable environmental conditions (Rao, 2001;
Broughton et al., 2003) with minimal soil and crop
management inputs (Rao, 2001; Beebe et al., 2008, 2009).
Low soil fertility due to phosphorus (P) deficiency or
aluminum (Al) toxicity (Beebe et al., 2009) and high risk
of intermittent or terminal drought (White and Izquierdo,
1991; Muñoz-Perea et al., 2006) are among the most
common abiotic stresses. These production constraints
explain why average yields in many countries of Africa
and Latin America did not exceed 700 kg/ha in 2008
(FAOSTAT, 2010), although experimental dry bean yield
potential exceeds 3000 kg/ha (Beebe et al., 2006).
Regarding breeding efforts to improve grain yields, it has
been estimated that up to 90% of genetic variability in
common bean and its sister species remains un- or
underutilized (Singh, 2001). Therefore, species in the
secondary gene pool are considered easily accessible
potential sources not only for tolerance to abiotic
stresses, but also for agronomic and nutritional traits:
Year-long bean (P. dumosus) and scarlet runner bean (P.
coccineus) have been identified as sources of resistance
to important fungal pathogens (Singh, 2001) and high
iron (Fe) and zinc (Zn) content in grain in common bean
(Beebe et al., 2006; CIAT, 2008). Scarlet runner bean
also features resistances to viral and bacterial pathogens
(Singh, 2001) and to damage caused by the bean fly
(Ophiomyia phaseoli Tryon) (Kornegay and Cardona,
1991), as well as tolerance to low temperatures (Singh,
2001) and Al toxicity in soils (Beebe et al., 2009). P.
costaricensis holds yet unutilized potential for common
bean breeding (Singh et al., 1997). In fact, breeding
programs have mainly concentrated on P. coccineus
cultigens for gene introgression and the development of
advanced lines with acceptable yield from interspecific
hybrids with the secondary gene pool, particularly with
wild forms has been limited (Debouck, 1999; Singh, 2001).
Difficulties to capitalize on variability in these sister
species are attributable to excessive vegetative growth
and poor partitioning of dry matter to grain which are
inherent to all of them. However, efficient development
patterns with a clear transition to reproductive growth
allowing for higher grain yields under both drought and
favorable environments have been observed in drought-
adapted bean lines (Beebe et al., 2008). This was
associated with greater plant efficiency and remobili-
zation of photosynthates to grain (Rao, 2001; Beebe et
al., 2006, 2008; Rao et al., 2007, 2009). However, such
remobilization capacity is needed in interspecific lines
within the secondary gene pool to capitalize on their
excessive vegetative growth under favorable conditions.
Therefore, the present study was conducted to assess
whether the photosynthate remobilization and the
subsequent yield potential, of an interspecific advanced
bean line resulting from a cross between P. vulgaris and
P. dumosus can be improved by crossing it with drought-
adapted bean lines possessing higher photosynthate
remobilization capacity. An expected outcome of this
study is to draw initial conclusions for the implementation
of respective crosses in breeding programs aiming for the
introgression of desirable traits from the secondary gene
pool into P. vulgaris.
Experimental site and meteorological conditions
The experiment was conducted during the dry season from June to
September 2009 at the main experimental station of the
International Center for Tropical Agriculture (CIAT) in Palmira,
Colombia, located at latitude 29‟ N, longitude 76° 21‟ W and an
altitude of 965 m. The site has an average relative humidity of 74%,
896 mm of annual rainfall and an annual potential evaporation of
1834 mm. The soil is fine-silty, mixed, isohyperthermic Aquic
Hapludoll, having no major fertility problems (pH = 7.7). The trials
were managed according to standard practices to assure normal
growth of the crop (Beebe et al., 2010). During the crop growing
season, the mean maximum and minimum air temperatures were of
29.9 and 19.3°C in June, 32.2 and 19.1°C in July, 32.1 and 19.7°C
in August and 33.1 and 19.5°C in September, respectively. The
total potential pan evaporation of 574 mm during crop growth
exceeded total rainfall, amounting to 86 mm. With 21 mm of rainfall
in June, 8 mm in July, 29 mm in August and 28 mm in July, the
rainfall distribution pattern corresponded to terminal drought stress
conditions (Ludlow and Muchow, 1990).
Plant material
The interspecific [P. vulgaris × (P. vulgaris × P. dumosus)]
advanced inbred line MIB 755 was crossed with seven other
advanced inbred CIAT bean lines. MIB 755 was selected for high
Fe content in the grain from a backcross of an interspecific hybrid of
a Carioca-type common bean line (FEB 226) with a P. dumosus
accession, with FEB 226 as recurrent parent. Despite its valuable
Fe content, it lacks wide acceptance with farmers due to its viney
growth and low grain yields (S. Beebe, unpublished results),
according to the growth pattern described earlier. MIB 755 was a
suitable elite line to study the typical, viney growth pattern of
interspecific bean lines with the secondary gene pool and to use as
a common parent in further crosses for the study. The seven parent
lines crossed with MIB 755 resulted from breeding programs aiming
to produce drought-adapted beans from germplasm originating
from the Mesoamerican gene pool (Kwak and Gepts, 2009), but were
nevertheless chosen to test a range of productivity and
photosynthate remobilization capacity under rainfed conditions
based on earlier experience at CIAT. The only advanced line which
Klaedtke et al. 51
Table 1. Description of bean lines used as parents or as drought-resistant check.
Advanced line
Market class
Breeding objectives
MIB 755
High mineral content, particularly iron.
ALB 49
Tolerance to Al toxicity, some drought tolerance.
SEN 46
Drought adaptation.
SEN 74
Drought adaptation.
SER 155
Drought adaptation.
SER 16
Drought adaptation.
High iron content and drought tolerance.
SXB 743
Drought resistance.
SER 118
Drought resistance, associated with greater ability for remobilizing photosynthates.
had not resulted directly from a drought-breeding program was ALB
49, which was selected from a backcross of a scarlet runner bean
(P. coccineus) accession with SER 16, a drought-adapted line, also
used in the present study. A brief description of the advanced lines
used in crosses or as check (SER 118) is given in Table 1. In the
crosses with SEN 46, SER 16 and SXB 74, MIB 755 was employed
as female parent. In the crosses with ALB 49, SEN 74, SER 155
and SMR 4, MIB 755 was employed as male parent. Seven F1-
progenies resulted from these crosses. One F2-population was
derived from each F1-progeny by self-fertilization, resulting in seven
genetically segregating F2-progeny populations. These F2-
populations, the eight parent lines and one drought-resistant check
(SER 118) were included in the field trial, resulting in a total of 16
genotypes. All of these had indeterminate bush-type growth habits
with little climbing ability [(categories IIa to IIIa according to the
classification as described in van Schoonhoven and Pastor-
Corrales (1987)].
The CIAT advanced line SER 118 was used as drought-resistant
check having better dry matter partitioning ability to produce grain.
Later, the t erm „genotype‟ is used for the genetic materials included
in this study, be they homozygous advanced lines or F2-progenies.
For statistical analysis, genotype categories were formed. The term
drought-adapted parents further on designates the seven
advanced lines which represent a range of drought adaptation and
all were crossed with MIB 755 while progenies designate the F2-
populations resulting from these crosses.
Experimental design
Two field experiments were planted as 4 × 4 lattice designs with
three replications. The 16 genotypes were sown in six-row plots
with 60 cm between rows, using rows of 3.72 m long with a plant to
plant spacing of 7 cm within the row. The progeny of the cross
between MIB 755 and ALB 49 was an exception, as only four rows
of 1.86 m long were sown in each replication because of insufficient
seed that was harvested from the difficult cross between two
interspecific bean lines. The field with irrigated treatment received
eight gravity irrigations of 35 mm of water each during plant growth
to create favorable growth conditions. The field with drought
treatment was irrigated only twice for the establishment of the crop
and then left rainfed to create water-deficit conditions. In the
irrigated environment, two supplementary sowing dates were
needed to fill rows which dropped out because of technical
incidents. The second sowing date had six days of delay compared
to the first date. Rows sown on the third date were not used for
All samples for estimation of yields were taken from rows sown
on the first sowing date, while samples for physiological
measurements were taken from rows sown on the first or second
sowing date, when the plants reached the desired developmental
Yield measurements and phenological assessment
In the irrigated plots, grain was harvested from two rows (from an
average of 73.6 plants) after discarding end plants. In the rainfed
plots, grain was harvested from four rows (from an average of 174.2
plants) to compensate for spatial effects on plant growth. For the
progeny of the MIB 755 × ALB 49 cross, grain from only two rows
was harvested in both the irrigated and rainfed plots. Mean yields
per hectare were corrected for 14% moisture in grain. The drought
intensity index (DII) was calculated according to Fischer and Maurer
(1978). Days to flowering (DF) and days to physiological maturity
(DPM) were determined for each plot. DF is defined as the number
of days after planting until 50% of the plants have at least one open
flower. DPM is the number of days after planting until 50% of plants
have at least one pod losing its green pigmentation.
Assessment of leaf chlorophyll content, dry matter partitioning
and seed P concentration
Foliar greenness was measured from each leaflet of the youngest
fully expanded leaf of six plants in all plots by using a SPAD (soil
plant analysis development) chlorophyll meter (SPAD-502
Chlorophyll Meter, Minolta Camera Co., Ltd., Japan) at mid-pod
filling (MPF) (growth stage code 75 according to the BBCH scale for
beans) under irrigated and rainfed conditions. Dry matter
partitioning was assessed at MPF growth stage and also at harvest.
Plants growing in 1 m of row, chosen to be representative of the
growth on the respective plot were cut at the base. These samples
correspond to an area of 0.6 m2 and averaged 15 plants. Plants
were counted and separated into plant organs which were then
oven-dried for at least two days at 60°C and weighed. At MPF, dry
weights (DW) of leaves, stems and pods and reproductive
structures were determined. Leaf area was measured using a leaf
area meter (model LI-3000, LI-COR, NE, USA) and the leaf area
index (LAI) was calculated. At harvest, DW of stems, pod walls and
seeds, as well as the number of seeds were quantified. Pod
partitioning index (PPI), pod harvest index (PHI) and stem biomass
reduction (SBR) were calculated as defined previously (CIAT, 2009;
Beebe et al., 2010):
PPI (%) =
52 J. Plant Breed. Crop Sci.
PHI (%) =
SBR (%) =
Economic growth rate (EGR), that is, grain yield formed per day of
active plant growth up to physiological maturity was calculated
according to Ramirez-Vallejo and Kelly (1998). Whereas, PHI and
EGR were calculated for each genotype and replication and thus
underwent an ANOVA, PPI and SBR were calculated from means
of genotypes in the respective environment. Total seed P
concentrations were determined according to the procedures
described by Walinga et al. (1989).
Statistical analysis
One plot of ALB 49 was very heavily affected by Macrophomina
phaseolina and therefore was excluded from statistical analyses to
avoid inclusion of an unplanned diverging factor in the crop
environment caused by spatial differences in soil inoculum. Due to
missing data, the ANOVA could not be calculated for the planned
lattice design and was run as for a design of complete randomized
blocks, as suggested by Thomas (2006), by SAS generalized linear
model procedure (SAS Proc GLM), (SAS Insitute, 2004). Combined
analyses of drought and irrigated conditions were conducted with
replication, moisture treatment, genotype and genotype*moisture
treatment interaction as fixed factors. Separate analyses for
drought and irrigated conditions were conducted with replications,
genotypes, and a classification into the four genotype categories
„common parent‟ (that is, MIB 755), „drought-adapted parents‟ (that
is, ALB 49, SEN 46, SEN 74, SER 155, SER 16, SMR 4 and SXB
743), „progenies‟ (that is, the F2-populations resulting from the
crosses between the drought-adapted parents and the common
parent MIB 755) and „check‟ (that is, SER 118) on one hand and
genotypes among „drought-adapted parents and among progenies
on the other as factors. Least square means were generated and
pairwise differences analyzed by Tukey's range test, in the case of
equal sample sizes, or Tukey-Kramer method, for variables with
missing data. Honestly significant differences (HSD) were
computed for a level of probability of 5%. Differences between
genotype categories were estimated and tested using orthogonal
contrasts in the generalized linear model procedure. Pearson‟s
product-moment correlation coefficients and respective significance
levels were calculated using SAS Correlation procedure (SAS Proc
CORR). Traits of F2-prognies were regressed on traits of drought-
adapted parents using the SAS regression procedure (SAS Proc
In the following, values marked with *, ** or *** are statistically
significant at probability levels of 5, 1 and 0.1%, respectively.
Grain yields ranged between 1372 and 3364 kg/ha under
irrigated conditions and between 130 and 1928 kg/ha
under terminal drought (Table 2). The DII, reflecting
average yield reduction under drought, amounted to 0.57.
The drought-adapted parent SER 16 yielded highest in
both environments, out-yielding the drought-resistant
check. The interspecific lines MIB 755 and ALB 49 had
lowest yields. Although genotype-by-treatment interaction
for yield was non-significant (Table 3), the ranking of
genotypes according to yields differed between the two
environments when taking all genotypes into account and
when considering drought-adapted parents and progenies
separately. Nevertheless, yields under well-watered and
drought conditions were positively correlated. No geno-
type yielding more than the treatment mean under drought
stress yielded less than the mean under irrigation.
Although significant yield differences were found among
drought-adapted parents in both environments, none
were found among the progeny populations (Table 3).
The mean yield of progenies was, however, significantly
higher than that of the common interspecific parent
(Table 2). Significant differences were also found
concerning the time to flower and maturity. Progeny
populations flowered significantly earlier than the common
interspecific parent, but not as early as the mean value of
drought-adapted parents. Drought-adapted parents and
the drought-tolerant check matured earlier than the
interspecific parent and the progeny populations. On
average, the F2-populations matured significantly earlier
than their common interspecific parent under irrigated
conditions (Table 2). DF (Table 4) and DPM (Figure 1)
related negatively with yields regardless of moisture
treatments. The resulting EGR was highest for the
drought-resistant check and the mean of drought-adapted
parents in both environments. The mean EGR of progeny
populations was significantly higher than that of the
interspecific parent (Table 2). At MPF, no significant
differences in shoot biomass were found between geno-
types under irrigated conditions. Under drought, drought-
adapted parents and progeny populations produced
significantly more shoot biomass than the interspecific
MIB 755 and the check genotype (Table 2).
Regarding the values on dry matter distribution among
plant structures, the DW of vegetative plant organs at
MPF, that is, stems and leaves, did not significantly
correlate with grain yield in either of the two
environments, whereas the DW of pods did (rirrigation =
0.7**; rdrought = 0.83***). The following results were found
for LAI and SPAD chlorophyll meter readings (SCMR). As
for total shoot biomass DW, mean LAI at MPF was
significantly higher under irrigated conditions (3.38) than
under drought (2.35). In both environments, the progeny
populations produced the highest mean LAI values of
3.81 for irrigated and 2.54 for drought, differing
significantly from the mean value of 3.02 for drought-
adapted parents under irrigated conditions and from MIB
755 (1.74) and the check (2.01) under drought stress.
Mean SCMR at MPF were significantly higher under
drought (44.5) than under irrigation (42.5). Genotype ×
treatment interaction was significant. Under irrigation and
drought treatments, the mean SCMR of progenies (43.9
and 45.4, respectively) were significantly higher than for
drought adapted parents (41.4 and 44.0, respectively).
MIB 755 scored 44.1 and 43.6 under irrigation and
drought, respectively. Significant differences were found
Klaedtke et al. 53
Table 2. Least square means of yield (kg/ha), DF (d), DPM (d), EGR (kg/ha/d) shoot biomass DW at MPF (kg/ha), stem DW at harvest (kg/ha), PHI (%) and seed P concentration (%) and
respective honestly significant difference (HSD0.05) values under irrigated conditions (ir) and terminal drought stress conditions (td) for individual genotypes and the genotype categories
„drought-adapted parents‟ and „F2-progenies‟.
Stem DWharvest
Seed P conc.
MIB 755
SER 16
SXB 743
SEN 46
SEN 74
SER 155
ALB 49
MIB 755 x SER 16
MIB 755 x SXB 743
MIB 755 x SEN 46
SEN 74 x MIB 755
SMR 4 x MIB 755
SER 155 x MIB 755
ALB 49 x MIB 755
SER 118 (check)
Treatment mean ***
HSD0.05 genotypes
a, b, c, d Means within one column marked with different letters have statistically significant differences at a probability level of 5% . ***Differences between treatment means were statistically significant at a
probability level of 0.1% for all traits shown. Conc.: concentrations. ns: result was not statistically significant.
among drought-adapted parents and progenies
regardless of irrigated or drought stress treat-
ments. Under irrigation, SCMR readings at MPF
correlated negatively with grain yield (r = -0.65**)
and EGR (r = -0.77***). Among the plant
structures weighed at harvest, stem DW under
drought correlated negatively with grain yields
under drought (r = -0.67**) and irrigation (r = -0.56*).
The PHI of the common interspecific parent was
significantly lower than that of any other genotype
category, whereas the progeny mean was below
that of the drought-adapted parents and drought-
resistant check (Table 2).
Note that the common interspecific parent MIB
755 showed by far the lowest PPI (Figure 2) and
increased its shoot biomass DW between MPF
and harvest under drought, as reflected by a
negative SBR value (Figure 3). Under drought
conditions, positive correlations of SBR with PHI (r
= 0.65**) and PPI (r = 0.5*) were found while
correlations with seed P concentration (r = -0.58*)
and stem DW at harvest (r = -0.76***) were
negative. In the irrigated environment, SBR cor-
related positively with shoot biomass DW at MPF
(r = 0.56*) but negatively with PPI (r = -0.58*). The
mean P concentration in seeds at harvest was
significantly lower for the progeny populations
54 J. Plant Breed. Crop Sci.
Table 3. Degrees of freedom (DFr) and type I sums of squares of main effects for yield (kg/ha) and
days to physiological maturity (d) in the combined ANOVA of traits observed on 9 advanced bean
lines and 7 F2-progenies grown under irrigation and drought stress in Palmira, Colombia.
Sum of squares (Type I)
Genotype category
Among drought-adapted parents
Among progenies
Genotype x treatment interaction
Replication (within treatment)
* Statistically significant at a probability level of 5%.
Table 4. Correlation coefficients (r) between grain yield, DPM and P concentration in seeds and yield
components and biomass and partitioning traits observed on 9 advanced bean lines and 7 F2-progenies
grown under irrigation (ir) and terminal drought stress (td) in Palmira, Colombia.
Grain yield (kg/ha)
DPM (d)
Seed P conc. (%)
DF (d)
Seed P conc. (%)
Stem DWharvest (kg/ha)
PPI (%)
PHI (%)
SBR (%)
*, **, *** Statistical significance at a probability level of 5, 1 and 0.1%, respectively. conc.: concentration.
than for MIB 755 (Table 2). Yields were negatively
correlated with seed P concentration, as were partitioning
indices, regardless of irrigated or drought stress treat-
ments (Table 4). SBR correlated negatively with seed P
only under drought. Under irrigation, stem DW at harvest
correlated with seed P concentration. The partitioning
indices related more strongly with grain yield under
drought. PHI was among the traits most strongly related
with grain yields regardless of irrigated or drought stress
treatments. The relation of partitioning indices PPI and
PHI obtained under drought with grain yields produced
under irrigation is illustrated in Figure 2. Whereas, SBR
correlated with grain yield and early maturity under
drought, it did not under irrigation (Figure 3). The
regression analysis of grain yields and DPM of the F2
progenies under irrigated conditions on traits expressed
by their respective drought-adapted parent line under
drought and irrigated conditions revealed more parent
traits with an effect on the time to maturity than on yield
of progenies.
Regarding parent traits expressed under drought
stress, DF and LAI at MPF were related negatively with
progeny yield under irrigation (Table 5).
Significant differences between irrigated and drought
Klaedtke et al. 55
Figure 1. Days to physiological maturity (DPM) in days vs. grain yield (kg/ha) of nine advanced bean lines and seven F2-progenies
grown under A) irrigated conditions and B) under terminal drought stress in Palmira, Colombia. * indicates statistical significance at a
probability level of 5%.
Figure 2. Pod partitioning and pod harvest indices (%) of nine advanced bean lines and seven F2-progenies
under terminal drought stress vs. their grain yield (kg/ha) under irrigated conditions in Palmira, Colombia. ***
indicates statistical significance at a probability level of 0.1%.
stress treatments of overall means for grain yield,
phenological traits and total shoot biomass DW indicate
severe drought stress conditions in the rainfed crop. It
has been argued that DII values above 0.50 allow for
identification of high levels of drought resistance,
whereas genetic differences in germplasm may not result
in significant differences under very severe terminal
drought stress (Singh, 2007). Hence, the observed DII of
0.57 should permit the determination of genetic
differences of genotypes under severe terminal drought
in the rainfed environment. Grain yields obtained in the
favorable irrigated environment are considered as
reflecting yield potential of the respective genotype
(Beebe et al., 2008).
56 J. Plant Breed. Crop Sci.
Figure 3. Stem biomass reduction (%) vs. grain yield (kg/ha) of nine advanced bean lines and seven F2-progenies grown
under irrigated conditions and under terminal drought stress in Palmira, Colombia. *** indicates statistical significance at a
probability level of 0.1%; ns indicates that a result was not statistically significant.
Table 5. Regression coefficients (b1) and coefficients of determination (R2) of yield and DPM
of 7 F2-families irrigated conditions on selected traits expressed by the respective drought-
adapted parents.
Progenies, irrigated
Yield (kg/ha)
DPM (d)
Parent traits under drought
Yield (kg/ha)
EGR (kg/ha/d)
DF (d)
DPM (d)
Stem DWharvest (kg/ha)
PHI (%)
SBR (%)
Seed P conc.
Parent traits under irrigation
Yield (kg/ha)
EGR (kg/ha/d)
DF (d)
DPM (d)
Stem DWharvest (kg/ha)
PHI (%)
*, ** Statistical significance at a probability level of 5 and 1%, respectively. conc.: concentration.
The common interspecific parent
The common interspecific parent, MIB 755, presented
growth patterns differing markedly from the drought-
adapted common bean lines used in the trial. Low
photosynthate partitioning and subsequent remobilization
capacity, as reflected by low PPI and PHI under drought,
led to low grain yield under irrigation despite similar shoot
biomass production. High SCMR at MPF, reflecting high
chlorophyll content in leaves, also indicate excessive
vegetative growth and delayed senescence of leaves
inhibiting a clear transition to reproductive growth and
development. Consequently, maturity was reached more
than 10 days after the check and EGR was extremely
low. In fact, this poor response of MIB 755 to favorable
growth conditions led its mean grain yield to be
significantly lower than yields of the drought-resistant
check and all drought-adapted parents with the exception
of ALB 49, an interspecific line with P. coccineus.
Congruent growth tendencies were observed under
drought. Although total shoot biomass production was
lowest of all, it did not differ significantly from the drought
tolerant check. However, the mean yield of MIB 755
demonstrates a crop failure, whereas the check was
among the highest-yielding lines. Apart from extremely
poor dry matter partitioning towards grain yield, this is
explained by a negative SBR value. Even after the onset
of pod-filling, the MIB 755 crop continued storing of
photosynthates in stems instead of remobilizing them to
pods and seeds.
In conclusion, overlapping vegetative and reproductive
phases inherited from P. dumosus seem to hamper
drought-adaptation and also resulted in poor response to
favorable conditions as recorded in MIB 755.
Yields, phenology and economic growth rate
Acceleration of flowering and maturity have been
identified as important traits in adaptation of common
bean to terminal drought (White and Singh, 1991a;
Rosales-Serna et al., 2004), but early maturity has
generally been associated with lower yield potential in
favorable environments (White and Singh, 1991b).
Nevertheless, the correlation between irrigated grain yield
and DPM was significant and negative. Congruent
relationships were also found in interspecific RIL from
crosses of P. vulgaris with P.coccineus, leading to the
conclusion that traits inherited from P. coccineus may
have dominated and subsequently led to late maturity,
excessive vigor and inefficient partitioning of photo-
synthates to grain (Beebe et al., 2009), as observed in
the interspecific lines (ALB 49 and common parent MIB
755) and progeny populations when compared with the
drought-adapted common bean lines and the check. Two
reasons thus explain the negative correlation of DPM and
yield potential: Firstly, by simultaneous selection for grain
Klaedtke et al. 57
yield and early maturity (Wallace et al., 1993; Kelly et al.,
1999) under drought, breeders might have indirectly
selected for higher EGR in the drought-adapted lines.
Secondly, the inclusion of interspecific lines and
populations means that longer maturity in those
genotypes was attributed to excessive vegetative growth
and hence low EGR.
Photosynthate partitioning and remobilization
In both the drought and favorable environment, grain
yields correlated with pod DW, but not with DW of
vegetative plant structures, indicating that yields were
generally limited more by the capacity to partition dry
matter to reproductive growth than by lack of dry matter
accumulation. In view of the stronger reliance of grain
filling upon the remobilization of photosynthates within
the plant (Egli and Leggett, 1976), the variation of
photosynthate remobilization and partitioning capacity
may be expressed more clearly under drought. In
addition, the utilization of total shoot biomass at MPF for
the calculation of PPI can lead to an underestimation of
the maximal shoot biomass and overestimation of PPI for
some genotypes: the total shoot biomass DW of bush-
type bean crops commonly peak at the onset of rapid pod
growth, but some genotypes obtain their maximum
canopy DW near maturity (White and Izquierdo, 1991),
particularly under irrigation (Rosales-Serna et al., 2005).
For the interpretation of results, partitioning indices
obtained under terminal drought were thus assumed to
reflect the true potential of genotypes for photosynthate
partitioning to seed, particularly in the case of PPI. The
positive correlation of partitioning indices PHI and PPI
with yield under drought highlight the importance of both
steps of dry matter partitioning for yield production, that is
i) from vegetative biomass to pods, indicated by the PPI,
and ii) from pod wall to grain, indicated by the PHI. The
remobilization of photosynthates stored first in stems,
then in pod walls, to seeds has also been found to be
important for drought tolerance in Lupinus albus and
Lupinus mutabilis (Carvalho et al., 2004, 2005).
In the irrigated treatment, yield only directly correlated
with PHI. This does not contradict the importance of the
partitioning of photosynthates to pods, but indicates
yields were limited by poor allocation of dry matter to
seeds within pods rather than by pod formation. Beebe et
al. (2009) have found significant variability among bean
genotypes for mobilization of photosynthates from pod
walls to seeds and termed the failure to fulfill this very last
step of grain production as “lazy pod syndrome”. Of all
traits, PHI showed strongest correlations with yield
regardless of the irrigated or drought treatment.
Confirming its poor photosynthate remobilization
capacity, the PHI of MIB 755 was significantly below that
of any other genotype examined. Yield, partitioning
indices and EGR were negatively correlated with grain P
58 J. Plant Breed. Crop Sci.
concentration, suggesting that some genotypes utilize
acquired P more efficiently for grain production (Rao et
al., 2007). Yields related more strongly with low seed P
concentrations under drought than under irrigation. The
strong correlation of SBR values observed under drought
conditions with yields obtained under drought and
irrigated conditions indeed corroborates the importance
of the capacity to efficiently remobilize stem reserves to
pods for improving yield potential under favorable,
irrigated conditions as well as under drought conditions.
However, the physiological processes linked to this
remobilization seem to differ between plants grown under
drought stress and under favorable conditions. SBR
under irrigation and drought were in fact unrelated,
indicating that differences in stem reserve remobilization,
unlike other traits conducive to efficient reproductive
growth and earliness, were environmentally induced.
Under drought, SBR correlated negatively with seed P
concentration and stem DW at harvest and positively with
PHI and PPI. This indicates that superior performers
remobilize greater amounts of photosynthates from stems
to seed per unit amount of P mobilized to seed (CIAT,
2005, 2006). In contrast, under favorable conditions, SBR
correlated positively with shoot biomass DW at MPF and
negatively with PPI, suggesting that genotypes having
accumulated much dry matter in canopy, remobilized
more photosynthates from stems, but did not mobilize
them to pods. Such genotypes may have remobilized
photosynthates to leaves to favor vegetative growth
instead of making a clear transition to reproductive
growth. This was particularly observed for the common
interspecific parent and, to a lesser extent, the F2-
progenies. Although, there was no direct relation to yield,
stem DW at harvest correlated negatively with PHI and
positively with seed P concentration and DPM in the
favorable environment. No such correlations with PHI and
seed P concentration were observed for SBR in the
favorable environment. One may conclude that stem
reserve remobilization is a crucial stage of plant efficiency
for reproductive growth under drought, but it alone does
not ensure plant efficiency under favorable conditions. In
contrary, remobilized photosynthates in some cases
seem to be used for non-reproductive purposes such as
the maintenance of “stay-green” vegetative structures. In
fact, efficient partitioning and good response to favorable
conditions are associated with the ability to harness
vegetative growth independently of the ability to later
remobilize stem reserves, as indicated by low stem DW
at harvest.
Harnessing the vegetative growth may thus be related
with a clear transition from vegetative to reproductive
growth under favorable conditions.
The mean score of the progenies was between that of the
drought-adapted parents and the common interspecific
parent for most of the traits discussed. Under favorable
conditions, this was not obvious at first glance in the field,
as most progenies were actually more vigorous than MIB
755, as indicated by shoot biomass DW and LAI.
Nevertheless, mean stem DW of progenies at MPF and
harvest were below that of MIB 755, indicating that they
did not accumulate as much excessive stem reserves as
MIB 755. The significant negative relation of progeny
yields under irrigation with DF of respective parents, as
well as their stem DW at harvest under irrigation indicates
that parents having ability of harnessing vegetative
growth under favorable conditions and generally making
an early transition to reproductive growth resulted in
progenies with a better response to the favorable
environment. The LAI of parents under drought related
negatively with progeny yield potential, suggesting that
even under water-stress, some drought-adapted parents
were overly vigorous and passed on this trait to
progenies. However, yield differences among progenies
were non-significant. The selection of drought-adapted
parents with a range of remobilization and partitioning
capacities according to past experience was expected to
lead to a range in progeny yields. In fact, the PHI, which
correlated strongly with yields when including all geno-
types was similarly high for all drought-adapted parents in
this trial: Only SMR 4 and ALB 49 significantly differed
from other drought-adapted parents under irrigation and
no significant differences were found under drought.
Crossing MIB 755 with the drought-adapted parents
thus generally improved the dry matter partitioning within
pods in the progenies, but the limited range of PHI
represented did not allow for a strong differentiation
among progenies concerning this trait. On the other
hand, differences in plant efficiency of drought-adapted
parents in both environments were reflected in progenies
as earliness to mature under favorable conditions. Apart
from DPM of parents in both environments, traits
associated with efficient dry matter partitioning at all
levels under drought related with earliness of progenies
under favorable conditions. Early maturing progenies
were also produced by drought-adapted parents beginning
to senesce at MPF, as indicated by lower SCMR, and
having a strong capacity to remobilize photosynthates to
seeds within pods and produce high yields under
favorable conditions. Thus, those drought-adapted
parents that were able to counterbalance MIB 755‟s
excessive vegetative growth under favorable conditions
and “lazy pod syndrome” in both environments produced
more efficient progenies, although this efficiency was
expressed more by earliness than in grain yields. The
progeny of SER 16 stood out for its above-mean yields in
both environments, in line with the yields and the
remobilization and partitioning capacities of SER 16,
particularly concerning PHI. Except for ALB 49, it is the
only advanced line in the trial having race Durango
parentage, known for its rapid and complete transition to
reproductive growth with rapid seed filling and high HI
(Kelly et al., 1999). Race Durango germplasm has been
identified as an important source of drought resistance in
interracial crosses (Beebe et al., 2008; Porch et al.,
ALB 49 is a selection from an interspecific cross
including SER 16 as recurrent parent. Under irrigation, its
progeny yielded well above the best yielding parent. On
one hand, the significant result found in this particular
cross may be explained by the wide genetic distance
between parents, which resulted from interspecific
crosses with different Phaseolus species. On the other, it
may indicate that SER 16 produces efficient progenies
even when operating indirectly through offspring
containing SER 16 germplasm. The PPI and PHI of ALB
49 under drought were not high, but certainly acceptable
compared to the values obtained for MIB 755. The
comparatively high partitioning efficiency for an
interspecific bean line is attributable to the SER 16
parentage of ALB 49. The negative SBR values in both
environments constitute an inconsistent transition to the
reproductive phase inherited from the P. coccineus
parent, although overall vigor was low. Hence, the
combination of ALB 49 and MIB 755 germplasm entailed
the combination of acceptable dry matter partitioning with
vigor, leading to the compensation of reciprocal
unfavorable traits. Interestingly, SER 155 combined very
well with MIB 755 concerning yield potential, but poorly
regarding drought resistance, despite SER 155‟s
intermediate performance in both environments. The
parent‟s yield limitations under favorable conditions can
be explained by the extremely short growing cycle of
SER 155, restricting the genotype from producing high
grain yield despite high EGR. However, in its progeny, a
significantly longer duration of growth and maturity was
inherited from MIB 755, although it remained earliest to
mature among progenies. Combined with the highest PHI
and EGR among progenies, this led to the highest-
yielding progeny. As found for the progeny of ALB 49, it
seems that the combination SER 155 and MIB 755 led to
the compensation of reciprocal unfavorable traits for yield
potential. Low yields of the SER 155 progeny under
drought may be attributed to a shallow rooting system
inherited from SER 155, as detected on the parent in a
greenhouse trial.
In contrast, SMR 4 produced the lowest yielding
progeny. The shoot dry matter accumulation of the SMR
4 progeny was among the lowest under irrigation, but
above that of high-yielding drought-resistant check SER
118. So, vigor was not a limiting factor, but PHI below the
progeny mean indicates “lazy pod syndrome”. SMR 4
indeed had below average PHI and lacked seed filling in
the favorable environment as did MIB 755. Crossing the
two bean lines thus led to a similarly inefficient, low-
yielding progeny. Given their dry matter partitioning traits,
the black-seeded lines SEN 46 and SEN 74 combined
with interspecific MIB 755 in an unexpected manner.
Although the yield of the progeny of SEN 74 cor-
responded with the intermediate performance expected
Klaedtke et al. 59
from the intermediate remobilization and partitioning
capacity of SEN 74, the patterns of dry matter partitioning
within the progeny were quite different than that of SEN
74. Conversely, the progeny of SEN 74 had the lowest
PPI of all progenies under drought, although SEN 74
produced highest PPI. In contrast to the efficiency
observed in both the irrigated and drought environment
for the other black-seeded drought-adapted parent SEN
46, its progeny lacked efficiency to exploit the high
amount of dry matter accumulated in shoots despite very
high SBR. This progeny was, however, among the
earliest to mature under favorable conditions, again
indicating that plant efficiency inherited from drought-
adapted parents can be expressed more as earliness
than as yield potential in some progenies. On one hand,
SEN 46 and its progeny may indicate that high
remobilization and partitioning capacities as recorded by
high SBR and PHI values are not sufficient to
counterbalance inefficiencies inherited from MIB 755 in
progenies. On the other hand, the traits of progenies of
SEN 46 and SEN 74 with MIB 755 suggest that black-
seeded (SEN) lines do not combine well with MIB 755 as
do red-seeded (SER) lines.
Indeed, differences in combining abilities have been
found between the market classes. For example red-
seeded Mesoamerica lines have been found to combine
better with race Durango than black-seeded ones for
enhanced drought resistance (Beebe et al., 2008).
The results of the present study highlight problems that
are inherent in interspecific crosses of common bean with
its secondary gene pool. The evolution of species such
as P. dumosus or P. coccineus has favored a vigorous
vegetative growth at the expense of efficiency in grain
production. We have referred to the many attempts to
utilize these species to improve common beans,
especially as sources of disease resistance and in spite
of the number of attempts, very few common bean
cultivars carry genes derived from these species. We
suggest that the problems of poor photosynthate
remobilization that were documented in MIB 755 are
symptomatic of the poor quality of such interspecific
progenies. Using parents with enhanced photosynthate
remobilization capacity should be part of the strategy to
tap the vast genetic diversity of the secondary gene pool.
Under scenarios of climate change in which some
regions of the tropics are expected to receive significantly
more rainfall, these species may become more attractive
as sources of traits for humid environments, in which
case their use in breeding programs may be more
frequent (Beebe et al., 2011). For further investigation, it
is recommended that corresponding field trials be re-
peated with a higher number of drought-adapted parents
and various interspecific parents to verify relations found
60 J. Plant Breed. Crop Sci.
in this study. Maternal effects involved when the
interspecific or drought-adapted parent is used as
maternal parent also need to be further examined.
Finally, the combining ability of black-seeded lines with
interspecific lines should be investigated.
The first author wishes to recognize the support of the
Advisory Service on Agricultural Research for
Development (BEAF) of the Deutsche Gesellschaft für
Technische Zusammenarbeit GmbH (GTZ) for the
accomplishment of this study. The field work was partially
supported by the Tropical Legumes II project managed
by the International Crops Research Institute for the Semi
Arid Tropics (ICRISAT) and is funded by the Bill and
Melinda Gates Foundation.
Abbreviations: Al, Aluminum; CIAT, International Center for
Tropical Agriculture; DF, days to flowering; DII, drought intensity
index; DPM, days to physiological maturity; DW, dry weight;
EGR, economic growth rate; Fe, iron; HI, harvest index; HSD,
honestly significant difference; LAI, leaf area index; MPF, mid-
pod filling; P, phosphorus; PHI, pod harvest index; PPI, pod
partitioning index; SCMR, SPAD chlorophyll meter reading;
SBR, stem biomass reduction; Zn, zinc.
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... From this perspective, it is expected that an improved level of the chlorophyll content possibly rises the photosynthesis rate as well as subsequent seed yields [22]. Several studies report that an increased chlorophyll content delays senescence of leaves under irrigation and mild environmental conditions, and this causes the adequate presence of phosphorus in the leaf tissue by attesting to the findings of the current study [23,24]. The positive correlation between chlorophyll content and photosynthetic rate in dry bean leaves is also specifically reported in the case of compost application and rhizobia inoculation [7,25]. ...
The present study investigates the potential of biomass ash (BA) to produce nutrient-rich vermicompost for recycling within cropping systems. Initially, BA is thoroughly incorporated into dairy manure to obtain the final NPK content of 3.5 (T1), 7.0 (T2), 10.0% (T3) and control specifically is not exposed to BA (T0). The total readily available plant nutrient results indicated that vermicomposting significantly improved bioavailability of the investigated nutrients at the ranges of 0.5–95.6% (T1), 0.5–63.2% (T2), and 0.3–76.5% (T3), depending on the amount of BA in vermicompost. The present study also investigated the effect of BA vermicompost on the growth and yield of dry beans in two different agro-climatic conditions (hot dry summer and temperate regions). The significant increase in plants’ height, pod numbers, dry biomass and grain yield are progressively observed with the increasing dose of BA in vermicompost at both agro-climatic conditions. The mean seed yield is higher in the temperate region (2819 kg ha−1) than in the hot dry summer climatic region (2616 kg ha−1). With this in mind, the increase of 13.80 and 12.99% in biomass and the seed yields are observed in the temperate region, while the biomass and seed yields are increased at 13.04 and 10.28% in the hot dry region due to the BA vermicompost application. The results show that the soil application of nutrient-rich BA vermicompost not only has a beneficial effect on crop production, but also provides viable alternative recycling options to BA in sustainable crop production systems.
... The eight parent MAGIC population had one parental line with high Fe and Zn levels. This line, MIB778, derives its high Fe and Zn from an introgression from P. dumosus and its pedigree is FEB226/G35575-2P//FEB226, where FEB226 is the source of the introgression from P. dumosus (Diaz et al. 2020;Klaedtke et al. 2012). The average linkage disequilibrium (LD) decay in this population was 74 kb. ...
Dry beans, a nutrient-dense dietary staple in Africa, Latin America, and the Caribbean, deliver nutrients such as protein, minerals, and folate, which are often in short supply in other staples. Beans are relatively rich in iron and zinc, two micronutrients for which dietary deficiencies impact billions of people globally. Wide genetic variability in beans seeds, from ~34 to 96 mg/kg for iron and 21 to 59 mg/kg for zinc, led to the recognition that biofortification of beans for maximum levels of these micronutrients is possible through plant breeding. Biofortification efforts to develop bean varieties with seed iron concentrations approaching 90 mg/kg have been underway since the early 2000s. Iron and zinc levels in seeds are positively correlated with each other, and although iron has been the major focus of biofortification efforts, zinc is often evaluated alongside iron. Germplasm diversity screenings have revealed multiple high iron sources in cultivated Andean and Middle American beans as well as wild P. vulgaris and genotypes from closely related species P. dumosus, P. acutifolius, and P. parvifolius. Both seed iron and zinc are moderately heritable traits, and breeding with high iron donor parents based on phenotypic selection has been successfully utilized to achieve genetic gains. To date, at least 60 high iron bean varieties have been released over 12 countries in Eastern and Southern Africa and Latin America. Bean breeders have combined the high iron trait with other traits important to farmers, including seed yield, disease resistance, and abiotic stress tolerance. The application of genomic approaches in breeding high iron beans has been limited. While numerous seed iron and zinc Quantitative Trait Loci (QTL) studies have been undertaken and a meta-analysis identified 12 meta-QTL, 8 of which are for both increased iron and zinc, there has not been much traction in incorporation of these QTL in breeding strategies. Since iron and zinc are quantitative traits controlled by many small-effect QTL, breeders have not found marker-assisted breeding with single or multiple QTL worthwhile. A genomic prediction approach, which in contrast, utilizes thousands of random markers throughout the genome, may be a promising strategy to apply to breeding high iron and zinc beans, and is currently being explored. The prospect of using a transgenic approach to develop high iron and zinc beans is limited at this time due to challenges with plant regeneration and public acceptance of genetically modified (GMO) beans, which may change in the future, and there are many potential candidate genes. The future of biofortification of beans with iron must also look beyond a pure focus on increasing concentration as this approach relies on the assumption that higher iron yields deliver more absorbable iron. To date, one human efficacy study has demonstrated a positive, although slight, effect of biofortification on human iron status. Regardless of concentration, iron from beans can have very low bioavailability due to seed coat polyphenols and phytic acid present in the cotyledons. Evidence from in vitro and animal studies suggests that beans without inhibitory polyphenols and with promoter polyphenols would have higher iron bioavailability and thus deliver more iron. Therefore, redefining biofortification to focus on both iron bioavailability and iron concentration simultaneously in breeding programs has the potential to deliver substantially more nutritional benefits to consumers. The introduction of varieties labeled as high iron beans in Africa and Latin America has largely been met with interest and adoption by farmers and consumers due to strong promotion and the development of varieties with superior yield and disease resistance. Going forward in addition to focusing on iron bioavailability, a greater focus should also be placed on zinc.KeywordsFe fortificationZn fortificationDry beansQTLBiofortified varieties
... Menurut Klaedtke et al. (2012), hasil panen buncis akan terbatas karena rendahnya alokasi bahan kering hasil fotosintesis. Semakin besar fotosintat yang dihasilkan kemudian dialirkan ke dalam polong maka potensi kuantitas dan kualitas hasil akan semakin tinggi. ...
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Balanced organic and inorganic fertilization is expected to improve low nutrient on Inceptisols to increased snap bean production. The effect of the combination of N, P, K, and granule organic fertilizer on bean harvests was the purpose of this study. The parameters were leaf area index (LDA), shoot-root ratio, the weight of pods, pod length, pod diameter, percentage of the number of pods, marketable and unmarketable,and percentage of pods by quality class. The experiment was conducted in February to April 2016 at Ciparanje Experimental Farm, Faculty of Agriculture, Padjadjaran Univeristy, Jatinangor. The study was conducted using a randomized block design (RBD) with 10 treatments and 3 replications. The experimental results showed that N, P, K fertilizer and granule organic fertilizer (GOF) in the order of Inceptisols significantly affected the weight of pods. Application 50% of the dosage N, P, K fertilizer combined with 50% dosage of granule organic fertilizer resulted in a higher pod weight per plot, which reached 2 439.84 g.
... Several studies indicated that superior performance under abiotic stress conditions is associated with more efficient photoassimilate mobilization to pods and enhanced grain formation [5,9,11,12,15,19,41,42]. In this regard, lines such as SMG 12, SMG 21, SMG 22, SMG 27, and SMG 29 showed higher values of PPI (higher pod biomass to canopy biomass ratio) but among these lines, three lines (SMG 12, SMG 21, andSMG 22) showed lower values of PHI, indicating to some extent the "lazy pod syndrome" [9,12,19,23,43]. ...
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Knowledge of the physiological basis for improved genetic adaptation of common bean (Phaseolus vulgaris L.) lines to acid soils and high temperature conditions in the Amazon region of Colombia is limited. In this study, we evaluated the differences among 41 common bean lines in energy use, leaf cooling, photosynthate partitioning to pod formation and grain filling, and grain yield over two seasons under acid soil and high temperature stress in the Amazon region of Colombia. Common bean lines evaluated included medium and large seeded interspecific lines of Mesoamerican and Andean gene pools with different levels of adaptation to abiotic stress conditions and some lines are improved for iron and zinc (biofortified) concentration in seeds. We found three bean lines (GGR 147, SMG 21 and SMG 12) that were superior in their photosynthetic response, leaf cooling, photosynthate partitioning ability to pod formation and grain filling, resulting in grain yields exceeding 1900 kg ha−1 under acid soil and high temperature stress conditions. The superior photosynthetic performance was attributed to the efficient use of absorbed energy on the electron level in thylakoids, which is mainly oriented to a higher quantum yield of PSII (ΦII), lower energy dissipation in the form of heat (ΦNPQ), high linear electron flow (LEF) and high fraction of PSI centers in open state (PSIopen). We speculate that these photosynthetic and photosynthate partitioning responses of superior bean lines are part of the genetic adaptation to acidic soils and high temperature stress conditions. Among the evaluated bean lines, three lines (GGR 147, SMG 21 and SMG 12) combined the desirable attributes for genetic improvement of stress tolerance and biofortification. These lines can serve as parents to further improve traits (energy use efficiency and multiple stress resistance) that are important for bean production in the Amazon region.
... In some cases, the use of weedy types would help reduce the number of backcrosses needed to recover the appropriate seed size (Acosta-Gallegos et al, 2007). Another innovative approach has been the use of lines coming from crosses with the year-bean (for transfer of high iron in the grain) or with tepary (for transfer of bacterial blight resistance) in order to bring more monocarpism into common bean (Klaedtke et al, 2012;Mejía-Jiménez et al, 1994). The bean crop with exceptions in growth habits 1 and 2 still has the ancestral trait of continuing shoot production and lateral flowering, while the first pods already enter into maturity. ...
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This work explains the reasons why a bean collection was established in 1973 at the International Center of Tropical Agriculture (CIAT) near Palmira in Colombia. It shows the impact of the collection on plant breeding and in agricultural development through the distribution of germplasm to the center’s bean breeding program, to successively find resistances to pests and diseases, adaptation to low phosphorus and drought, and more recently higher content of iron and zinc in seeds. The collection was also used to progress knowledge in biological sciences, as shown by a dozen of examples. A reason behind these successes was foresight and focus on diversity per se in the collection. The paper ends with a number of suggestions for the way ahead for the genetic resources conservation and management of these bean crops, and possible take-home lessons for curators in charge of other similar collections.
... According to Polania et al. [29], shoot growth supplies the roots with carbon and certain hormones, in return root growth supplies the shoot with water, nutrients as well as hormones. Increased grain yield through better plant growth in harsh conditions (drought and low fertility) is achieved if the root system is able to supply water and nutrients without absorbing too much photo assimilate from the shoot [30]. Futhermore, associations between roots and fungi, especially mycorrhizal fungi are also an avoidance mechanism of drought [31,32]. ...
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Roots are key organs for water and nutrient acquisition and transport. Therefore, root phenes that are associated with adaptation to low phosphorus (P) environments could enhance top-soil exploration, while deeper allocation is important for acquiring water and mobile nutrients. The understanding of interactions among root phenes can help in the development of common bean (Phaseolus vulgaris L.) genotypes adapted to drought and low fertility through genetic improvement. Two experiments (pot and field) were conducted at the Agricultural Research Institute of Mozambique to assess the contribution of root phenes to common bean shoot biomass and grain yield under combined stress (drought and low P). The pot study assessed eight genotypes, with four treatments combining water regimes (drought and non-stress) and phosphorus levels (200 and 25) mg P kg−1 soil. In the field study, 24 common bean genotypes were also grown in high and low phosphorus (40 kg P ha−1 and without P application) under irrigation and limited water. The grain yield from fields under drought and P stress were correlated with the pot data on root traits. The response of root phenes to drought and phosphorus stress appeared to be related to the deep and shallow root systems, respectively. Deep rooted genotypes produced more total root biomass and high taproot lateral branching density, which resulted in high total root length under drought and low P stress, while shallow rooted genotypes had low total root biomass and less taproot lateral branching. Increased shoot biomass and grain yield under drought and low P was associated with higher mean values of taproot lateral branching density and total taproot length. Genotypes SER 125, BFS 81, FBN12111-66 and MER 22 11-28 showed a greater score of tap root branching density in the pot study with the highest grain yield in the field under low P and drought stress. Therefore, these can be recommended for use in low phosphorus and drought stress environment or serve as parents for improving phosphorus use efficiency and drought tolerance in common bean.
... This suggests that the ability of genotypes to remobilize photosynthate to seed yield could be useful for indirect selection for seed yield under moderate drought conditions (Asfaw et al., 2012;Porch et al., 2009). This approach was used to identify and select superior bean lines with greater assimilate remobilization potential of photosynthate to seed yield under terminal drought (Assefa et al., 2013;Beebe et al., 2008;Klaedtke et al., 2012). Significant positive correlations were also observed among PS traits such as SPAD, Phi2, and PhiNO, with negative correlations between PhiNPQ with SPAD, Phi2, and PhiNO under DS conditions. ...
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Genome‐wide association study (GWAS) was conducted to determine the genetic architecture of yield component and photosynthetic (PS) traits in 256 common bean (Phaseolus vulgaris L.) genotypes from the Andean gene pool. The panel was evaluated under drought stress (DS) and non‐stress (NS) conditions at two locations for two seasons in Uganda and genotyped with 260K single nucleotide polymorphism (SNP) markers. Significant association signals were detected for yield component and PS traits on chromosomes Pv02, Pv03, Pv04, Pv06, Pv09, Pv10, and Pv11. Colocalized GWAS signals were detected for pod weight per plant (PW) and seed yield per plant (SY) on Pv06 with ten significant markers, and for PhiNPQ, LEF, Phi2, and PhiNO on Pv11 under DS. Positional candidate genes were identified within the 1.76 Mb common region for PW and SY under DS on Pv06 including Phvul.006G117500, Phvul.006G119800, and Phvul.006G130500 annotated as Plant invertase/pectin methylesterase inhibitor (INH/PMEI) superfamily protein, involved in sucrose metabolism and signaling. Phvul.006G121200, 14.9Kb upstream of marker S06_23021418 (23.02Mb) on Pv06, encodes Protein phosphatase 2C family protein involved in ABA signaling pathway. Positional candidate genes for PS traits PhiNPQ, LEF, Phi2, and PhiNO on Pv11 under DS were identified including Phvul.011G178200, Phvul.011G178250, Phvul.011G178300, and Phvul.011G178500 between 48.94 ‐ 49.96 Mb annotated as “RING/U‐BOX SUPERFAMILY PROTEIN”, ubiquitin ligase (E3) involved in ABA mediated responses. Significant markers associated with colocalized GWAS signal for SY and PW on Pv06 identified in this study can be validated for marker assisted breeding to improve drought tolerance in large seeded Andean beans. This article is protected by copyright. All rights reserved
... For instance, a recent study demonstrated that although heat stress did not directly affect photosynthesis, it disrupted source-sink relationships through changes in photosynthate transport from source leaves to developing reproductive sink tissues, which resulted in reduced seed set (Soltani et al., 2019). Allocation of photosynthate from reserves in vegetative structures to seeds, measured by traits PHI and PPI, plays a significant role in yield under both drought and low phosphorus stress and also under nonstress conditions (Beebe et al., 2008(Beebe et al., , 2009Klaedtke et al., 2012;Assefa et al., 2013;Rao et al., 2013). PHI varied from 67% to 82%, whereas PPI varied between 33% and 70% . ...
Common bean (Phaseolus vulgaris L.) is arguably the most important grain legume for human consumption, particularly for smallholder farmers across the tropical regions. Common bean provides a critical source of protein to diets, complementing staple sources of carbohydrate. This chapter highlights the agronomic context of production, domestication of modern varieties (including stress-tolerant and biofortified Andean, Mesoamerican, and interspecific genotypes), crop development, the capture and efficiency of radiation, water, and nutrients along with how each of these factors influences yield and nutritional quality. In recent years, major progress has been made to improve grain yield under abiotic stress in the face of climate change. Remobilisation of photosynthate towards grain filling plays a key role in improving resource use efficiency and adaptation to climate change. Continued yield improvements and agronomic support to grow different varieties is required to assist farmers in rapidly adjusting to a changing climate.
... Changes in biomass partitioning under stress determine plants ability to respond to environmental changes that alter resource availability and plants invariably respond by increasing its efficiency of the resource that tends to limit plant growth and finally change its yielding ability. Recently, there has been greater emphasis on remobilization of photosynthates from vegetative parts such as shoot to cob and then from cob on to grains, as an important mechanism of drought resistance (Rao et al., 2012). Aslam et al., (2013) concluded that stem elongation in maize under water stress was reduced during vegetative period. ...
The common bean (Phaseolus vulgaris), a widely consumed legume, originated in Mesoamerica and expanded to South America, resulting in the development of two geographically distinct gene pools. Poor soil condition, including metal toxicity, are often constraints to common‐bean crop production. Several P. vulgaris miRNAs, including miR1511, respond to metal toxicity. The MIR1511 gene sequence from the two P. vulgaris model sequenced genotypes revealed that, as opposed to BAT93 (Mesoamerican), the G19833 (Andean) accession displays a 58‐bp deletion, comprising the mature and star miR1511 sequences. Genotyping‐By‐Sequencing data analysis from 87 non‐admixed Phaseolus genotypes, comprising different Phaseolus species and P. vulgaris populations, revealed that all the P. vulgaris Andean genotypes and part of the Mesoamerican (MW1) genotypes analyzed displayed a truncated MIR1511 gene. The geographic origin of genotypes with a complete vs. truncated MIR1511 showed a distinct distribution. The P. vulgaris ALS3 (Aluminum Sensitive Protein 3) gene, known to be important for aluminum detoxification in several plants, was experimentally validated as the miR1511 target. Roots from BAT93 plants showed decreased miR1511 and increased ALS3 transcript levels at early stages under aluminum toxicity (AlT), while G19833 plants, lacking mature miR1511, showed higher and earlier ALS3 response. Root architecture analyses evidenced higher tolerance of G19833 plants to AlT. However, G19833 plants engineered for miR1511 overexpression showed lower ALS3 transcript level and increased sensitivity to AlT. Absence of miR1511 in Andean genotypes, resulting in a diminished ALS3 transcript degradation, appears to be an evolutionary advantage to high Al levels in soils with increased drought condition.
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Exclusive selection for yield raises, the harvest index of self-pollinated crops with little or no gain in total bipmass. In addition to selection for yield, it is suggested that efficient breeding for higher yield requires simultaneous selection for yield's three major, genetically controlled physiological components. The following are needed: (1) a superior rate of biomass accumulation. (2) a superior rate of actual yield accumulation in order to acquire a high harvest index, and (3) a time to harvest maturity that is neither shorter nor longer than the duration of the growing season. That duration is provided by the environment, which is the fourth major determinant of yield. Simultaneous selection is required because genetically established interconnections among the three major physiological components cause: (a) a correlation between the harvest index and days to maturity that is usually negative; (b) a correlation between the harvest index and total biomass that is often negative, and (c) a correlation between biomass and days to maturity that is usually positive. All three physiological components and the correlations among them can be quantified by yield system analysis (YSA) of yield trials. An additive main effects and multiplicative interaction (AMMI) statistical analysis can separate and quantify the genotype × environment interaction (G × E) effect on yield and on each physiological component that is caused by each genotype and by the different environment of each yield trial. The use of yield trials to select parents which have the highest rates of accumulation of both biomass and yield, in addition to selecting for the G × E that is specifically adapted to the site can accelerate advance toward the highest potential yield at each geographical site. Higher yield for many sites will raise average regional yield. Higher yield for multiple regions and continents will raise average yield on a world-wide basis. Genetic and physiological bases for lack of indirect selection for biomass from exclusive selection for yield are explained.
World pulse production peaked at 58 million MT in 1990 and has since shown a decline in more than 100 countries. Highly fertile land in many countries is being devoted to more profitable cereals, oilseeds, and horticultural crops, thus displacing pulses to less favorable agricultural areas. In less developed countries, the lack of mechanized production, particularly for harvest, has favored a shift to other crops, whereas in developed nations, dry bean (Phaseolus vulgaris L.) production has shifted toward regions of lower-priced land, such as the Canadian prairie (Parker, 1997). For example, Manitoba replaced Ontario as the leading dry bean producer in Canada in 1998. Over the last 25 years, the area planted to dry bean in the U.S.A. has expanded by 30% and while yields have increased by a similar margin, major production shifts have occurred. For example, the acreage planted to dry bean in North Dakota has increased from 13,000 ha in 1971 to 300,000 ha in 1998, whereas the area in Michigan has decreased from 220,000 ha in 1976 to 120,000 ha in 1998. Bean must be regarded by the agricultural sector as a consistently profitable commodity if production is to be maintained in these more traditional areas. Stable prices, consistent consumer demand, and high yield are all essential goals to curtail downward production trends.
The genus was originally defined by Linnaeus (see Delgado Salinas, 1985; Westphal, 1974). The poor initial definition of the genus, together with the biological wealth of tropical forms in this group of legumes, resulted in the naming of hundreds of species (over 400), especially in the period 1810–1910. Early reviews by Bentham (1840), Hassler (1923), and Piper (1926), however, contributed to the clarification of natural groups at a higher level, and lead to the definition of several sections. Consolidation of these sections, mostly after 1950, thanks to the contributions of Urban (1928), Verdcourt (1970), Maréchal et al. (1978), and Lewis & Delgado Salinas (1994), resulted in several new genera, including Vigna, Phaseolus sensu stricto, Macroptilium, Ramirezella, and recently Misanthus. At the International Legume Conference of 1978, a definition of the genus was narrowly defined for a natural group of American legumes within the Phaseolinae with the following main attributes: stipules not extending below insertion, presence of uncinate hairs, floral bracts persistent up to or past flowering, absence of extra floral nectaries, and style not extending beyond the stigma.
This chapter evaluates traits for improving crop yield in water-limited environments. The chapter describes the components of yield and the determinants of survival against which the proposed and demonstrated contributions by traits are critically assessed. Both modern and subsistence agriculture are differentiated mainly by the degree of risk that can be tolerated. Many traits have been proposed for improving the performance of drought-affected crops. Putative traits are more effective in enhancing drought resistance and contributing to grain yield in water-limited environments. The potential value of a trait depends upon the crop and the moisture environment in which it is grown. The chapter presents simulation models, which are very powerful tools for critically assessing the value of putative traits. However, more work is needed in the development and testing of suitable models, and in their application for this purpose. Use of near-isogenic populations as opposed to isogenic lines also appears to hold great promise.
The methods of formal taxonomy have not been very satisfactory for the classification of cultivated plants. As a result, the people who deal with cultivated plants the most have developed their own informal and intuitive classifications based on experience as to what constitutes useful groupings. An attempt is made to provide a framework in which both systems can operate with a minimum of confusion. The structure of the total available gene pool is characterized by assigning taxa to primary, secondary and tertiary gene pools. At the infraspecific level, cultivars are grouped into races and subraces in an informal way without rigid rules for the use of terms.
Increasing water deficit or drought is a problem for dry bean (Phaseolus vulgaris L.) production in the western USA. Identifica- tion of drought-resistant cultivars is crucial for sustainable produc- tion in the region. The objectives of this study were to (i) measure the effects of drought on seed yield, seed weight, and days to maturity; (ii) determine correlation among the three traits in drought-stressed (DS) and nonstressed (NS) environments; and (iii) identify drought- resistant dry bean landraces and cultivars. Three landraces and 17 cul- tivars of race Durango were evaluated in DS and NS environments. Drought intensity index ranged from 0.32 to 0.88. There was a mean reduction in yield of 60% due to drought stress. Also, seed weight was reduced by 14% and maturity was reduced by 4 d in DS. Yield, seed weight, and maturity in NS and DS were positively correlated, and so were seed weight and maturity in NS and DS. But, the DS yield was negatively correlated with seed weight in both DS and NS. The ability to detect yield differences among 20 genotypes decreased with increasing drought stress. Cultivars Viva, NW 63, UI 239, and Com- mon Red Mexican landrace had high yield in both DS and NS and below average reduction in yield due to DS, thus, exhibiting drought resistance. Buster, UI 126, and UI 465 were most susceptible. The fre- quency and timing of irrigation for the four drought-resistant geno- types should be determined and breeding, genetics, and physiology research intensified to maximize yield and water use efficiency in the western USA, which is facing increasing water shortage.
An estimated 60% of common bean (Phaseo- lus vulgaris L.) production worldwide is at risk of drought. A breeding program was devel- oped at the International Center of Tropical Agriculture (CIAT) to create drought resistant breeding lines with varietal potential in the small red, small black, cream (mulatinho) and cream-striped (carioca) grain classes. Breeding populations were created from triple or double crosses. Field screening under terminal drought was performed at Palmira, Colombia in the dry season in F2, F3:5, and F6:8 generations over two cycles of recurrent selection in the small red and small black classes, and one cycle in the mulatinho and carioca classes. Drought resis- tant lines yielded signifi cantly more than com- mercial check cultivars under drought in all color classes. Some outyielded the respective checks by 15 to 25% (depending on color class and trial) in one or more of three favorable envi- ronments, or in the combined analysis across favorable environments, and were also earlier to mature. Drought resistant lines presented up to 36% greater yield d-1 in favorable environ- ments. Some also expressed superior yields in a phosphorus-limited environment. Thus, selec- tion for drought resistance has improved yield potential and plant effi ciency across different environments. It is suggested that selection under drought stress reveals genes that correct ineffi ciencies inherited from the wild Phaseolus vulgaris, and are key to yield improvement of common bean.