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Comparative tree growth, phenology and fruit yield of several Japanese plum cultivars in two newly established orchards, organic and conventionally managed

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The growth, phenology and fruit yield of 14 Japanese plum cultivars (Prunus salicina Lindl) were studied in two newly established experimental orchards under organic and conventional management. The experiment was conducted during 2005-2011 in the province of Seville (SW Spain), an important region of Japanese plum culture. Trunk cross-section areas (TCSA), flowering, yield and tree defoliation before winter dormancy were analysed over several years. After one year, TCSA were larger in the organically managed orchard (OMO) for most of the cultivars, in the next two years they were equal, and from the fourth year, several cultivars showed significantly larger TCSA in the conventionally managed orchard (CMO). Flowering in the conventional orchard started from 2 to 6 days before and lasted for 3 to 5 days more than in the OMO. Several cultivars produced significantly more fruit in the CMO, being the average fruit yield in the organic orchard about 72% of the conventionally managed orchard. Autumn defoliation was significantly advanced in the organic orchard, especially in cultivars highly susceptible to rust (Tranzschelia pruni spinosae), a disease not adequately controlled in the organic orchard.
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Introduction
The growth of fruit trees is affected by many di-
fferent factors: plant genetics, soil type, rootstock
(Webster, 1995), climatic conditions (sunlight,
temperature, rainfall, humidity) (Legave et al., 2006)
and there are also agricultural activities having a clear
effect on fitness, vigour, and fruit quality of plants as
the orchard system, irrigation, and fertilization (Hester
& Cacho, 2003; Rufat et al., 2011; Kükükyumuk et al.,
2012).
The different phenological stages of fruit trees, and
their seasonal timing and duration, vary depending on
local climatic conditions and fluctuate from year to year
(Montagnon, 2007). Among the processes that directly
influence the flowering of fruit trees is the accumula-
tion of chill units during the winter (Albuquerque et
al., 2007). Once the minimum number of required chill
units is achieved, appropriate temperatures are needed
to raise the swelling and germination of buds (Melgarejo,
1996). Also, phenology is influenced by variables such
as temperature (Weinberger, 1956; Browning & Miller,
1992; Rodrigo & Herrero, 2002), wind (Dennis, 1979),
frost (Rodrigo, 2000), rain and relative humidity (Gradziel
& Weinbaum, 1999). In addition to the genetic charac-
teristics of different cultivars, there are other factors that
affect the phenology of flowering such as the type of
fertilization (Williams, 1965), the age of the trees or
branches (Robbie & Atkison, 1994) and even the orien-
tation of the branches (Robbie et al., 1993). All these
factors can also affect fruit yield and quality.
In this work, a comparative study of organic and
conventionally managed orchards was conducted exa-
mining differences in tree growth, flowering, fruit yield
and autumn defoliation in two similar experimental
orchards of 14 Japanese plum cultivars.
Comparative tree growth, phenology and fruit yield of several
Japanese plum cultivars in two newly established orchards,
organic and conventionally managed
F. T. Arroyo, J. A. Jiménez-Bocanegra, P. A. García-Galavís, C. Santamaría,
M. Camacho, M. Castejón, L. F. Pérez-Romero and A. Daza*
IFAPA. Centro “Las Torres-Tomejil”. Apdo. Oficial. 41200 Alcalá del Río (Sevilla). Spain
Abstract
The growth, phenology and fruit yield of 14 Japanese plum cultivars (Prunus salicina Lindl) were studied in two
newly established experimental orchards under organic and conventional management. The experiment was conducted
during 2005-2011 in the province of Seville (SW Spain), an important region of Japanese plum culture. Trunk cross-
section areas (TCSA), flowering, yield and tree defoliation before winter dormancy were analysed over several years.
After one year, TCSA were larger in the organically managed orchard (OMO) for most of the cultivars, in the next two
years they were equal, and from the fourth year, several cultivars showed signif icantly larger TCSA in the conventionally
managed orchard (CMO). Flowering in the conventional orchard started from 2 to 6 days before and lasted for 3 to 5
days more than in the OMO. Several cultivars produced significantly more fruit in the CMO, being the average fruit
yield in the organic orchard about 72% of the conventionally managed orchard. Autumn defoliation was significantly
advanced in the organic orchard, especially in cultivars highly susceptible to rust (Tranzschelia pruni spinosae), a
disease not adequately controlled in the organic orchard.
Additional key words: conventional farming; defoliation; flowering; fruit yield; Japanese plum; organic farming;
tree growth.
* Corresponding author: antonio.daza@juntadeandalucia.es
Received: 28-06-12. Accepted: 05-02-13.
Abbreviations used: CMO (conventionally managed orchard); OMO (organically managed orchard); TCSA (trunk cross-section area).
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) Spanish Journal of Agricultural Research 2013 11(1), 155-163
Available online at www.inia.es/sjar ISSN: 1695-971-X
http://dx.doi.org/10.5424/sjar/2013111-3282 eISSN: 2171-9292
Material and methods
Description of the experimental plots
The study was conducted during 2005-2011 in two
similar experimental orchards (5,500 m2each) located
at the IFAPA Centro “Las Torres-Tomejil” in the pro-
vince of Seville in the Guadalquivir River Valley (SW
Spain) (37° 30’ 48’’ N; 5° 57’ 46’’W). The soil was
classified as a Xerofluvent (Soil Survey Staff, 1999).
Both plots were selected on the basis of a similar physico-
chemical soil composition (Table 1) and were 200 m
apart from each other to avoid interference between
the different pesticide treatments. The region has a
Type C Mediterranean climate, according to the Köppen
classification. Relevant agroclimatic conditions regis-
tered in the zone during the time of the study are shown
in Table 2.
In both plots, 14 Japanese plum cultivars (Prunus
salicina Lindl), which matured from late May to mid-
September, were planted in January 2005. Characteris-
tics of the cultivars are described by García-Galavís et
al. (2009). Each experimental plot was subject to a
different type of management, one in organic and the
other in conventional agriculture. In both orchards, the
experiment was set up in a randomised block design
with three replications, each containing 6 trees of each
cultivar.
Major field work conducted in both orchards
Fertilization in the organic plot consisted of the appli-
cation of animal manure (3-4 kg m–2 yr–1) and sowing
of several cover greens containing legumes (Table 3).
A soybean (Glycine max L.) cover green was also sown
in the summer of 2004 before planting the trees. The
conventional plot received annual applications of
mineral manures, including complex formulations (11-
11-11), ammonium nitrate and potassium sulphate, to
155 units of nitrogen, 55 of phosphorus and 150 of
potassium.
The different pest and disease treatments in each
plot were adjusted to regulations in integrated produc-
tion [RD1201/2002 (BOE, 2002); D245/2003 (BOJA,
2003)] and in organic farming [Commiss. Regul. (EC)
834/2007 (OJ, 2007) and 889/2008 (OJ, 2008)]. Speci-
fic products and timing of treatments in both orchards
have been described previously (García-Galavís et al.,
2009). Soil and foliar analyses were conducted as
described by Herencia et al. (2007).
Both plots were irrigated during the dry season by
gravity along two rows parallel to the line of trees with
identical volumes and frequency. Each year, depending
on climatic conditions, from 6 to 9 irrigations were
applied (350,000 L ha–1 each).
Land management consisted of reduced tillage.
When necessary, the grass in the line of trees in the
conventional orchard was removed through the use of
authorized herbicides and in the organic one by a pass
from bleachers with an orchard tractor. The plum trees
had a similar pruning training vessel, taking care that
pruned trees bear a similar width and height in both
orchards.
156 F. T. Arroyo et al. / Span J Agric Res (2013) 11(1), 155-163
Table 1. Physicochemical soil analysis in both orchards at the time of plum tree plantation (2005) and at the end of the
study (2011)
Year Management OM pH EC N P K Ca Mg Fe Mn Zn B
2005 Conventional 1.30 8.6 276 507 5.50 0.72 9.39 1.97 6.64 7.96 0.80 0.96
Organic 1.10 8.6 272 482 9.30 0.68 10.44 1.84 7.28 10.04 0.52 1.06
2011 Conventional 1.60 8.03 435 823 6.03 0.93 58.30 2.46 71.83 99.47 2.83 2.30
Organic 2.90 7.86 401 1,092 5.80 1.16 61.40 3.23 78.43 145.93 3.16 3.06
OM: organic matter. EC: electric conductivity. Units are given in % (OM), mS cm–1 (EC), mg kg–1 (N, P, Fe, Mn, Zn, B) and meq/100 g
(K, Ca, Mg).
Table 2. Agroclimatic conditions registered in the study area
Temperature Relative Rainfall Chilling
Year (°C) humidity (mm) hours
(%)
2007 13.51 69.00 110 617
2008 14.75 63.57 253.80 495.50
2009 12.66 64.01 160.20 749
2010 13.60 79.43 402.40 404
2011 14.43 73.75 195.40 494
Temperature, relative humidity and rainfall are the average for
February-April period (current year). Chilling hours are the
period from November 1st (previous year) until February 15
(current year).
Tree growth and fruit yield
Growth and vigour of the trees were evaluated yearly
in November at the end of the growing season by cal-
culating the cross-section area of the trunk (TCSA)
20 cm above the graft (Layne, 1994; Lepsis & Blanke,
2006).
The fruit yield of each variety (kg tree–1) was calcu-
lated taking into account the total fruit collected in
each orchard, tree replicates with 6 trees each. The cu-
mulative production was obtained by joining the yields
obtained in previous years.
Phenological studies
For phenological studies, data capture was carried
out on nine trees per cultivar (3 per block) and treatment.
According to the BBCH scale (Hack et al., 1992), the
following phenological periods were analysed: opening
of the first flowers, full flowering (> 50% flowers open)
and end of flowering (all petals fallen), and the dura-
tion of flowering was also determined. The kinetics of
falling leaves during senescence was evaluated. The
fall of the leaves was recorded weekly from October
to December. Defoliation was evaluated using a 0-5
scale, where 0 is 0% fallen leaf; 1, 20% fallen leaf; 2,
40% fallen leaf; 3, 60% fallen leaf; 4, 80% fallen leaf
and 5, total defoliation. Evaluation of rust disease
incidence was as described by García-Galavís et al.
(2009).
Statistical analysis
Statistical analyses were performed using Statistix
software (version 9.0, NH Analytical Software, USA).
Analysis of variance (ANOVA) was used to analyze
TCSA and fruit yield data, and defoliation and rust
incidence data were analyzed with the Kruskal-Wallis
nonparametric test at the p< 0.05 level of significance.
Results
Tree growth, soil and foliar analyses
and fruit yield
The TCSA from 2005 to 2011 are shown in Table 4.
In 2005, eight cultivars showed significantly higher
TCSA in the OMO and the other six cultivars showed
non-significant differences between the two manage-
ment systems. In 2006 and 2007, most of the cultivars
displayed similar values in both orchards, except for
Angeleno’ in 2006 (higher in the organic) and ‘Red
Beaut’ in 2007 (higher in the conventional). In 2008,
2009, 2010 and 2011, a total of six, seven, nine and eight
cultivars, respectively, showed significantly higher
TCSA values in the CMO, showing mean increases of
between from 15 to 20%. In these four years, the other
cultivars also showed larger TCSA in the CMO, but
without significant differences. According to the TCSA
values, ‘Souvenir’, ‘Red Beaut’, ‘Angeleno’ and ‘Golden
Japan’were the most vigorous and ‘Friar’and ‘Sapphire’
the least, in both types of management.
Physico-chemical soil composition of both orchards
in 2011 is shown in Table 1. Except for organic matter,
significantly higher in the organic plot, no relevant
differences were observed. Foliar composition of a
strong cultivar (‘Golden Japan’) and other one feeble
(‘Sapphire’) in 2007, 2009 and 2010 is shown in Table 5.
No relevant differences were observed in the major
macro or micronutrients between the two management
systems.
Japanese plum under organic and conventional management 157
Table 3. Gross contribution in dry matter and major macronutrients of the different cover crops
used in the organic orchard
Cover Sowing Buried
kg ha–1
Dry matter N P K
Soybeans (in pre-plant) May 2004 August 2004 10,060 320 34 206
Bean October 2005 March 2006 6,320 180 14 185
Rape + Vetch December 2006 April 2007 2,500 70 8 75
Spontaneous March 2008 2,913 56 9 75
Vetch + Oat October 2008 March 2009 8,320 180 19 220
Bean October 2009 March 2010 10,353 225 24 274
Vetch + Oat October 2010 March 2011 4,100 140 12 120
Fruit production of the different cultivars in the
period 2008-2011 is shown in Table 6. In 2008, ten cul-
tivars had a significantly more fruit production in the
CMO and no variety was higher in the organic treat-
ment. This year, the mean fruit yield was three times
higher in the conventional treatment.
In 2009, only ‘Fortune’, ‘Red Beaut’ and ‘Black
Amber’produced significantly more fruit in the CMO.
The rest of the cultivars did not show signif icant diffe-
rences. No significant differences were obtained in
mean yields of both management types, even though
the organic plot produced around 20% less fruit.
158 F. T. Arroyo et al. / Span J Agric Res (2013) 11(1), 155-163
Table 4. Dynamics of the trunk cross-sectional area (cm2) from 2005 to 2010 of the different cultivars in the organic (O) and
conventionally (C) managed plum orchards
Cultivar
2005 2006 2007 2008 2009 2010 2011
OCOCOCOCOCOCOC
Larry-Ann 10.84 9.60 30.43 41.43 62.99 71.90 72.15 100.04 102.95 137.03* 113.78 155.74* 120.16 193.57*
Fortune 10.75 10.71 41.31 44.01 77.46 80.27 99.98 112.51* 138.44 164.96* 155.37 178.45* 179.73 212.68*
Souvenir 17.31 13.65 61.68 61.81 108.08 109.26 151.92 176.15* 203.39 236.86* 238.75 282.43* 295.11 333.91*
Songold 7.79 7.50 28.02 30.17 58.79 62.60 79.00 92.73* 126.83 136.72 119.96 149.06* 153.68 193.09*
Sapphire 7.64 7.07 31.24 34.68 54.43 68.01 73.53 90.58* 92.44 115.76 102.75 132.75* 118.64 151.55*
Red Beaut 15.36 9.57* 55.29 49.52 104.31 126.84* 148.46 178.40* 205.39 248.32* 245.35 285.34* 293.61 330.19
Laetitia 11.48 8.72* 39.46 40.79 85.49 100.11 117.10 131.51 150.61 198.26* 185.94 220.18 218.72 250.18
Black Amber 11.92 8.62* 35.22 31.96 67.11 70.22 83.21 90.31 124.85 132.34 139.93 151.31 182.88 184.92
Primetime 13.62 9.58* 43.10 43.50 68.26 80.54 100.41 133.10* 141.09 185.55* 166.75 200.06* 200.63 251.80*
Santa Rosa 10.05 7.10* 40.28 35.35 67.56 77.98 95.05 117.27 160.72 174.39 180.73 210.05 232.25 257.84
Angeleno 12.46 8.30* 49.26 41.83* 94.22 94.08 135.39 152.68 185.99 216.41 219.09 271.36* 277.94 329.95*
Golden Japan 13.10 9.58 53.39 48.77 95.72 95.94 131.34 144.97 191.81 207.70 229.90 271.69 281.23 330.58
Friar 6.83 3.42* 22.57 22.70 52.13 48.16 68.72 70.12 74.77 91.53* 100.31 122.88* 116.14 144.29*
Showtime 9.95 6.49 37.26 36.85 56.06 62.71 91.84 87.33 111.13 154.87 137.58 183.52 181.44 235.38
Mean 11.41 8.55* 40.73 40.26 75.72 82.33 103.44 119.84* 143.60 171.48* 166.87 201.06* 203.73 242.85*
Data are the mean of 18 trees for each cultivar and treatment. For each year, the asterisk indicates the existence of significant diffe-
rences of the marked variety between the two types of management (p< 0.05).
Table 5. Foliar composition of ‘Golden Japan’ and ‘Sapphire’ plum cultivars in the two orchards in 2007, 2009 and 2010
Cultivar Management N P K Ca Mg Fe Mn Zn B Cu
2007
Golden Japan Conventional 3.25 0.21 2.34 2.20 0.44 206 112 23 30 1
Organic 2.99 0.22 2.14 2.35 0.45 199 103 25 31 12
Sapphire Conventional 2.58 0.15 2.08 3.03 0.59 334 309 51 < 5 5
Organic 2.78 0.21 1.92 1.31 0.42 289 162 24 13 9
2009
Golden Japan Conventional 3.63 0.26 2.09 1.26 0.41 322 75 25 33 12
Organic 3.14 0.23 1.73 0.97 0.43 217 72 22 30 10
Sapphire Conventional 2.47 0.22 2.63 1.62 0.42 279 58 21 33 12
Organic 2.95 0.23 2.05 1.30 0.42 193 77 24 30 11
2010
Golden Japan Conventional 2.76 0.21 1.97 0.88 0.33 194 76 18 32 9
Organic 2.65 0.24 1.72 0.83 0.33 192 90 19 36 10
Sapphire Conventional 1.95 0.21 2.27 1.14 0.36 190 96 18 31 10
Organic 2.56 0.20 1.85 1.10 0.34 181 100 20 33 10
Units are given in % (N, P, K, Ca, Mg) and mg kg–1 (Fe, Mn, Zn, B, Cu).
In 2010, five cultivars had significant higher fruit
yields in the CMO. Fruit production of ‘Sapphire’,
‘Showtime’and ‘Black Amber’was higher in the orga-
nic orchard, although only the last cultivar showed a
significant difference. Again this year the mean fruit
yield did not show a significant difference.
In 2011, ‘Souvenir’, ‘Laetitia’ and ‘Black Amber’
produced significantly more fruit yield in the conven-
tional orchard, while ‘Songold’ and ‘Showtime’ pro-
duced significantly more in the organic system. Signi-
ficant differences were not observed in the average
yield.
Except for 2008, with a production still erratic,
the average fruit production of the organic orchard
ranged between 71% and 82% of the conventional one.
The 2008-2011 cumulative production showed se-
ven cultivars with a significant higher yield in the
CMO.
Flowering
The accumulation of chill units during the cold season
(from November 1 to February 15), and the tempera-
tures, relative humidities and rainfall in the flowering
periods (the average of the months of February, March
and April) are shown in Table 2.
The 2007-2010 periods of flowering of the different
cultivars are shown in Fig. 1. In 2007, ‘Sapphire’,
‘Friar’, ‘Black Amber’, ‘Songold’, and ‘Santa Rosa’
showed a significantly earlier flowering in the CMO.
A non-significant earlier flowering in the OMO was
observed in ‘Laetitia’ and ‘Larry-Ann’. The cultivars
‘Red Beaut’, ‘Fortune’, ‘Souvenir’, ‘Showtime’ and
Angeleno’ began to flower at the same time in both
treatments. ‘Songold’, ‘Red Beaut’, ‘Santa Rosa’,
Angeleno’ and ‘Sapphire’ showed a flowering period
significantly longer in the CMO, whereas only ‘Friar’
had a significantly longer flowering in the organic
orchard.
In 2008, ‘Larry Ann’, ‘Fortune’, ‘Red Beaut’, ‘Black
Amber’ and ‘Angeleno’ initiated flowering simulta-
neously in both orchards, whereas the other cultivars
showed an earlier flowering in the CMO, specially ‘Friar’,
‘Laetitia’ and ‘Showtime’ (Fig. 1).
In 2009, only ‘Fortune’ initiated flowering simulta-
neously in both orchards and the remaining 13 cultivars
showed a significant earlier flowering in the CMO,
exception made for ‘Primetime’.
In 2010, 12 cultivars displayed an earlier onset of
flowering in the conventional plot, showing significant
differences in nine of them, ‘Fortune’, ‘Songold’,
‘Laetitia’, ‘Golden Japan’, ‘Black Amber’, ‘Primetime’,
‘Santa Rosa’, ‘Angeleno’ and ‘Showtime’.
Japanese plum under organic and conventional management 159
Table 6. Comparative fruit production (kg tree–1) of several Japanese plum cultivars from organic (O) or conventionally (C)
managed orchards from 2008 to 2011
Cultivar
2008 2009 2010 2011 Accumulated
OCOCOCOC O CO/C
Larry-Ann 1.16 14.50* 16.33 17.16*12.66*24.66* 22.88 9.44*33.54 64.77* 0.52
Fortune 0.66 5.16* 13.16 18.83* 12.33*17.33*25.55 28.00 *51.55 69.00*0.74
Souvenir 1.66 5.00* 16.83 26.50*9.33*16.33*12.66 33.88* 40.32 81.54* 0.49
Songold 5.16 14.00* 19.83 18.66*35.83*72.16* 15.00 6.16* 75.67 110.49* 0.68
Sapphire 4.16 7.33*23.00 35.66*14.66*10.66*13.55 19.11*55.21 74.44*0.74
Red Beaut 0.83 9.00* 5.50 14.50* 9.00*9.50*9.33 16.33*24.66 49.33* 0.49
Laetitia 2.33 6.16*42.00 24.16*14.50*15.00*26.11 35.55* 84.44 80.88*1.04
Black Amber 6.00 8.50*8.33 23.00* 38.66* 22.16*3.88 49.09* 56.54 102.75* 0.55
Primetime 1.33 15.00* 12.83 27.33*20.50*52.33* 5.72 2.88 *40.05 97.21* 0.41
Santa Rosa 0.50 2.33* 9.33 16.16*7.16*6.50*10.11 6.72*26.77 31.38*0.85
Angeleno ND ND ND ND 5.33*23.33* ND ND ND ND ND
Golden Japan 14.00 27.50* 63.16 51.66*56.00*66.33* 62.22 55.00*195.38 200.49*0.97
Friar 0.50 12.33* 36.16 48.50*2.50*2.50*37.77 55.27*76.77 118.27* 0.65
Showtime 3.83 7.33* 21.66 25.00*35.00*30.16*28.05 11.44* 88.55 73.94*1.19
Mean 3.24 10.29* 21.34 27.52*19.19*26.70*20.98 25.29*64.75 89.80*0.72
Ratio O/C 0.31 0.77 0.71 0.82 0.72*
Data are the mean of 18 trees for each cultivar and treatment. ND: not determined. For each year the asterisk indicates the exis-
tence of significant differences between both types of management (p< 0.05).
Average data of the flowering period in all the four
years revealed that flowering in the conventional
orchard started from 2 to 6 days before and lasted for
3 to 5 days more than in the OMO (Table 7).
Leaf fall
Defoliation was evaluated several years from Octo-
ber to December. Fig. 2 shows a detailed defoliation rate
for all of the cultivars in both orchards in 2008. At the f irst
sampling in third week of October, 10 cultivars showed
significantly less foliage in the OMO. In two subse-
quent samplings, performed in the first and fourth
week of November, all the cultivars showed a signifi-
cantly higher leaf drop in the OMO. In the second week
of December, all of the cultivars were completely
defoliated in the organic orchard. In the conventional plot,
‘Red Beaut’, ‘Black Amber’, ‘Friar’and ‘Showtime’were
also completely defoliated at this time and for the
other cultivars 100% of defoliation was achieved by
the fourth week of December. An average premature
defoliation was detected in the OMO all the years
(Fig. 3).
‘Showtime’, ‘Friar’, ‘Larry-Ann’, ‘Santa Rosa’and
‘Sapphire’ showed the higher degree of premature
defoliation in the organic plot, while ‘Souvenir’ and
‘Golden Japan’had minor differences in both orchards,
and the other cultivars showed an intermediate beha-
viour. Susceptibility of different Japanese plum culti-
vars to rust disease caused by Tranzschelia pruni spino-
sae was evaluated, and as shown in Fig. 4, the most
defoliated cultivars were those which showed the
greatest sensitivity to rust infection.
160 F. T. Arroyo et al. / Span J Agric Res (2013) 11(1), 155-163
40 50 60 70 80 90 100 110 40 50 60 70 80 90 100 40 50 60 70 80 90 100 40 50 60 70 80 90 100
Days of year 2007 Days of year 2008 Days of year 2009 Days of year 2010
Larry Ann
Fortune
Souvenir
Songold
Sapphire
Red Beaut
Laetitia
Black Amber
Primetine
Santa Rosa
Angeleno
Golden Japan
Friar
Showtime
Conventional Organic Full bloom
Figure 1. Flowering period of the different Japanese plum cultivars in both orchards in 2007-2010.
Table 7. Characteristics of 2007-2010 flowering periods in organic and conventionally mana-
ged plum orchards
Period of flowering
Year Treatment
Beginning Full End Duration
(days)
2007 Organic March 6 March 17 April 3 28
Conventional March 4 March 19 April 4 31
2008 Organic February 26 March 6 March 28 30
Conventional February 22 March 2 March 28 34
2009 Organic February 22 March 4 March 16 22
Conventional February 18 March 1 March 17 27
2010 Organic March 1 March 16 April 2 33
Conventional February 24 March 13 April 2 38
Data are the average of the 14 cultivars.
Discussion
Organic farming has been regulated in Europe for
almost two decades. Among the strengths of this sys-
tem is a great respect for the environment, food quality
and safety (Pfiffner & Niggli, 1996; Hole et al., 2005;
Gabriel & Tscharntke, 2007), whereas the weaknesses
are often lower yields and the difficulty of controlling
pests and diseases (Leake, 1999; Weibel et al., 2007;
De Ponti et al., 2011). Organic tree plantations can be
completed through a conversion period of three years
from a conventional pre-established planting or starting
the organic management from ‘scratch’. In this study,
we evaluated the effect of two types of management,
conventional and organic, on tree growth, yield and
some phenological events of different Japanese plum
cultivars in two newly established orchards.
After the first year of growth in 2005, we observed
that several cultivars had larger TCSA in the organic
orchard. During 2005, fertilizers were not added to
both orchards, but during the summer of 2004 a highly
nutritious soybean plant cover was planted and incor-
porated into the OMO, which could explain these diffe-
rences. In the next two years, 2006 and 2007, no diffe-
rences were found between treatments, but from the
fourth year, when fruit production began, various cul-
tivars had larger TCSA in the conventional orchard,
and differences still persisted seven years after planting.
It seems that likely the difference of vigour may be
because of the type of fertilizer applied, though a simi-
lar foliar content was observed, and even they were
within the optimum ranges (Sanz et al., 1991).
The lower tree vigour observed in the OMO might
be the cause of the delay in the initiation of bud breaking
and flowering and the shorter flowering period. The
difference of vigour also led to different yields in both
orchards for most of the cultivars.
Another relevant difference observed between both
orchards was that defoliation occurred approximately
one month earlier in the OMO, and this symptom was
especially evident for cultivars suffering high levels of
rust disease. García-Galavís et al. (2009) evaluated the
susceptibility of the cultivars used in this assay to diffe-
rent pests and diseases and they found that rust fungal
disease affected more intensively the OMO. Therefore,
in organic plum orchards, in addition to optimizing the
application of organic fertilizers, it is important to
Japanese plum under organic and conventional management 161
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4
5
Defoliation degree
293 310 324 338 352 293 310 324 338 352
Day of year
Red Beaut Friar
Laetitia Showtime
Songold Angeleno
Shappire Golden Japan
Fortune Primetime
Souvenir Santa Rosa
Larry-Ann Blackamber
Figure 2. Defoliation rate based on a 0-5 scale of different Ja-
panese plum cultivars in both orchards from October 15 to De-
cember 31, 2008. Black line, organically managed orchard; grey
line, conventionally managed orchard.
0.00
1.00
2.00
3.00
4.00
5.00
2009 2010 2011
Defoliation degree
Organic Conventional
Figure 3. Defoliation degree in each orchard in 2009, 2010 and
2011. Data correspond to the third week of October each year
and are media of the 14 cultivars used in the study.
achieve adequate control mechanisms against rust di-
sease or to use the least susceptible cultivars to this
fungus. However, other physiological factors could be
involved, because cultivars with low susceptibility to
rust disease, such as ‘Red Beaut’ and ‘Souvenir’, also
showed an earlier leaf drop in the OMO (Fig. 2).
As local weather conditions during the years of the
study can be considered normal, it is conceivable that
they may have not caused an atypical distortion in the
observed results. Only specific aspects deserve to be
highlighted; for example in 2010 the cultivar ‘Friar’only
sparsely flowered due to the low number of chilling
hours, and this occurred equally in both orchards. Mo-
reover, technical difficulties prevented to determine ade-
quately the yield of the late variety ‘Angeleno’. Fruit qua-
lity parameters were reported recently (Daza et al., 2012).
We think that this study highlights on some physio-
logical and phenological aspects of the stone fruit trees
managed in organic agriculture and could explain the
lower yield usually observed in the organic systems
(De Ponti et al., 2012).
Thus, it seems clear that even on fertile soil, as was
in this study, the OMO leads to plum trees with lower
vigour than the CMO. Given that leaf and soil composi-
tions did not show nutrient differences that would ade-
quately explain the differences likely the premature
defoliation observed in the organic treatment causes a
decreases in the accumulation of nitrogen and carbohy-
drate reserves in the roots and branches before the winter
dormancy phase, which might also influence the vigour
of trees and also the productivity. We are currently wor-
king on this hypothesis, but this is complex to analyze
in mature trees, and our results are still preliminary.
In this work was not conducted a comprehensive
study of the economic cost in both types of manage-
ment, but we can indicate some general aspects. The
cost of the products used to combat pests and diseases
was about 20% higher in the organic orchard. Irrigation
and tillage were similar, and fertilization was some-
what more costly in the organic system, but pruning
was more economical. In conclusion, we believe that
organic plum production was somewhat more expen-
sive mainly due to its lower yield.
Acknowledgments
The authors acknowledge the technical collabora-
tion provided by V. Méndez, M. Andra and R. Cabezas.
Funding was provided by INIA-FEDER (Projects
RTA2006-00054-00-00 and RTA 2010-00046-00-00).
References
Alburquerque N, Carrillo A, García-Montiel F, 2007. Esti-
mación de las necesidades de frío para florecer en varie-
dades de cerezo. Frut Prof 164: 5-12.
BOE, 2002. Real Decreto 1201/2002 of November 20.
Boletín Oficial del Estado 287, 30/11/2002.
BOJA, 2003. Decreto 245/2003 of Junta de Andalucía,
September 2. Boletín Oficial de la Junta de Andalucía
174, 10/09/2003.
162 F. T. Arroyo et al. / Span J Agric Res (2013) 11(1), 155-163
01 23 45012345
Showtime
Friar
Golden Japan
Angeleno
Santa Rosa
Primetime
Blackamber
Laetitia
Red Beaut
Sapphire
Songold
Souvenir
Fortune
Larry-Ann
Defoliation degree Rust incidence
116.5 a
113.0 a
16.0 a
67.5 abcde
83.0 abc
60.0 abcde
67.5 abcde
36.5 cde
60.0 abcde
75.5 abcd
21.5 de
10.50 e
52.0 bcde
109.5 ab
110.0 a
110.0 a
63.0 abc
27.5 bc
102.5 a
41.0 bc
41.0 bc
81.0 ab
27.5 bc
61.0 abc
68.0 abc
19.0 c
27.5 bc
110.0 a
LSD = 59.48
LSD = 59.48
Figure 4. Defoliation degree (left) and rust incidence (right) on different Japanese plum cultivars in an organically managed
orchard in the third week of October, 2007. The length of the bars represents the defoliation degree or the disease level on the
0-5 scale. Numbers indicate the mean values in the Kruskal-Wallis test. Different letters indicate that the means are significantly
different at p< 0.05. LSD, least significant difference.
Browning G, Miller JM, 1992. The association of year-to
year variation in average yield of pear cv. Conference in
England with weather variables. J Hort Sci 67: 593-599.
Daza A, Camacho M, Galindo I, Arroyo FT, Casanova L,
Santamaría C, 2012. Comparative fruit quality parameters
of several Japanese plum varieties in two newly established
orchards, organic and conventionally managed. Int J Food
Sci Technol 47: 341-349.
De Ponti T, Rijk B, Van Ittersum MK, 2012. The crop yield
gap between organic and conventional agriculture. Agric
Syst 108: 1-9.
Dennis FG, 1979. Factors affecting yield in apple with
emphasis on “Delicious”. Hort Rev 1: 395-422.
Gabriel D, Tscharntke T, 2007. Insect pollinated plants
benefit from organic agriculture. Agric Ecosyst Environ
118: 43-48.
García-Galavís PA, Santamaría C, Jiménez-Bocanegra JA,
Casanova L, Daza A, 2009. Susceptibility of several Japa-
nese plum varieties to pests and diseases in a newly esta-
blished organic orchard. Sci Hort 123: 210-216.
Gradziel TM, Weinbaum SA, 1999. High relative humidity
reduces anther dehiscence in apricot, peach and almond.
Hortscience 34: 322-325.
Hack H, Bleiholder H, Buhr L, Meier U, Schnock-Fricke U,
Weber E, Witzenberger A, 1992. Einheitliche Codierung
der phänologischen Entwicklungsstadien mono-und diko-
tyler Pflanzen-Erweiterte BBCH-Skala, Allgemein. Nach-
richtenbl Deut Pflanzenschutz 44: 265-270.
Herencia JF, Ruiz-Porras JC, Melero S, García-Galavís PA,
Morillo E, Maqueda C, 2007. Comparison between or-
ganic and mineral fertilization for soil fertility levels,
crop macronutrient concentrations, and yield. Agron J 99:
973-983.
Hester SM, Cacho O, 2003. Modelling apple orchard systems.
Agric Syst 77: 137-154.
Hole DG, Perkins AJ, Wilson JD, Alexander IH, Gice PV,
Evans AD, 2005. Does organic farming benefit biodiver-
sity? Biol Conserv 122: 113-130.
Kükükyumuk C, Kaçal E, Ertek A, Óztürk G, Kukul Kurttafl
YS, 2012. Pomological and vegetative changes during
transition from flood irrigation to drip irrigation: Star-
krimson Delicious apple variety. Sci Hort 136: 17-23.
Layne REC, 1994. Prunus rootstocks affect long-term orchard
performance of ‘Redhaven’ peach on Brookston clay
loam. HortScience 29: 167-171.
Leake AR, 1999. A report of the results of CWS agriculture’s
organic farming experiments. J R Agric Soc Engl 160:
73-81.
Legave JM, Segura V, Fournier D, Costes E, 2006. The effect
of genotype, location, and their interaction on early growth
in apricot trees. J Hortic Sci Biotechnol 81: 189-198.
Lepsis J, Blanke MM, 2006. The trunk cross-section area as
a basis for fruit yield modelling in intensive apple orchards.
Acta Hort (ISHS) 707: 231-235.
Melgarejo P, 1996. El frío invernal, factor limitante para el
cultivo frutal. Modelos y métodos para determinar la acu-
mulación de frío y de calor en frutales. Ed A Madrid Vi-
cente. Madrid. 166 pp.
Montagnon JM, 2007. Las ciruelas japonesas. Elección de
las variedades polinizadoras. Frut Prof 164: 25-32.
OJ, 2007. Directive 834/2007/EC of the Council of June 28.
Official Journal of the European Union L 189 20/07/2007.
OJ, 2008. Directive 889/2008/EC of the Council of Septem-
ber 5. Official Journal of the European Union L 250
18/09/2008.
Pfiffner L, Niggli U, 1996. Effects of biodynamic, organic
and conventional production systems on ground beetles
(Col. Carabidae) and other epigaeic arthropods in winter
weat. Biol Agric Hort 12: 353-364.
Robbie F A, Atkison CJ, 1994. Wood and tree age as factors
influencing the ability of apple flowers to set fruit. J Hort
Sci 69: 609-623.
Robbie FA, Atkison CJ, Knight JN, Moore KG, 1993. Branch
orientation as a factor determining fruit set in apple trees.
J Hort Sci 68: 317-335.
Rodrigo J, 2000. Review: spring frost in deciduous fruit
trees-morphological damage and flower hardiness. Sci
Hort 83: 155-173.
Rodrigo J, Herrero M, 2002. Effects of pre-blossom tempera-
tures on flower development and fruit set in apricot. Sci
Hort 31: 125-135.
Rufat J, Domingo X, Arbones A, Pascual M, Villar JM, 2011.
Interaction between water and nitrogen management in
peaches for processing. Irrig Sci 29: 321-329.
Sanz M, Heras L, Montañes L, 1991. Foliar diagnosis in
peach tree: reference nutrient contents throughout the
season. An Est Exp Aula Dei 20: 67-73.
Soil Survey Staff, 1999. Soil taxonomy, 2nd ed. USDA Ag.
HBK. 437, Washington, USA.
Webster AD, 1995. Rootstock and interstock effects on
deciduous fruit tree vigour, precocity and yield producti-
vity. New Zeal J Crop Hort Sci 23: 373-382.
Weibel FP, Tamm L, Wyss E, Daniel C, Häseli A, Suter F,
2007. Organic fruit production in Europe: successes in
production and marketing in the last decade, perspectives
and challenges for the future development. Acta Hort 737:
163-172.
Weinberger JH, 1956. Prolonged dormancy trouble in peaches
in the southeast in relation to winter temperatures. Proc
Am Soc Hort Sci 67: 107-112.
Williams RR, 1965. The effect of summer nitrogen applica-
tions on the quality of apple blossom. J Hort Sci 40: 31-41.
Japanese plum under organic and conventional management 163
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The purpose of this study was to identify relevant variables and appropriate stages in tree development to determine, as early as possible, genetic differences in growth and branching of apricot trees. Quantitative growth and branching traits of young trees were studied in four genotypes planted at three locations in the French growing area. Over the first three years of growth, the organisation of ten limbs was described for each genotype X location combination using 'AMAPmod' methodology. From the first year, the length, diameters, volume and sylleptic branching of limbs were influenced by genotype. In the second and third years, genetic variability was more clearly detected when cumulative variables, rather than annual variables, were considered on the cumulative components of limbs. At all three locations, the diameters, volume and number of long laterals were greatly affected, in particular, by genotype when the data were accumulated over the first 2 years. In addition, the abortion of short laterals developed on the first annual shoot was influenced by genotype. In contrast, from the second year, location clearly affected the length and number of "growth units" of limbs. As regards branching, location influenced the number of sylleptic shoots in the first year, then the number of long lateral shoots in the second year. Finally, the study showed that genetic differences in growth and branching need at least 3 years to be expressed on appropriate parts of the limbs and could be used to assess early breeding criteria for tree vigour and form.
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Performance of `Redhaven' peach [Prunus persica (L.) Batsch.] propagated on nine experimental Prunus rootstock was evaluated over 8 years beginning in 1984, in a randomized complete-block experiment with 10 replications on a Brookston clay loam soil type near Harrow, Ont. This experiment was part of an interregional NC-140 peach rootstock experiment. Significant rootstock-induced effects were noted for increase in trunk cross-sectional area, cumulative tree height and spread, cumulative number of root suckers, yield, average fruit weight, yield efficiency, winter injury, cold hardiness, and tree survival. None of the clonally propagated rootstock gave satisfactory overall performance. All trees on GF655-2, 80% on GF677, 60% Self-rooted, and 50% on GF1869 were dead by the eighth year. In addition, suckering was a major problem on GF1869 and a moderate problem on GF655-2. `Citation' induced the most scion dwarfing but had the lowest yields and low yield efficiency. When yield, yield efficiency, fruit size, and tree mortality were considered together, the four peach seedling rootstock performed better than the other Prunus rootstocks and were ranked as follows: Siberian C, Halford, Bailey, and Lovell. Of these, the first three could be recommended with the most confidence to commercial growers who grow peaches on fine-textured soils in northern regions.
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The regulation of anther dehiscence by relative humidity (RH) was assessed for detached anthers and detached whole flowers from a limited selection of apricot (Prunus armeniaca L.), peach [P. persica (L.) Batsch], and almond [P. dulcis (Mill.) D.A. Webb, syn. P. amygdalus Batsch; P. communis (L.) Arcangeli, non Huds.] genotypes, as well as an almond X peach F2 progeny. Dehiscence was evaluated at 33, 64, 87, 93 and 97% RH for detached anthers, and at 33, 64 and 97% RH for whole detached flowers. Anther dehiscence was suppressed with increasing RH for all genotypes. Apricot anthers showed the greatest dehiscence at low RH and measurable dehiscence at high RH even when detached. Anther dehiscence in almond appeared more suppressed than in apricot at all RH levels tested, being completely suppressed by high RH in detached anthers. Peach genotypes exhibited the full range of variability between apricot and almond patterns. Evidence for transgressive segregation of RH-controlled anther dehiscence was observed in the occurrence of cleistogamy in an almond x peach F2 progeny. Rates of anther dehiscence were approximately linear with change in RH in detached anthers but exhibited a more buffered, step-wise response when detached whole flowers were tested. Results are consistent with field observations, and highlight the low but measurable risk of cleistogamy in these species, as well as opportunities to modify the breeding systems and crossing environments to facilitate controlled hybridization, and to reduce pollination vulnerability to adverse environments.