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Mardía' is a new almond cultivar released because of its good agronomical traits and very late blooming time, 2 weeks later than 'Felisia', the latest blooming cultivar released so far. It is characterized by its slightly upright growth habit, early ripening, high and regular bloom density, autogamy (S 6 S f genotype), high fruit set, tolerance to diseases, hard shell, large kernel, very high content of oleic acid, and low content of linoleic acid.
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HORTSCIENCE 43(7):2240–2242. 2008.
‘Mardı
´a’ Almond
Rafel Socias i Company
1
, Ossama Kodad, Jose
´M. Alonso,
and Antonio J. Felipe
Unidad de Fruticultura, Centro de Investigacio
´n y Tecnologı
´
a Agroalimentaria
de Arago
´n (CITA), Av. Montan˜ana 930, 50059 Zaragoza, Spain
Additional index words. Prunus amygdalus, breeding, late blooming, self-compatibility, fruit
quality, productivity
Abstract. ‘Mardı
´a’ is a new almond cultivar released because of its good agronomical
traits and very late blooming time, 2 weeks later than ‘Felisia’, the latest blooming
cultivar released so far. It is characterized by its slightly upright growth habit, early
ripening, high and regular bloom density, autogamy (S
6
S
f
genotype), high fruit set,
tolerance to diseases, hard shell, large kernel, very high content of oleic acid, and low
content of linoleic acid.
The almond (Prunus amygdalus Batsch)
breeding program of the Centro de Investi-
gacio´ n y Tecnologı´a Agroalimentaria of
Arago´ n aims to develop new self-compatible
and late-blooming cultivars to solve the main
problem detected in Spanish almond grow-
ing, its low productivity, as a result of the
occurrence of frosts at blooming time or later
and to a deficient pollination (Felipe, 2000).
The first three cultivars released from this
breeding program were Ayle´s, Guara, and
Moncayo (Felipe and Socias i Company,
1987), ‘Guara’ having represented more than
50% of the new almond orchards in the last
years (MAPA, 2002). Later, three more
cultivars were registered in 1998, Blanquerna,
Cambra, and Felisia (Socias i Company and
Felipe, 1999), ‘Blanquerna’ being of very
good productivity and kernel quality, and
‘Felisia’ of very late blooming time (Fig.
1). Two more cultivars, Belona and Soleta,
were registered in 2005 (Socias i Company
and Felipe, 2007) characterized by their high
kernel quality and considered possible com-
mercial substitutes for the two preferred
cultivars in the Spanish market, Marcona
and Desmayo Largueta. The last release from
this breeding program is ‘Mardı´a’, recently
registered because of its good horticultural
and commercial traits.
Origin
‘Mardı´a’ (selection G-2-25, clone 541)
comes from the cross of ‘Felisia’, a self-
compatible and late-blooming release of the
Zaragoza breeding program of small kernel
size (Socias i Company and Felipe, 1999),
and ‘Bertina’, a late-blooming local selection
of large kernel size (Felipe, 2000). This cross
was made with the aim of using two late-
blooming almond cultivars, one of them
carrying the late-bloom allele Lb (Socias i
Company et al., 1999), of very different kernel
size and genetically very distant to avoid the
problems related to inbreeding depression
(Alonso and Socias i Company, 2007).
Blooming Time
Blooming time has been a very important
evaluation trait. As an average, its blooming
time is 25 d later than ‘Nonpareil’, 20 d after
‘Guara’, and 13 d after ‘Felisia’, the latest
blooming cultivar released so far (Fig. 1).
The consistent late blooming time is the
result of very high chilling and heat require-
ments (Alonso and Socias i Company, 2008;
Alonso et al., 2005), much higher than in any
other almond genotype (Table 1). Flowers are
of small size and white with epistigmatic
pistil both on spurs and on 1-year shoots.
Bloom density is regular and high (Kodad
and Socias i Company, 2008b).
Autogamy
Self-compatibility was tested as soon as
the original seedlings produced the first
flowers by examining the arrival or not of
pollen tubes at the ovary after self-pollination
(data not shown). Sets after self-pollination
and autogamy were studied on three grafted
trees of each selection during several years as
a result of the large variability found between
years in field trials for fruit set (Socias i
Company et al., 2005). Average set after
artificial self-pollination was 17.9%, higher
than after crosspollination, 15.7%, showing a
good self-compatible behavior, although this
difference was not statistically significant.
Average set in bagged branches was 9.8%,
higher than the threshold of 6% indicated
by Grasselly et al. (1981) for autogamy, and
23.7% for open pollination. These sets
(Kodad and Socias i Company, 2008a) are
lower than those considered for a commer-
cial crop in Californian cultivars (Kester
and Griggs, 1959), but ensure a good crop
level because of the high bloom density
of this selection, resulting in high produc-
tivity (Kodad and Socias i Company, 2006).
Its S-allele genotype has been determined
as S
6
S
f
(Kodad and Socias i Company,
2008a).
Performance
Field behavior has been evaluated with
three grafted trees in an experimental plot
and in three external trials. One on the most
important points considered was the behavior
in relation to spring frost injury. Especially
important were the observations in 2003 and
2004 with severe frosts in most almond-
growing regions of Spain. Whereas cultivars
considered as resistant to frosts such as Guara
(Felipe, 1988) sustained important yield
reductions, ‘Mardı´a’, as a result of its
extremely late blooming season, did not
sustain any damage (Kodad and Socias i
Company, 2005).
Tree training has been easy because of its
slightly upright growth habit (Kodad and
Socias i Company, 2008b) without the prob-
lem of bending branches of ‘Guara’. Thus,
induction of lateral branching is recommen-
ded during the first years. Adult trees show an
intermediate vigor and branching intensity as
well as a good equilibrium between vegeta-
tive growth and production, thus allowing
reduction of pruning. Field observations in
the different locations showed its tolerance to
Polystigma and other fungal diseases.
Ripening time is early, although later than
in ‘Guara’, which allows the succession of
harvest. Nut fall before harvest has been very
low, but nuts fell easily when shaken. Yield
rating has been slightly lower than for
‘Guara’ (7 versus 8 on a 0 to 9 scale).
The external trials have shown its good
adaptation to different growing and weather
conditions, maintaining a high level of bud
density in all locations (Kodad and Socias i
Company, 2008b). A trial in Anin
˜o´ n (Zaragoza)
at 730 m above sea level and of very cold
climate has had good production even in
years with late frosts. A trial in El Pino´s
(Alacant), at 575 m above sea level but with
a milder climate, has shown their very good
production as well as vegetation (G. Valde´s,
unpublished data). Blooming and ripening
dates observed in these locations have been,
as expected, earlier in El Pino´ s than in
Zaragoza, but later in Anin
˜o´n.
Industrial Quality and Composition
Nut and fruit evaluation has been done
through 7 years according to the IPGRI and
UPOV descriptors. Nuts show a very good
aspect and good size (4.9 ± 0.5 g). The shell is
hard (shelling percentage of 24%), adapted to
Received for publication 31 July 2008. Accepted
for publication 14 Sept. 2008.
The long-term work to develop this cultivar has
been funded by successive research projects, most
recently AGL2007-65853-C02-02 of the Spanish
CICYT, and the activity of the Consolidated Re-
search Group A12 of Arago´n.
We appreciate the technical work of J.M. Anso´n,
M.T. Espiau, J. Bu
´bal, and A. Escota as well as
the collaboration of the industries ‘‘Frutos Secos
Alcan
˜iz’’ and ‘‘Castillo de Loarre,’’ the growers of
the external trials, mainly J.L. Sa´nchez and J.A.
Espiau, and the collaboration of J.L. Espada and
P. Castan
˜er (Centro de Transferencia Agroalimen-
taria de Arago´ n) and G. Valde´ s (Estacio´ Experi-
mental Agra`ria, Elx) in the experimental orchards.
1
To whom reprint requests should be addressed;
e-mail rsocias@aragon.es
2240 HORTSCIENCE VOL. 43(7) DECEMBER 2008
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tsp/horts/175583/03155
the Spanish industry. Kernels also show a
very good aspect and good size (1.2 ± 0.2 g),
heart-shaped, without double kernels (Fig. 2).
Industrial cracking has been carried out by
the Cooperative ‘‘Frutos Secos Alcan
˜iz’’ and
has shown very good results without the
presence of double layers in the shell. Kernel
breakage at cracking has been low with
86.2% of whole kernels.
The chemical composition of the kernels
has been determined to establish their best
use opportunities. The content in protein is
medium and that of oil is high, similar to that
of ‘Marcona’ (Table 2), a very interesting
trait for ‘‘turro´n’’ (nougat) production. The
percentage of oleic acid, that of higher
quality for fat stability and nutritive value
in the lipid fraction, is especially high (Kodad
and Socias i Company, 2008c), close to 75%
(Table 2). The content in linoleic acid, of
lower quality than the oleic acid, is low,
showing a very high ratio of oleic/linoleic
acids (4.5) as another index of high oil
quality. The amount of tocopherol is lower
than in other cultivars (Kodad et al., 2006),
indicating the need for rapid processing of
kernels after cracking.
Roasting has been tested by the industry
‘Almendras Castillo de Loarre’’ for appe-
tizer use. Behavior has been good, although
less than in the favorite one in the Spanish
market, ‘Desmayo Largueta’. Kernel taste,
both raw and roasted, is excellent.
Availability
This cultivar has been presented to patent
on 11 Dec. 2007 at the Spanish Registry
of Protected Cultivars and is available to
Fig. 1. Mean flowering time of ‘Mardı´a’ as related to other cultivars (7-year average). Percentages refer to the amount of flowers opened.
Table 1. Chilling and heat requirements of ‘Mardı´a’
as related to other cultivars.
z
Cultivar
Chilling
requirements
(CU)
y
Heat
requirements
(GDH)
x
Desmayo Largueta 428 5,458
Marcona 428 6,603
Nonpareil 403 7,758
Belona 353 7,741
Soleta 340 7,872
Ferragne`s 444 8,051
Guara 340 8,159
Felisia 329 9,465
Mardı´a 503 10,233
z
Alonso et al., 2005; Alonso and Socias i Company,
2008.
y
Chilling units.
x
Growing degree hours in Celsius.
Fig. 2. Nut and kernel of ‘Mardı´a’.
Table 2. Chemical composition of ‘Mardı´a’ as compared with other cultivars.
Cultivar
Protein
(% DW
z
)
Oil
(% DW
z
)
Oleic
acid
(% oil)
Linoleic
acid
(% oil)
Oleic/linoleic
acid ratio
a-tocopherol
(mgkg
–1
oil)
g-tocopherol
(mgkg
–1
oil)
d-tocopherol
(mgkg
–1
oil)
Total
tocopherol
(mgkg
–1
oil)
D. Largueta 24.5 57.35 70.65 20.55 3.44 304.3 15.3 1.66 321.3
Marcona 23.8 59.10 71.75 19.40 3.70 463.3 18.5 1.87 483.7
Nonpareil 13.0 60.47 67.72 23.28 2.91 400.0 27.8 1.57 429.4
Belona 16.4 65.40 75.60 12.73 5.94 418.4 15.4 2.18 436.0
Soleta 20.0 61.80 69.20 19.70 3.51 214.0 13.3 1.51 228.8
Ferragne`s 25.4 57.53 70.20 20.10 3.49 377.5 18.7 1.84 398.0
Guara 29.3 54.33 63.10 25.70 2.46 385.4 15.7 1.76 402.9
Felisia 27.0 56.32 68.05 22.10 3.08 250.6 18.2 1.73 270.6
Mardı´a 19.8 59.10 74.95 16.55 4.53 201.5 12.1 1.23 214.8
z
Dry weight.
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nurseries though provisional licenses by
Geslive, A.I.E. (C. Juan de Mena 19-3-D,
28014, Madrid, Spain).
Literature Cited
Alonso, J.M., J.M. Anso´n, M.T. Espiau, and R.
Socias i Company. 2005. Determination of
endodormancy break in almond flower buds
by a correlation model using the average
temperature of different day intervals and its
application to the estimation of chill and heat
requirements and blooming date. J. Amer. Soc.
Hort. Sci. 130:308–318.
Alonso, J.M. and R. Socias i Company. 2008. Chill
and heat requirements for blooming of the
CITA almond cultivars. Acta Hort. (in press).
Alonso Segura, J.M. and R. Socias i Company.
2007. Negative inbreeding effects in tree fruit
breeding: Self-compatibility transmission in
almond. Theor. Appl. Genet. 115:151–158.
Felipe, A.J. 1988. Observaciones sobre comporta-
miento frente a heladas tardı´as en almendro.
Rap. EUR 11557:123–130.
Felipe, A.J. 2000. El almendro. I. El material
vegetal. Integrum, Lleida, Spain.
Felipe, A.J. and R. Socias i Company. 1987.
‘Ayle´s’, ‘Guara’, and ‘Moncayo’ almonds.
HortScience 22:961–962.
Grasselly, C., P. Crossa-Raynaud, G. Olivier, and
H. Gall. 1981. Transmission du caracte`re
d’autocompatibilite´ chez l’amandier. Options
Me´diterr. CIHEAM/IAMZ 81:71–75.
Kester, D.E. and W.H. Griggs. 1959. Fruit setting
in the almond: The effect of cross-pollinating
various percentages of flowers. Proc. Amer.
Soc. Hort. Sci. 74:214–219.
Kodad, O. and R. Socias i Company. 2005. Dan
˜os
diferenciales por heladas en flores y frutos y
criterios de seleccio´n para la tolerancia a
heladas en el almendro. Inf. Te´cn. Econ. Agrar.
101:349–365.
Kodad, O. and R. Socias i Company. 2006.
Influence of genotype, year and type of fruit-
ing branches on the productive behaviour of
almond. Scientia Hort. 109:297–302.
Kodad, O. and R. Socias i Company. 2008a. Fruit
set evaluation for self-compatibility selection
in almond. Scientia Hort. 118:260–265.
Kodad, O. and R. Socias i Company. 2008b. Signif-
icance of flower bud density for cultivar evalua-
tion in almond. HortScience 43:1753–1758.
Kodad, O. and R. Socias i Company. 2008c.
Variability of oil content and major fatty acid
composition in almond (Prunus amygdalus
Batsch) and its relationship with kernel quality.
J. Agr. Food Chem. 56:4096–4101.
Kodad, O., R. Socias i Company, M.S. Prats, and
M.C. Lo´pez Ortiz. 2006. Variability in tocoph-
erol concentrations in almond oil and its use
as a selection criterion in almond breeding. J.
Hort. Sci. Biotechnol. 81:501–507.
MAPA. 2002. Spanish Ministry of Agriculture,
Fisheries and Food. 2002. <http//www.mapya.
es/agric/pags/semillas/vivero/almendro.pdf>.
Socias i Company, R. and A.J. Felipe. 1999.
‘Blanquerna’, ‘Cambra’ y ‘Felisia’: Tres nue-
vos cultivares auto´gamos de almendro. Inf.
Te´cn. Econ. Agrar. 95V:111–117.
Socias i Company, R. and A.J. Felipe. 2007. ‘Belona’
and ‘Soleta’ almonds. HortScience 42:704–706.
Socias i Company, R., A.J. Felipe, and J. Go´ mez
Aparisi. 1999. A major gene for flowering time
in almond. Plant Breed. 118:443–448.
Socias i Company, R., J. Go´mez Aparisi, and J.M.
Alonso. 2005. Year and enclosure effects on
fruit set in an autogamous almond. Scientia
Hort. 104:369–377.
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... In this scale, 'Ferragnès' is rated as very late, with the 8 score. Considering the blooming time of some of the new releases (Socias i Company and Socias i Company et al., 2008a, 2015Vargas et al., 2008;Dicenta et al., 2009), later or much later than 'Tardy Nonpareil', this present scale has become inoperable. Consequently, 'Ferragnès' could be considered as a medium-blooming cultivar, and at the GREMPA meeting of Meknès, Morocco, in 1997 it was suggested to reduce this scale and lower 'Tardy Nonpareil' to the rating of 6, leaving the higher ratings of 7, 8 and 9 for later blooming cultivars. ...
... However, this program later introduced 'Titan', a seedling of 'Tardy Nonpareil', where the linkage between late bloom and low productivity had also been apparently broken. Thus, the first late-blooming release, 'Felisia' (Socias i Company and was obtained in the cross 'Titan' × 'Tuono' and the latest releases, 'Mardía' (Socias i Company et al., 2008a) and 'Vialfas (Socias i Company et al., 2015) from "Felisia" × 'Bertina', a late-blooming local selection of unknown origin (Felipe, 2000). These last cultivars are characterised by a permanent late-blooming as determined by very high requirements of both chilling and heating (Table 1). ...
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... Oleic acid and linoleic acid were the most abundant fatty acids, in agreement with previous studies on almonds grown around the world, i.e. in Turkey, Iran, Spain, Italy, China, India, and California (Askin et al., 2007;Kodad et al., 2004Kodad et al., , 2010Kodad and Socias i Company, 2008;Moayedi et al., 2011;Socias i Company et al., 2008;Tian et al., 2011). A negative correlation was observed between oleic acid and linoleic acid concentrations (Pearson r À0.993, P value (two tails) <0.0001) as in other studies (Kodad and Socias i Company, 2008; Kodad et al., 2010Kodad et al., , 2011bSathe et al., 2008). ...
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