Download The Relationship between Corm Weight and Total Flower and Leaf

The Relationship between Corm Weight and Total Flower and Leaf
Number in Saffron
K. Mashayekhi
Horticultural Science Department of Gorgan
University of Agricultural Science and Natural
Resources (GUASNR)
Gorgan
Iran
A. Soltani, B. Kamkar
Agronomy and Plant Breeding
Department of GUASNR,
Gorgan
Iran
Keywords: Crocus sativus , flower number, production
Abstract
Saffron (Crocus sativus) is an opportunity high valuable crop that is
belonged to Iridaceae family. This crop is a perennial, herbaceous and stemless
crop which comprehensive literatures on its agronomic aspects are scarce. In
order to study the effects of corm weight on flower production of saffron two
experiments were conducted during 1989 to 1992 and 1990 to 1992. For this
purpose, A field was sown at 20 Sept. 1989 and flower number was recorded
each day after first flowering day during 4 successive years (EXP1). Another
field was sown in 20 Sept. 1990 and flower number was recorded same, during
three successive years (EXP2). To study the effects of corm weight on saffron
flower production, a wide range of corm weights were sown in 10 lines in each
experiment. In addition to flower number, leaf number of corms during first
three years, also, was recorded. Finally the relationships of corm weight with leaf
number and flower number were studied. Our results indicated that although
total flower number was increased with corm weight increasing in many cases,
but the relationship between corm weight and total flower number was not
considerable (R2EXP1=0.23, R2EXP2=0.2), but the relationship between corm
weight and total leaf number was considerable (R2=0.53). Also, our results
indicated that middle ranges of corm weights are most suitable weight for sowing
and very small or very big corms are not satisfactory.
INTRODUCTION
Saffron (Crocus sativus) is an opportunity high valuable crop (as a spice and
food additive, a medicine and a dye) that is belonged to Iridaceae family. This crop is
a perennial, herbaceous and stemless crop which comprehensive literatures on its
agronomic aspects are scarce. Purple flowers of this crop, which are appeared as the
first organ in autumn are bisexual and have three colored sepals. The flowers include
three stamens with three anthers. The dried stigma is the edible part of this crop. Its
leaves which appear after flowers are narrow and protracted (their length may be
about 30-40 cm).The corms are solid and round. Outer layer of naked corms has 7-8
horizontal circles, which are the nodes of underground stem. Saffron roots are
winnow and short. Depending on corm weight, each corm includes 1-4 apical bud(s)
which are origins of flower and leaves. Between horizontal lines of corms, there are
many small brown spots, which are the origins of cormlets. Saffron propagation
(amplification) is done by these solid cormlets which originated from main corm (so
called mother corm). Corm size varies between 1-20 g/corm. Flowering is done in a
limited period which it takes about 2-3 weeks and the contribution of each corm to
produce flowers, depend on corm size, varies between 1-4 flowers/corm. This may
mean that the corms should have a threshold age to be capable to produce flowers and
increase total flower number. This has demonstrated in sword lily, too. These kinds of
plants can produce flower if their reproductive organs reach to a specific weight and
temperature requirements can be fulfilled. Many researches have conducted to study
the effect of corm weight and size on flower production in many ornamental plants
such as tulip, narcissus and lily. Also the whom which are engaged in flower
production have ranked the corms of these ornamental plants based on their corm size
and weight .In respect of saffron, it has advised to select proper corms that have
adequate ability to flower production. For instance smooth and intermediate corms are
select to sowing in Spain.
Results of an experiment conducted for 5 years on the effect of corm size on its
regeneration capacity and flowering showed that both the production of cormels and
yield of flowers were dependent on the initial size of the corm of planting (Kaushal et
al., 2002).
In trials which were conducted near Bari in 1991-94 using corms produced in
the Civitaretenga and S.Gavino Monreale areas to study the effects of corm size and
planting date on saffron and corm production showed Saffron yields (dry stigmas)
were highest from mother corms >4 cm in diameter. Yields were generally higher
from corms produced in S.GAvino Monreale (Mariz, 1996).
In other study, the yield and quality of saffron (Crocus sativus) plants produced from
corms of various sizes (2.25-2.75, 2.75-3.25 or 3.25-3.75 cm in diameter) were
evaluated in Kargil, Jammu and Kashmir, India. The largest corms (3.25-3.75 cm)
resulted in the highest number of flowers per corm (2.450.45).
MATERIALS AND METHODS
In order to study the effects of corm weight on flower production of saffron
two experiments were conducted during 1989 to 1992 and 1990 to 1992 in Gonbad’s
agricultural campus research filed ((37 25 N, 55  17 E, 37 m). For this purpose, a
field was sown at 20 Sept. 1989 and flower number was recorded each day after first
flowering day during 4 successive years (EXP1). Another field was sown in 20 Sept.
1990 and flower number was recorded same, during three successive years (EXP2).
The fields were under normal situations and all needed treatments were applied to
provide unstressed situations. To study the effects of corm weight on saffron flower
production, a wide range of corm weights were sown in 10 lines in each experiment.
To provide weight ranges the corms were screened precisely and weighted. In
addition to flower Number, leaf Number of corms during first three years, also, was
recorded. Finally the relationships of corm weight with leaf number and flower
number were studied.
RESULTS AND DISCUSSION
The mean flower /year has shown in Figure1 for both experiments. The results
revealed that increasing of corm weight resulted in more flower production to an
upper limit and it has decreased after a ceiling weight in both experiments. Also a
threshold weight for favorable flower production was detected; this advocated that the
corms should have a threshold age (and undoubtedly weight) to be capable to produce
flowers and increasing of total flower number. This has demonstrated in sword-lily
too. The maximum mean flower production per year achieved in corm weight ranges
of (20.15-29.8) and (20.35-25.64) for EXP1 and EXP2, respectively. These results
indicated that the threshold corm weight to ensure acceptable flower production is
around 20 g. On the other hand, mean flower production in mentioned corm weights
was not considerable. This can result in this claim that to reduce sowing costs its
better to select the corms with threshold weight. It should be noted that mean flower
production per year had considerable variations in many cases, even in determined
appropriate corm weights in this research. The regression line between total flower
number and corm weight for both experiments showed that although total flower
number increased with corm weight to an upper limit in many cases, but the
relationship between corm weight and total flower number was not considerable
(R2EXP1= 0.23, R2EXP2=0.2). On the other hand, the values of frequency of withoutflower corms in both experiments (relation to total without- flower corms) in the
corms with higher weight (more than 20 g) were 0 and 1 % in the Exp1 and Exp2,
respectively. These results indicated that small corms are not guaranteed to flowering
during years and if these corms can produce flower in next years (which is likely), the
flowering duration of saffron as a perennial crop will be decreased and it will negate a
valued time of crop to produce more flowers.
Our results on leaf number production in relation to corm weights illustrated
that the relationship between corm weight and total leaf number was considerable
(R2=0.53). These results in companion with obtained results on the effect of corm
size on saffron abilities to produce flower suggested that the intermediate corms can
be considered as the best choice to select corms for sowing as it is true for saffron
cropping systems in Spain too. The results of the study of Kaushal et al., 2002, also
showed that the yield of flowers was dependent on the initial size of the corm of
planting. . In other scarce literatures, the effect of corm size on flowering has
evaluated based on corm diameter. Munsh et al. (2003) indicated that the largest
corms (3.25-3.75 cm) resulted in the highest number of flowers per corm, while Mariz
(1996) also advocated that Saffron yields (dry stigmas) were highest from mother
corms >4 cm in diameter. Any way to link the results of current work with the
reported results by Munsh et al. (2002) and Mariz (1996) the relationship between
corm diameter and corm weight should be investigated.
Literature Cited
Kaushal, S.K. and Upadhyay, R.G. 2002. Studies on variation in corm size and its
effect on cormel production and flowering in Crocus sativus L. under midd hill
conditions of H.P. Research on Crops. 3(1):126-128
Mariz, V. 1996. Resultati di prove culla cultivazione dello zafferano (Crocus sativus
L.)
Atti convegno internazionale:Coltivazione-e-miglioramento di piante
officinali, trento,-Italy, 2-3 giugno 1994. 189-200
Munshi, A. GllZaffar, M. and Zargar, G.H. 2003. Prospects of saffron cultivation in
the cold arid zone of Kargil (Ladakh). Human Impcat on desert environment.434436.
Fig. 1. Mean flower production per year for different corm weights (left: EXP1, right:
EXP2). The numbers on outer circle envelop and the numbers related to radius of
each circle are corm weight and flower numbers, respectively