Floral biology and compatibility in gladiolus
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Date
1999
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Department Of Pomology And Floriculture,College Of Horticulture,Vellanikkara
Abstract
The present investigation on 'Floral biology and compatibility in
gladiolus was conducted in the Department of Pomology and Floriculture,
College of Horticulture, Vellanikkara during the period from July 1997 to
December 1998. The investigations on floral biology, pollen studies and the
extent of compatibility between different varieties were done in the
experimental field of AICRP on Floriculture.
All the varieties showed significant variation among themselves for all
the characters studied. Accession-l showed maximum corm germination
percentage (94.89), plant height (68.86 cm), leaf number (9.44), spike length
(64.67 cm), spike yield per plant (3.11) and took minimum days for spike
emergence (46.56) and first flowering (60.44 days). These desirable qualities
combined in a single variety indicate its scope for using in further breeding
programme. American Beauty had maximum duration of flowering
(12.44 days) and highest cormel number (8.11). Agnirekha had maximum
number of florets per spike (15.00) and corm weight (31.66 g). Mansoer Red
had highest spike weight (25.63 g) and Wedding Bouquet had maximum floret
size (11.14 cm) and cormel size (1.84). Maximum number of florets per spike
was observed in Pacific. It had longest vase life (8.66 days), corm size
(5.18 cm) and conn number (1.78) also. Tambri showed maximum cormel
weight (4.65 g).
In all the varieties fullanthesis occurred from 7.15 a.m. and peak time
was 9.00 a.m. Anthers dehisced within two to three hours after unfurling of
perianth .. Stigma became receptive only after it turned feathery. By 9.30 a.m.
on the day of anthesis stigma turned feathery and after that upto two days it
remained receptive.
White Friendship had maximum pollen fertility (85.90 %) and pollen
production per anther (39500) while Pacific registered highest pollen diameter
(38.09 J.!). Maximum pollen germination was observed in 15 per cent sucrose +
75 ppm boric acid medium for the two varieties studied viz., White Friendship
and Accession-L Pollen viabil ity was the highest when stored in desiccator at
4"C.
High heritability and high genetic advance were observed in characters
I ike days to first flowering, spike length and leaf area: This shows that most
likely the heritability is due to additive gene effects and selection may be
effective for these characters. PCV and GCV were high for leaf area, spike
yield per plant, number of florets open at a time and duration of flowering and
they were low in the case of vase life, spike length, plant height and leaf
number.
The number of florets per spike which determines the market quality
had positive correlation with spike weight, number of florets open at a time and
leaf area. So the number of florets per spike can be increased with the
improvement of any of these characters. A straight away selection from
- gennplasm lines will be very effective for making improvement in this
character. The genotypic correlation coefficients were found to be higher than
the phenotypic correlation coefficients for most of the characters. This
indicates that the environment had lesser effects on these characters.
The direct and indirect effects of 12 characters on number of florets
per spike showed that spike weight had the maximum direct effect on number
of florets per spike: It was followed by duration of flowering, collar girth, spike
length and vase life. The direct selection for the characte-s like spike weight
and duration of flowering would be beneficial for crop improvement, since
these two also showed positive correlation coefficients. Negative direct effects
on number of florets per spike was from days to first flowering, plant height,
floret size, leaf area, leaf number and spike yield per plant. The highest
positive indirect effect on number of florets per spike was of leaf area through
spike weight. The indirect effect of duration of flowering on number of florets
per spike through number of florets open at a time was the lowest. Ten
gladiolus varieties namely, White Friendship, Tambri, Echo Saunder, American
Beauty, Tiger Flame, Wedding Bouquet, Accession-l , Accession-2, Amal and
Pacific were selected and crossed in all possible combinations. In Amal and
Tambri there was no pod development and seed set in both cross pollination
and self pollination tests. In self pollination, pod set, number of seeds per pod
and weight of seeds per pod were higher than that in cross pollination. Pods
took 25 to 35 days to mature. In self compatibility Accession-I had maximum
-pod set (100 %) and highest number of seeds per pod (77.21). Weight of seeds
. per pod was highest in Wedding Bouquet (1.36 g). In cross compatibility, the
pod set was maximum in Accession-2 x White Friendship (91.78 %) and the
number of seeds per pod was highest in Accession-? x Accession-I. Thc
weight of seeds per pod was maximum in Tiger Flame x Amal (0.92 g). The
seed germination percentage was maximum in Pacific (78.94 %) in self
compatibility studies. In cross compatibility the seed germination percentage
was highest in Accession-2 x White Friendship.
The varieties with highest number of florets per spike, vase life and
early flowering were observed in this investigation. Also the compatible
varieties were identified. These varieties can be exploited in further breeding
programmes in gladiolus.
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171459