INHERITANCE OF GYNOECY, PARTHENOCARPY AND YIELD RELATED TRAITS IN INDIAN CUCUMBER
Loading...
Date
2016
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
DIVISION OF VEGETABLE SCIENCE ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE, NEW DELHI –
Abstract
The present investigation was undertaken during 2012-2014 with the
objectives (i) to study the heterosis, combining ability and gene action for earliness
and yield traits (ii) to study the inheritance of gynoecy and parthenocarpy (iii)
generation mean analysis for earliness and yield traits (iv) molecular mapping of
gynoecious (F) locus in cucumber. The seven diverse inbred lines of cucumber were
crossed in a half diallel fashion without reciprocals to generate 21 F1 hybrids. These
seven parental lines and their 21 F1 hybrids were evaluated for estimation of
heterosis, combining ability and gene action. The observation were recorded for ten
quantitative characters viz. node number of first female flower, days to first female
flower anthesis, days to fruit set from opening of first female flower, days to first
fruit harvest, number of fruits per plant, fruit length, fruit diameter, average fruit
weight, vine length and yield per plant.
Based on the performance of 21 F1 hybrids three best performing hybrids
PPC-2 × Pusa Uday, GPC-1 × Punjab Naveen and PPC-2 × Punjab Naveen showed
64.51%, 55.61%, and 54.57% heterosis respectively, over standard check Pusa Uday
for yield per plant. Hence, these hybrid can be exploited commercially for earliness
and yield per plant and may be tested under multi-locational trials. The most
outstanding parental lines involved in all F1 crosses which showed best GCA effects
are GPC-1, PPC-2 and Pusa Uday. The F1 hybrid showed promising results when
atleast one of the parental lines exhibiting high GCA effect for yield and its
component traits were involved in the crosses. Highest SCA effect for total yield per
plant was shown by hybrid GPC-1 × PPC-2, PPC-2 × Pusa Uday and GPC-1 ×
Punjab Naveen. These combinations may be exploited for commercial hybrid
production. From the above cross combination it is clear that gynoecious as one of
parent in cucumber hybrid development holds immense potentiality for exploitation
of hybrid vigour with respect to earliness, yield and other yield related traits.
The analysis on genetic components of variance revealed over dominance
gene action and narrow sense heritability was found to be < 50 per cent for most of
the characters except for average fruit weight, where, partial dominace is more
predominant. The over dominance and low narrow sense heritability for most of the
102
characters studied suggested the significance of heterosis breeding to get higher gain
in cucumber.
The results of generation mean analysis showed the significance of additive,
dominance and epistatic interaction in most of the crosses for ten important
quantitative characters. Simple mass selection would be effective for improvement
of the characters governed by additive gene effects, heterosis breeding for characters
governed by dominance gene effects and breeding plan based on restricted selection
by way of intermating the most desirable segregants followed by selection and/or
diallel selective mating system would be most appropriate for characters where
duplicate epistasis was predominant. Complementary epistasis was observed for
yield per plant, which would increase the heterosis in positive direction.
The segregation of F2 population into 3 (gynoecious): 1 (monoecious) plant
suggested that single dominant gene controled the gynoecious sex in cucumber
particularly in gynoecious genotype PPC-2 and GPC-1, and this can be transferred to
horticulturally desirable varieties through backcross breeding. The χ2 value indicated
a good fit for segregation of parthenocarpy (early, late and non-parthenocarpy) in the
F2 population and backcrossed populations confirmed with the expected ratio of
1:2:1 and 1:1, respectively. These data support that parthenocarpic trait in cucumber
is controlled by incompletely dominant gene.
In present experiment a linkage map of seventeen SSR markers along with
the F locus covering 100.4 cM distance was developed. The F locus was flanked by
five linked SSR markers viz., SSR13251, UW020605, SSR11798, SSR007281 and
UW084131 were located at 1.0, 4.5, 5.9, 5.0, and 7.0 cM distances respectively. SSR
13251 was the closest markers flanking the gynoecious (F) locus at a distance of 1.0
cM, which will be a critical useful application in marker assisted breeding for
selection of stable gynoecious lines with high efficiency. Hence, identification of
tightly linked SSR markers would be of enormous potential in the context of
developing Indian gynoecious cucumber lines through marker assisted backcross
breeding.
103
सार
खीरे में स्त्रील िंगी, अलिषेक फ ि एविं उपज सम्बिंलित क्षणों का अध्यि, िामक शीषषक स
Description
T-9638
Keywords
null