Abstract:
Twenty seven genotypes of sweet gourd (Cucurbita rnoschasa L.) were studied in a field
experiment at the experimental field of Sher-e-Bangla Agricultural University. Dhaka,
during March 2010 to September 2010. Among them, six genotypes did not germinate.
Sweet gourd is a nutrient powerhouse, low in fat and calories and rich in disease fighting
nutrients such as a-carotene, 13-carotene, fiber. vitamin-C & E. K. Mg. pantothenic acid.
There are significant quantities of the carotinoids like lutien and zeaxanthin, both of
which helps to maintain eye health. It's an important summer vegetable and very
adaptive to climate change. Lack of high yielding, disease and pest tolerant varieties is
the main constrains towards its production. Among the cultivated land races, a wide
range of genetic variability exists in this crop that can be exploited for its improvement.
The objectives of the study were to measure the variability among the genotypes for
yield and yield contributing characters, estimate genetic parameters, association among
the characters and their contribution to yield. This helps to choose desirable parents for
establishing new breeding population. High genotypic co-efficient of variation (GCV)
was observed for fruit yield per plant, number of male flower per plant and number of female
flower per plant. Low genotypic co-efficient of variation (GCV) was observed for days to first
female flowering, days to first male flowering and fruit length. In all cases phenotypic
variances were higher than the genotypic variances. High heritability with high genetic
advance in percent of mean was observed in yield per plant, number of male flower, pedicel
length of female flower, and pediccl length of male flower indicated that these traits were under
additive gene control and selection for genetic improvement for this trait would be effective.
Correlation studies revealed that highly significant and positive association of yield per plant was
found with number of female flower followed by fruit length, number of male flower, fruit
breadth and fruit weight at both genotypic and phenotypic level. Path co-efficient analysis
revealed that maximum direct contribution towards yield per plant with traits of number of
female flower followed by number of male flower and days to first male flowering. The
highest intra-cluster distance was found in cluster V. low in IV and no distance was found in
cluster I. Among six clusters the highest inter cluster distance was observed between cluster H
and cluster Ill and the lowest between cluster IV and cluster V. Considering all the characters the
G21 (BD-2 150), G1 (1313-2151). G11 (BD 2229) and G13 (BD 266) genotypes were selected for
futurc breeding programme.
Description:
A Thesis
Submitted to the Faculty of Agriculture
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfilment of the requirements
for the degree of
MASTER OF SCIENCE
IN
GENETICS AND PLANT BREEDING
SEMESTER: Jan-Jun, 2011