Abstract:
Twenty one F2 progenies derived from a 7x7 diallel crosses along with parents were evaluated
at experimental site of Sher -e- Bangla Agricultural University for ten yield and yield
contributing traits. Due to significant genotypic effects for all the traits, genetic analyses were
performed on F2 progenies including analyses of combining ability and genetic components.
Out of 21 Fjs, the combinations Nap-20 12x Nap-2022, Nap_2037xNap.-206, Nap-I 79xNap-
206 and Nap-248xNap-2012 showed desirable negative combining ability for the characters
of shorter plant height. Nap_248xNap-179. Nap-2057xNap20I2 were good specilic
combiner for early flowering. The hybrid Nap248xNap1 79 was the best for early flowering.
The cross Nap_2037xNap_2022 was the best for number of primary branches/plant, number of
secondary branches, number of siliquae/plant and yield/plant. The cross Nap-206 x Nap-2057
and Nap_248xNap_2057 were the best for siliqua length and number of seeds/siliqua,
respectively. For 1000 seed weight the hybrids Nap-I 79xNap_2057 combination is best. The
crosses Nap_248x Nap-2022 and Nap_179x Nap-206 were found to be the best for higher oil
content %. The parent Nap-2022 was the best general combiner for early flowering, number
of primary branches/plant. The parent Nap-248 was the best for 1000 seed weight. Two
parents Nap- 179 and Nap-257 were good general combiner for oil content %. On the basis of
avcragc score and rank position, the hybrid Nap2037xNap2022 was the best spccific
combiner for most of the important characters. The mean sum of square due to SCA was
significant for all traits indicating that the non-additive gene actions were predominant for the
expression of these characters. The significant mean sum of square due to GCA was also
observed for the traits indicating that non additive gene actions were also prevailed. The
higher magnitude of SCA variance was observed than that of GCA variance for all the traits.
The Vr-Wr graph indicates over dominance (a>O) for number of primary and secondary
branches per plant, number of seeds per siliqua and oil content. Partial dominance (a>0) was
observed for plant height, days of flowering, number of siliquae per plant, siliqua length,
thousand seed weight and seed yield per plant.
Description:
A Thesis
submitted to the Faculty of Agriculture,
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
GENETiCS AND PLANT BREEDING
SEMESTER: JANUARY- JUNE, 2014
