Combining ability analysis in bread wheat

Abstract

Combining ability analysis was studied in a 10 × 10 half diallel set
of bread wheat (Triticum aestivum L.). The analysis of variance for
combining ability revealed that the mean squares due to both general
combining ability (GCA) and specific combining ability (SCA) were
highly significant for number of effective tillers per plant, length of
spike, number of spikelets per spike, peduncle length of spike, number
of grains per spike, grain weight per spike, 100-grain weight and grain
yield per plant. This indicated that both additive and non-additive
genetics variances played a vital role in the inheritance of all these
eight traits.The GCA and SCA ratio (σ2GCA/σ2SCA) was less than unity
for all the traits indicated that non-additive component play relatively
greater role in the inheritance of all the eight traits.The line, HW 5018
and HI 1544 were good general combiners for grain yield per plant
and some of its component traits. Nine crosses exhibited significant
and positive SCA effects for grain yield per plant. The highest SCA
effect for grain yield per plant was exhibited by the cross HW 5018 x
K 604 followed by RAJ 4136 x UAS 281, KYZ 300 x RAJ 4136, KYZ 300
x HW 5018 and GW 173 x RAJ 4136. The cross KYZ 300 x RAJ 4136
was found most promising having high SCA effect together with per
se performance for grain yield per plant, number of effective tillers
per plant, grain weight per spike and 100-grain weight which could
be further exploited in practical plant breeding programme.