In order to study the combining ability, genetic parameters and gene actions
of yield, yield components and quality characters in rice, fifteen F2
generation of a 6?6 diallel cross, excluding reciprocals, was grown in a
randomized complete block design (RCBD) with three replications. The results
of analysis of variance showed significant differences between the genotypes
for grain yield (GY), 100-grain weight (HGW), number of panicles per plant
(PN), panicle length (PL), number of full grains per panicle (FGN) and for
quality characters including amylose content (AC) and gel consistency (GC).
The results of combining ability analysis revealed that general combining
ability (GCA) and specific combining ability (SCA) were significant for
characters GY, FGN, GC, AC, HGW and PN indicating the involvement of additive
and non-additive effects in their inheritance, however high amounts of Bakers
ratio remarked that additive gene effect had more portion in controlling
these traits. The best combiners for GY, HGW, FGN, PN and PL, were RI18447-2,
IR 50, Daylamani, RI18430-46 and Daylamani respectively. For AC and GC, the
best combiner was Daylamani. Hayman's graphs showed that regression line
passed below the origin cutting Wr axis in the negative region for HGW, PN,
PL and GC, indicating the presence of over dominance. Estimates of genetic
parameters showed significant amount of H1 and H2, and non-significant amount
of D for the characters GY, PN, PL and GC, which confirmed the existence of
dominance in the inheritance of these traits.
Combining Ability Analysis , Estimation of Heterosis and Some Genetic Parameters Using Half Diallel Cross in Bread wheat (Triticum aestivum L.)
