QUALITY AND GENETIC EVALUATION OF SOME GENOTYPES OF RICE (Oryza sativa L.) USING DIALLEL METHOD

ABSTRACT
The patterns of gene effects on agronomic and some quality traits of eight genotypes of
rice (Oryza sativa L.) and their progenies were studied using Diallel analysis method 1
involving parents, F1 hybrids and their reciprocals. The eight genotypes studied were
selected for their agronomic performance and protein content from thirty genotypes
evaluated in a randomized complete block design and replicated three times at the
Teaching and Research Farm of the Federal University of Technology, Owerri, Nigeria
during the planting seasons of 2005 and 2006. The results of the Diallel analysis
conducted during the 2007 planting season indicated larger magnitude of additive
components of variance in attributes like number of tillers per plant, number of days to
anthesis, panicle length , number of secondary branches per panicle, 1000-seed weight,
grain width and grain length/grain width ratio. Non-additive variance was more important
for plant height at flowering, number of seeds per secondary branch of panicle, grain
length and percentage protein content. The nature and magnitude of general combining
ability(GCA) and specific combining ability(SCA) effects, as well as the direction of
heterosis assessed by the SCA effects, seemed to differ for different traits and various
cross combinations. No parental line consistently had negative SCA effects for all the
traits.