Revista de fisiología y patología vegetal

Combining Ability of Agronomic and Yield Traits in Rice Genotypes

Sheila Rono, Felister Nzuve, James Muthomi and John Kimani

Combining Ability of Agronomic and Yield Traits in Rice Genotypes

The demand for rice production in Kenya is high while production has remained far below consumption demand for quite a number of years. Growing of poorly adapted rice varieties with undesirable traits is one of the major factors limiting production. The objectives of this study were to determine the performance and combining ability of rice cultivars for both agronomic and yield related traits. Seven genotypes were crossed in a North Carolina II mating design to generate the F1 hybrids. The 12 F2 seeds, 7 parents and 1 check variety were planted at KALRO-Mwea following a randomized complete block design replicated three times. Analysis of combining ability was done using SAS (Version 9.3) software. Rice genotypes were significantly different for all the agronomic and yield traits except chlorophyll content, filled grains and thousand grain weight. The mean square GCA (m) were significantly different for all traits except chlorophyll content while for GCA (f) except productive tillers, panicles per plant and thousand grain weight. Specific Combining Ability showed significant differences for all traits measured. The heritability results indicated that these traits were governed by nonadditive genes. The parents, Komboka, Mwur 4 and Nerica 4 were good general combiners for grain yield, filled grains and had shorter duration to flowering. These parents could be used in a hybridization program to introgress yield traits into adapted low yielding lines. The best specific combiners were hybrids generated from a cross between Mwur 4 and Nerica 4 and Komboka and Nerica 4. These hybrids could be exploited for heterosis breeding.