Variation and inter-relationship, between yield and, some agronomic characters in induced rice (<i>Oryza sativa</i> L.) mutants

Abstract

A high yielding, locally adapted cultivar Salama of rice (Oryza sativa L.) which was recommended for cultivation in Tanzania since 1978 was irradiated with gamma rays using two doses (170 & 210 grays) from Cobalt 60 (60C0) in order to shorten the plant height. Twenty three mutant lines in M5 and M6 generations plus two controls were sown in a randomised complete Block Design (RCBD) and replicated three times at the Sokoine University of Agriculture (SUA) farm in Morogoro, Tanzania. The objective of the study was to estimate genetic parameters and the association of various traits with yield. The combined analysis over two years was used to estimate genetic variances heritability and expected genetic gain from selection. The data generated were also used to perform correlation and path coefficient analysis. Analysis of variance revealed significant differences, among the tested genotypes for all the characters tested. Significant genotype X Year interactions were observed for all the characters except number of tillers per plant and 1000 grain weight. High genotype coefficient of variation heritability estimates and expected genetic advance were recorded for plant height number of tillers per plant and 1000 grain weight. Correlation and path coefficient analysis revealed that days to 50% flowering and number of panicles per square metre were important characters that incluenced yield.

Keywords: Agronomic characters, mutants, Oryza sativa, rice varietal-improvement, yield

Tanzania J, Agric. Sc. (2001) Vol. 4 No 2, 83-88