Genetic analysis of japonica x indica recombinant inbred lines and characterization of major fragrance gene by microsatellite markers

Abstract

Traditional basmati rice varieties are very low yielding due to their tendency to lodging and increasing susceptibility to diseases. To improve the characters of basmati rice variety and study the inheritance of various physio-morphological and quality characters, F5 population comprising of 204 lines from the cross between NPT II (non-aromatic, japonica) and Taraori Basmati or HBC19 (aromatic, indica), were evaluated. Ample amount of genetic variability was observed for the characters plant height, tillers per plant, kernel length, kernel breath and L/B ratio. The grain yield/plant showed positive correlation with productive tiller/plant and test weight. Path coefficient analysis showed that the productive tiller/plant and test weight contribute to grain yield/ plant through direct effect. The parent off-spring regression was high for all the characters under study suggesting improvement of these characters by mere selection. Based on divergence study, 204 lines were categorized in seven clusters whereas parents were grouped in different clusters. Molecular restricted selection using specific SSR markers with depicting high correlation with aroma could offer great promise to select high yielding rice among high aroma lines. A total of 54 randomly selected F5 plants were subjected to SSR marker analysis using SSR markers. The F₅ plants had an allele from either of the two parental lines (homozygous condition) or alleles from both the parental rice varieties (heterozygous condition). At some SSR loci, new/recombinant alleles were observed, which indicate the active recombination between genomes of two rice varieties and can be used for linkage mapping once complete homozygosity is achieved. SSR allelic profile based on two dimensional principal component analysis demonstrated high level of diversity among parents and F5 plants spread between them.

Keywords: Oryza sativa L., basmati, microsatellite, phenotyping, rice, recombinant inbred lines (RILs)

African Journal of Biotechnology Vol. 12(32), pp. 5022-5028