GENETIC VARIABILITY AND ASSOCIATION ANALYSIS IN SLENDER GRAIN RICE (Oryza sativa L.)
Loading...
Date
2005
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
AAU, Anand
Abstract
Rice (Oryza sativa L.) is one of the most important staple food crops of the world. The nature and magnitude of genetic variability, interrelationships and direct and indirect effects were studied for different yield and quality traits, in different genotypes of slender grain rice. The experiment comprised of slender grain rice, sown in randomized block design with two replications. It was conducted at Main Rice Research Station, Anand Agricultural University, Nawagam, during kharif 2004. Genetic variability, correlation and path coefficient analysis were studied for 25 characters viz., days to 50% flowering, number of tillers per plant, plant height, panicle length, grain yield per plant, 1000-grian weight, hulling per cent, milling per cent, head rice recovery, grain length, grain breadth, grain L/B ratio, kernel length, kernel breadth, kernel L/B ratio, kernel length after cooking (KLAC), kernel breadth after cooking (KBAC), kernel elongation ratio (KER), breadth expansion ratio (BER), water uptake (WU), volume expansion ratio (VER), amylose content, protein content, alkali spreading value (gelatinization temperature) and cooking time. The analysis of variances revealed significant differences among the genotypes for all the characters. All the traits exhibited predominance of genotypic variance in total variance and the magnitude of heritability (broad sense) was also high. Moderate estimates of genotypic coefficient of variances were observed for grain yield per plant, 1000-grain weight, head rice recovery and grain L/B ratio; while the quality components like kernel L/B ratio, breadth expansion ratio, water uptake, alkali spreading value (gelatinization temperature) and cooking time recorded moderate to high genotypic coefficient of variances High genetic advance (% of mean) coupled witli liigli heritability, were observed for agro-morphological traits viz., plant height, grain yield per plant, 1000-grain weight and grain L/B ratio; whereas the quality traits viz., kernel L/B ratio, breadth expansion ratio, water uptake, alkali spreading value (gelatinization temperature) and cooking time also showed similar trend. Most of the remaining traits recorded moderate genetic advance coupled with high heritability. The characters like grain yield per plant, test weight, head rice recovery and grain L/B ratio exhibited moderate genotypic coefficient of variances, with high heritability and high genetic advance. Parallel trend was observed for the quality characters like kernel L/B ratio, breadth expansion ratio, water uptake alkali score (gelatinization temperature) and cooking time; which indicated the better scope for improvement of these traits by an effective selection programme. The correlation coefficient analysis indicated significant and positive association of grain yield with plant height and grain breadth. Interrelationships among important yield components viz., panicle length, 1000-grain weight and grain length was also noticed. Hulling and milling per cent exhibited significant positive association with each other and with water uptake and volume expansion ratio. Kernel length an important from traders' viewpoint, showed association with grain length, grain L/B ratio, kernel L/B ratio and kernel length after cooking. The quality components like kernel elongation ratio and water uptake showed significant positive association with kernel length after cooking. The protein percent showed negative correlation with water uptake; while alkali score (GT) and water uptake were positively associated. Alkali score (gelatinization temperature) and cooking time showed strong positive association. The path analysis with grain yield as dependent variable, indicated that the high direct effects were observed for plant height, grain length and head rice recovery; while the indirect effects were predominant for panicle length, test weight and grain breadth. The path analysis for quality components with kernel length after cooking, showed high direct effects of kernel length and kernel elongation ratio; whereas selection for kernel L/B ratio, water uptake, alkali score (gelatinization temperature) and cooking time can indirectly improve the cooking quality. Based on mean values of morphological traits the genotypes IET 19004, IET 19035, IET 190037, IET 19044 and IET 19045 were identified as elite genotypes; while IET 19001, IET 19009 and IET 19035 were superior with respect to the pre-cooking quality traits. The genotypes IET 19023, IET 19033, IET 19035 and IET 19036 were superior genotypes based on post-cooking quality traits.
Description
Keywords
PLANT BREEDING AND GENETICS, AGRICULTURE, AN ANALYSIS