VARIABILITY AND GENETIC PARAMETERS FOR GRAIN YIELD AND ITS COMPONENTS AND KERNEL QUALITY ATTRIBURTES IN CMS BASED RICE HYBRIDS (ORYZA SATIVA L.)
The present investigation was under taken to study the extent of variability and genetic parameters with 16 parents and 48 hybrids for nine yield and its components and twenty five quality characters. The magnitude of difference between PCV and GCV was relatively low for all the traits, indicating less environmental influence. High GCV and PCV were recorded for harvest index, total number of productive tillers per plant and gelatinization temperature in parents and for total number of productive tillers per plant, number of grains per panicle, gelatinization temperature and amylose content in hybrids. High heritability coupled with high genetic advance as per cent of mean were recorded for gelatinization temperature, harvest index, total number of productive tillers per plant, number of grains per panicle, kernel length, kernel L/B ratio and grain yield per plant in case of parents and for gelatinization temperature, amylose content, total number of productive tillers per plant, number of grains per panicle and harvest index in case of hybrids indicating the additive gene effects in the genetic control of these traits and can be improved by simple selection in the present breeding material.
Genetic variability of panicle characters in tall indica aman rice
Thirty five genotypes of tall indica aman rice were evaluated for nine panicle characters under two environments to find out the extent of genetic variability present in the population. The experimental study indicated existence of considerable amount of genetic variability for all the characters studied. Genotypic and phenotypic coefficient of variation were high for unfilled florets panicle-1, grain yield plant-1, panicle number plant-1, grains panicle-1, panicle weight and 1000-grain weight. High estimates of heritability, genotypic coefficient of variation and genetic advance were observed for unfilled florets panicle-1, grain yield plant-1, panicle number plant-1, grains panicle-1, panicle weight and 1000-grain weight. These characters can be effectively improved through selection.
Heterosis for yield and yield components in rice ( Oryza sativa L.)
Eight genetically diverse high yielding rice cultivars selected from clusters formulated through Mahalanobis D2 statistics were crossed in a diallel fashion. The parents and crosses were evaluated and heterosis for yield and its principal components estimated. Results suggest that yield increase was largely due to significant and favourable heterosis in yield components viz., number of spikelets panicle–1, panicle length, leaf area plant-1 (at maximum tillering stage) and number of panicles m-2. Five top heterotic crosses over their mid and better parents for each trait were identified.