Assessment of Genetic Variability for Yield and Yield Contributing Characters in Rice (Oryza sativa L.)

The study was conducted at the department of Genetics and Plant Breeding, Patuakhali Science and Technology University, Bangladesh during the period from April 2018 to August 2018 to study variability, heritability, genetic advance, interrelationship among 14 important characters among the 15 popular rice genotypes of Bangladesh. Significant variation in plant height of BRRI dhan43, in 50% flowering BRRI dhan42 and BRRI dhan43, for days to maturity BRRI dhan42 and BRRI dhan43, for number of unfilled grain per panicle BRRI dhan48, for flag leaf length Lakhi Lata, for flag leaf width Lohar Gura, for panicle plant-1 BRRI dhan27, for number of filled grain per panicle Kalo Jamvi, number of filled grain per panicle Lakhi Lata, for 100-grain weight BRRI dhan48, for yield plant-1 BRRI dhan48 were found. Besides, yield per plant and 100-grain weight showed high genotypic and phenotypic co-efficient of variation while other characters showed moderate genotypic and phenotypic co-efficient of variation, except days to 50% flowering, days to maturity, panicle length, flag leaf length, flag leaf width, dry matter, and harvest index. All but, plant height and spikelet per panicle, all other characters studied in this experiment showed high heritability and high genetic advance in percent of mean. Panicle per plant, no. of filled grain, 100-seed wt., and harvest index are positively correlated. Yield per plant is also significantly and positively correlated with flag leaf length at the genotypic level but non-significant at phenotypic level. Grain yield showed non-significant positive association with flag leaf width and panicle length. Above information suggests that yield per plant would increase with increase of these characters. Path co-efficient analysis suggested that flag leaf length, panicle per plant, and flag leaf width showed moderate to low direct effect, but 100-seed weight showed highest positive direct effect toward yield per plant. Plant height showed a low negative direct effect on grain yield per plant while days to maturity, panicle length, no. of filled grain, no. of unfilled grain per panicle and dry matter had considerable negative direct effect on grain yield per plant and showed a negligible indirect effect. Thus, selection based on maturity period, number of panicles per plant, panicle length and higher number of filled grains per panicle might be effective for improving yield of rice.