Genetic assessment of some phenotypic variants of rice (Oryza spp.) for some quantative characters under the Gangatic plains of West Bengal
Twenty two (22) recombinant inbreed lines (RIL’s) derived from interspecific cross derivative of Oryza sativa and Oryza rufipogon along with two local check varieties MTU 7029 and Ranjit were evaluated in randomized block design (RBD) with two replications at two different environments (1st at Regional Research Station, New Alluvial Zone (NAZ), Bidhan Chandra Krishi Viswavidyalaya, Sub-Centre, Chakdah, Nadia, West Bengal during Kharif season 2009 and 2nd at Instructional Farm, Bidhan Chandra Krishi Viswavidyalaya, Jaguli, Nadia, during Kharif season 2010), to study the polygenic variations in yield for yield and its attributing characters and their cause and effect relationship. The analysis of variances revealed the significant differences among the 24 genotypes against all the characters except panicle weight, grain length, grain breadth and grain L/B ratio. The magnitude of phenotypic coefficients of variation (PCV) was higher than genotypic coefficients of variation (GCV) for all the characters suggesting the influences of the environmental forces on the expression of these characters. High PCV and GCV values were observed in grain yield per plant, 1000 grain weight, L/B ratio, grain breadth and panicle weight. High heritability coupled with moderate to high genetic advance as percent of mean for plant height, panicle weight, grain length, grain L/B ratio, 1000 grain weight and yield per plant while low heritability estimates along with low genetic advance were observed for fertility percentage and florets number per panicle. In general, genotypic correlation coefficients were higher than their corresponding phenotypic correlation coefficients. Path coefficient analysis revealed that number of characters chosen was very much appropriate as evident from low value of residual effect. Maximum positive direct effect was imparted by number of gains per panicle followed by grain L/B ratio, days to 50% flowering and panicle length respectively. Florets number per panicle imparted the maximum negative direct effect followed by grain breadth, fertility percentage and panicle number per plant. Per se performance revealed that two lines viz; KS-7 and KS-13 were promising in respect of grain yield and some other yield related traits. Number of grains per panicle and floret number per panicle give significant positive correlation with yield.
Key words: Correlation, genotypic coefficients of variation, genetic advance, heritability, phenotypic coefficients of variation, rice, recombinant inbreed lines.