Assessment of Genetic Parameter of Variability and Heritability based on Morphological Traits and Disease Parameters for Brown Spot in Rice (Oryza sativa L.)

Cochliobolus miyabeanus is a serious threat to the standing rice crop in context of production and productivity as it results in loss of both grain quality and yield. The pathogen causes brown spot disease in rice which had resulted in two severe famines in past. Hence, in this regard it is imperative to search for new and diverse resistance sources and to evaluate them with respect to genetic variability and inherent genetic potential for various morphological traits including yield and yielding attributing traits and disease estimating parameters for identifying high yielding diverse resistant lines that could be utilized in future breeding programmes aimed at development of superior cultivars against brown spot disease. Keeping this in view this study was conducted at Rice Research Farm, RPCAU, Pusa to evaluate 300 genotypes for rice for various morphological traits and disease estimating parameters along with three checks for disease response in augmented design. All the recommended package of practices was followed along with necessary prophylactic plant protection measures to raise a good crop. Data on different traits and parameters under study were recorded and analysed biometrically to assess the genetic parameter of variability and heritability. The ANOVA showed significant difference among the genotypes for most of the traits and parameters under study which reflects ample amount of variability among the genotypes. Further, the smaller difference between GCV and PCV and higher estimates of heritability and genetic advance as percentage of mean revealed higher percentage of inherent genetic potential in overall variability. The higher estimates of heritability and genetic advance as percent of mean for grain yield per plant and AUDPC suggested that the resistant lines identified in this study can be easily advanced through generation following phenotypic selection for derivation of high yielding resistant lines.