Genetic Studies and Response of Rice Germplasm (Oryza sativa L.) to Brown Spot Incidence in Aerobic Condition

Abstract

The present investigation was carried out with 150 rice genotypes and three check varieties namely Rajshree, Pankaj and Rajendra Neelam with the view of assessing the variability in traits related to productivity and studying the response of these varieties towards brown spot resistance under the aerobic condition. These genotypes were evaluated for brown spot incidence and yield potential by recording observation for 11 quantitative traits by using augmented randomized complete block design at Rice research farm of RPCAU, Pusa, Bihar, during Kharif season of 2019.  Analysis of variance revealed significant differences amongst the genotypes for all the eleven traits studied. Based on the mean performance, 14 genotypes out of 150 genotypes were significantly superior to the best check, Rajendra Neelam, for three traits viz., grain yield/ plant, Percent Disease Intensity (PDI) and area under disease progress curve (AUDPC), which are considered key traits for the assessment of brown spot incidence.  The genotypes viz., VLD 16 entry no. -5, Udyagiri entry no.-9, and SKL 6 entry no.-94 significantly exhibited high mean for majority of the traits under study. Based on the AUDPC values, genotypes Satabdi, PS-4, Haryana Basmati and SKL6 were resistant for brown spot incidence. For most of the traits studied, moderate to low value of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) was recorded.  Higher magnitude of broad sense heritability and genetic advance as per cent of mean (GAM) were perceived for days to 50% flowering, plant height, no. of tillers per plant, no. of panicles per plant, filled grains per panicle, grain yield per plant, PDI, AUDPC signifying that direct selection by these traits can be rewarding for achieving yield improvisation and resistance to brown spot disease