Genotype x environment interaction in commercial rice (Oryza sativa L.,) hybrids

Abstract

The present study on “Genotype x Environment interaction in commercial rice (Oryza sativa L.) hybrids” was carried out under the Department of Plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara. Seven commercial rice hybrids and two check varieties were evaluated for eighteen characters across three farming situations of central zone of Kerala during kharif, 2003. In the experiment, variability, heritability and genetic advance, path coefficients, stability, standard heterosis and inbreeding depression were estimated. Mean performance of hybrids across the locations revealed that, in general hybrids performed better than check varieties with respect to yield and yield attributing characters like grain yield ha-1, straw yield ha-1, number of grains panicle-1, productivity day-1 and productivity plant-1. With regard to grain quality parameters such as 1000 grain weight, milling percentage and head rice recovery, check varieties showed superior performance over hybrids. High variability and heritability was noticed for most of the yield characters. High genetic advance coupled with high heritability were observed for plant height, grain yield ha-1, straw yield ha-1, number of grains panicle-1 and 1000-grain weight. The traits such as days to 50 per cent flowering, plant height, straw yield ha-1, harvest index, number of days to physiological maturity, productivity day-1 and volume expansion ratio can be used for direct selection for yield improvement since they had exhibited significant positive correlation with grain yield. Stability analysis revealed that the hybrid KRH-2, which had recorded highest mean value and regression coefficient less than unity, performed well even under poor management conditions. Therefore KRH-2 can be recommended for general cultivation in central zone of Kerala. For better management conditions, NSD-2 that had responded well to good management, can be recommended. Heterosis studies revealed the presence of significant amount of standard heterosis in most of the hybrids for yield and yield attributing traits. Significant inbreeding depression was also observed for yield and yield attributing characters.