Construction Of Selection Index Using Simple Correlation Coefficients And Path Coefficients (Direct Effects) As A Weight In Rice (Oryza Sativa L.)

The present study was conducted with sixty three diverse genotypes of rice (Oryza sativa L.) at Main Rice Research Station (MRRS), Nawagam, Gujarat during kharif season of 2011 to assess the relationship and selection index among yield and yield attributing characters. Total six characters were used for construction of selection indices i.e. Grain yield per plant, plant height, panicle length, number of productive tillers per plant, 1000 grain weight and harvest index. Two different weight methods were used for this study like simple correlation coefficients and path coefficients (Direct effects). The analysis of variance revealed that the presence of considerable amount of variation among the test of genotypes for all the characters. The simple correlation study revealed that harvest index, number of productive tillers per plant and 1000 grain weight had positive and highly significant correlation with grain yield per plant. The path analysis results showed that number of productive tillers per plant had the highest direct effect on grain yield per plant followed by 1000 grain weight, harvest index, panicle length and plant height. Results of selection indices showed that a progressive increase in the efficiency of selection was observed with the inclusion of additional character in the selection index. Selection index (I123456) which was combinations of grain yield per plant, plant height, panicle length, number of productive tillers per plant, 1000 grain weight and harvest index had highest per cent relative efficiency (PRE) among all the indices including rice grain yield per plant for simple correlation coefficients and path coefficients weight method. Looking to simplicity, selection index (I256) which was combinations of plant height, 1000 grain weight and harvest index showed highest PRE and it was suggested to use for selection of genotypes for rice grain improvement without grain yield per plant.