Selection indices for yield and yield contributing characters in slender grain rice genotypes

Since grain yield is a complex trait, controlled by non-additive gene action and is believed to have low heritability, hence direct selection for grain yield per se is often not reliable and effective. Further intergenotypic competition and a large experimental error associated with yield measurements often bias the outcome of selection for higher yield. Therefore, several workers in different crop plants have emphasized the importance of indirect selection for yield through the use of component traits governed by genes with additive effect and with strong correlation on grain yield. As no single trait could be taken as an adequate criterion of selection for yield, therefore, selection indices provide a useful method by making use of several correlated traits for greater efficiency of selection in yield. Selection indices study revealed that the thirteen character index was superior over the direct selection for yield per se. On the basis of thirteen character selection index promising genotypes namely MTU110, RTN28-1-5-3-2, CB12186, NP3003, WGL-821, RGL7011, R1130-80-1-52-1, GNV-14-25, CR3511-3-2-2-5-1, BPT2675, NLR3337, RGL7012, BPT2595, NLR3350, RP5947-123-6-2-1-1-B, AD12074, MLR3313 and RP5949-122-2-5-1-1 may be used for future breeding programme. It was interesting to note that the relative rankings of varieties selected on the basis of per se performance and index score differed indicating the importance of selection index over direct selection on grain yield.