Combining ability for grain yield and its components in lowland rice (Oryza sativa L.)

Abstract

Rice (Otyza sativa L.) is the most important food-crop of India, occupying 44.5 m.ha. with a total production of 85.5 m.t. (2000-2001) with an average productivity of 1.9 tlha. Of the total area 13.0 m.ha. (35%) is under rain-fed lowlands, where the average yields are around 1.2 tlha. Under this situation farmers are some times forced to go for late planting due to unpredicted rainfall. Hence, there is a need to develop varieties with high yield and also suitable for late planting. The success of a plant breeding program largely depends on the choice of parents for hybridization and identification of superior recombinants in the segregating generations. The combining ability analysis developed by Griffing [1] provides useful information on selection of different parents, which in turn helps the plant breeder to identify most promising crosses for further use in breeding program. The present investigation has been, therefore undertaken to study combining ability for grain yield and its components in lowland rice under normal and late planting situations.