Convergent breeding for new plant type in rice(Oryza sativa L.)

Abstract

The present study on “Convergent breeding for new plant type in rice (Oryza sativa L.) was carried out under the Department of Plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara. This study was carried out for 23 characters in six lines and four testers, and their hybrids developed through a line x tester mating design and was aimed at identification of donor parents for the development of new plant type, and evaluation of the nature of gene action involved in the expression of quantitative traits. In the experiment combining ability, heterosis, character association and gene action involved were estimated. The analysis of variance was significant for almost all the traits under study. Combining ability analysis revealed constantly higher magnitude of SCA variance compared to GCA variance suggesting the preponderance of non additive gene action. Based on mean performance and gca effects Mattatriveni, Kanchana, Jyothi, Gouri ,Swarnaprabha, Mahsuri and Ponmani were identified as best parents which can be utilized in the crossing programme for the development of rice varieties having high yield potential. Among the hybrids Mattatriveni x Ponmani and Mattatriveni x Mahsuri were identified as superior cross combinations based on mean performance, sca effects and standard heterosis and they can be exploited in the creation of new plant type. Characters viz., panicle weight, panicle length, grains per panicle, plant height, 1000 grain weight, total dry matter, grain density and root length which showed significant positive correlation also recorded positive direct effect on grain yield revealing improvement of these characters can directly increase grain yield. Varieties which can be used as donor parents for these characters were identified. Since combination of desirable characters cannot be achieved through one generation of breeding further evaluation and back crossing with specific donor parents is suggested as future line of work.