814 AJCS 8(5):814-821 (2014) ISSN:1835-2707 Studies on gene action and combining ability of cytoplasmic-genic male sterile hybrids in pigeonpea [Cajanus cajan (L.) Millsp.] Praveen Pandey 1 *, Dinesh Tiwari 1 , Vankat R. Pandey 1 and Sunil Yadav 2 1 Department of Genetics and Plant Breeding, Narendra Deva University of Agriculture and Technology, Kumarganj, Faizabad-224229 (U.P.) India. 2 Department of Genetics and Plant Breeding, Jawahar Lal Nehru Krishi Vishwavidyalaya, Rewa-486001 (M.P.) India *Corresponding author: pandeypraveen1986@yahoo.com Abstract To recognize proper parents for hybrid pigeonpea inheritance pattern of some polygenic traits was studied. The results showed that estimates of SCA variance were higher than their corresponding GCA variance for all the traits except plant height. The values of average degree of dominance were more than unity (>1) and predictability ratio was less than unity (<1) for all the traits except plant height, signifying non-additive gene action which resulted from dominance, over dominance, epistatic and various other interaction effects. Predominance of non-additive effects specifies that population is heterozygous, as such this type of genetic variance is non- fixable. Hence, heterosis breeding is effective for increasing yield potential of pigeonpea. On the basis of general combining ability, the male lines ICP 2309, NDA 2, NDA 3, NDA 96-6, NDA 98-6 and, ICP 2155 and CMS line NDACMS 1-6A were found most promising parents for yield and its major attributes. The crosses, NDACMS 1-4A x NDA GC 31, NDACMS 1-6A x NDA 5-14, NDACMS 1-6A x NDA 8-6, NDACMS 1-4A x IPA 208, NDACMS 1-3A x NDA 98-6, NDACMS 1-4A x Bahar, NDACMS 1-6A x NDA 96-1, NDACMS 1-4A x Amar had high estimates for parents and good specific combining ability effects, hence, it may be considered for hybrid breeding programme. Key words: Pigeonpea [Cajanus cajan (L.) Millsp.], gene effects, combining ability, GCA and SCA variances. Abbreviations: GCA_general combining ability, SCA_specific combining ability. Introduction Pigeonpea [Cajanus cajan (L.) Millsp.], (2n=2x=22) member of family Fabaceae is an important pulse crop of India. Being a pulse, pigeonpea enriches soil through symbiotic nitrogen fixation and adds organic matter and other nutrients that make pigeonpea an ideal crop for sustainable agriculture (Saxena, 2008). It has been recognized as a good source of vegetarian protein particularly in south Asia where majority of the population depends on the vegetarian food. In addition the multiple uses and roles in sustainable agriculture make pulses a favorite crop of marginal farmers. Productivity of pigeonpea in comparison to cereals is very low and stagnant due to several biotic and abiotic stresses. Over time, traditional long duration types have been continually replaced by short and medium duration varieties. These varieties although improved but low yielding as compared to long duration types. Researchers emphasized genetic improvement of pigeonpea for more than five decades and a number of cultivars were developed (Singh et al., 2005). However, the progress in the genetic improvement of yield has been limited and the improved cultivars failed to enhance productivity of the crop. Therefore, use of an alternative approach such as hybrid technology is necessary to enhance the yield of pigeonpea for ensuring food and nutritional security to the country. Efficient and economic crop improvement scheme refers to the collection of superior alleles into a single population to develop ideal genotype. Development of such genotypes would depend upon understanding of the nature and inheritance pattern of the yield and yield components. Both additive and non-additive gene effects have been reported in inheritance of important traits in pigeonpea. However, plant height, days to flowering and maturity had predominantly additive gene effects (Sharma et al. 1972; Dahiya and Barar 1977; Singh et al. 1983). The non-additive gene effects were more pronounced for grain yield, pods plant -1 , 100-seed weight and protein content (Dahiya and Barar 1977; Reddy et al. 1979; Sidhu and Sandhu 1981, Patel et al. 1987). Compared to other food legumes, breeding of pigeonpea is more challenging because of various crop specific traits and high sensitivity to environmental changes. Grain yield is a complex character that is integrated function of a number of component traits most of which are under polygenic control. Modification in yield must be accompanied by changes in one or more components as pointed out by Grafius (1959). Therefore, selection for yield per se may not be much rewarding unless other yield attributing traits are taken into consideration. The selection of a few parents having high