Studies on Combining Ability, Heterosis and Inbreeding Depression in Forage Sorghln (Sorghum Bicolllr L. Moench)

Abstract

Thesis Title: "Studies on combining ability, heterosis and inbreeding depression in forage sorghum (Sorghum bicofor L. Moench)". A complete set of material consisting of 100 tre~tments (10 par~nts, 45 FIS and 45 F2S) were evaluated in a completely Randotruzed Block Design (RBD) with three replications during Kharif 2013. Both additive and non additive components of genetic variation appeared imponant in the expression of almost all the characters. For exploitation of both the additive and non additive component of variation, material may be handled through pedigree method and modified recurrent selection for obtaining superior segregants and genotypes. Promising parents viz., HC 171, UP chari 2, Pant chari 5 and Pant chari 6 which were having high general combining ability effects in desirable direction for green fodder yield and yield components character like plant height, leaf breadth, leaf length and stem girth may be incorporated in crossing programme to have better genotypes for better green fodder yield. The cross combinations namely, UP chari 2 x HC 171 , Pant cbari 5 x RSSV 9, Pant chari 5 x SSG 59-3, SSG 59-3 x Pusa chari 23, CSV 15 x Pant cbari 6. G 48 x HC 171. CPVI 1724 x HC 171 and Pant chari 5 x G 48 which exhibited good specific combining ability effects for green fodder yield and its contributing traits such as days to 50% flowering, leaf breadth, leaf length, leaves per plant, leaf stem ratio and stem girth in both F 1 and F2 generations. These cross combinations may be exploited for development of hybrid in forage sorghum or may be incorporated in multiple cross breeding programme to have better transgressive segregants with broad genetic base for the selection in forage sorghum improvement programme. Nine cross combinations which revealed highest value of heterosis for leaves per plant and green fodder yield viz.. SSG 59-3 x CSV 15, Pant cbari 5 x CSV 15, RSSV 9 x HC 171, CSV 15 x UP chari 2. G 48 x UP chari 2. Pant chari 5 x HC 171, G 48 x HC 171, Pant chari 6 x CPVI 1724 and SSG 59-3 x Pusa chari 23 over better parent as well as economic parent may be exploited for developing hybrids for better yield in forage sorghum. Five crosses namely, Pusa chari 23 x G 48, Pusa chari 23 x CPVI 1724, Pant chari 5 x UP chari 2, Pant chari 5 x G 48 and Pant chari 6 x CPVI 1724 exhibited significant negative inbreeding dep~ssion _in both the gener~tions '~th additive type gene interaction may be suggested for mcreasmg green fodder ytel~. H1gb heritability for plant height, leaf breadth, leaves per plan~, leaf area, leaf_stem_ ra110. ste?J girth and green fodder yield in both F1 and F2 ge~erauo~s co~pled WI~ high ~en:uc advance may be used as direct selection criteria for unprovmg yteld and Its contnbuung traits.