Gene effects and genetic analysis of indigenous land races and improved cultivars for yield and yield components in rice (Oryza sativa L.)

Rice is one of the crucial staple food crops and its unique grains assist to hold two third of world population. Generation mean analysis is commonly used in studies of inheritance of quantitative traits. Experimental material consisted of ten parents which included six high yielding varieties used as female parents and four traditional landraces used as male parents, F₁, F₂ and F₃generation of six crosses viz., IR 72 x Veeradangan, ADT 39 x Kavuni, ADT 45 x Kavuni, ADT 43 x Navara, ASD 16 x Navara and TPS 4 x Kathanellu. Seven biometrical characters indicated that additive and dominance x dominance gene actions were predominant with duplicate type of gene action for five biometrical characters viz., plant height, number of productive tillers per plant, panicle length, number of filled grains per panicle and single plant yield. The epiststic effects, additive x additive [i] and dominance x dominance [h] were highly significant in most cases. The signs of (h) and (l) were opposite in all studied traits for most crosses. Non-allelic gene interaction was operating in the control of genetic variation in most studied traits. Also, the inheritance of all studied traits was controlled by additive and non-additive genetic effects, but dominance gene effects play the major role in controlling the genetic variation of the most studied traits. Present study indicated that early generation selection is effective and should be practiced for future breeding program.

Genetic systems that control the expression of quantitative traits (Generation mean analysis) to facilitate the choice of the most efficient breeding and selection procedure.

To estimate the gene action for different yield contributing characters.

Dominance and epistatic gene interactions were predominant. Dominance x dominance gene interaction was prevalent.