Genetic analysis for heterotic traits in bread wheat (Triticum aestivum L.) using six parameters model.

The assessment of nature of gene effect for yield and its contributing traits and detection of epistasis in wheat was studied in five crosses involving seven parents through generation mean analysis. Scaling test and joint scaling test were showed significant for almost traits all crosses. Additive gene effects (d) were positively significant for days to maturity and tillers per plant in cross II; for seed per plant in cross IV. Dominance gene effects (h) were highly significant for days to 75% heading in cross II, III and IV; for days to maturity and grains per spike in cross II, for grain yield per plant and grains per spike in cross I. Additive x additive type of gene (i) were positive significant effect for days to 75% heading in cross II, III and IV; for days to maturity in cross II and grains per spike in crosses I, II; for 1000 grain weight in cross II and IV; for grain yield per plant in cross I. Additive x dominance type of gene effect (j) was positive significant for days to 75% heading in cross III; for days to maturity in cross II and III; for plant height in cross III; tillers per plant in cross II; for grain per spike and seed per plant in cross III and grain yield in cross IV. Dominance x dominance effect (l) were positively significant for days to 75% heading, plant height in cross I; for plant height in cross III, IV and V; for tillers per plant in cross II and for grains per spike in cross IV and V; seed per plant, grain yield in cross IV. Therefore, it has been suggested that selection of studied characters based on different gene action of generation mean to be used further crop improvement through ideal breeding programme. [ABSTRACT FROM AUTHOR]