INDUCED POLYGENIC VARIATIONS IN RELATION TO GENE ACTION FOR YIELD AND YIELD COMPONENTS IN SPRING WHEAT

Abstract

Gene action in relation to yield per plant, 1000-grain weight and number of grains per spike was studied in 9 × 9 diallel F1 and F2 populations derived separately from nine elite diverse normal and EMS treated spring wheat cultivars (Triticum aestivum L.em Thell.). Some additive and all dominance components were significant for the three characters, their relative proportions varied from character to character. Preponderance of additive gene action was revealed for 1000-grain weight, whereas prevalence of nonadditive gene action was noted for grain yield and number of grains per spike. The magnitude of the additive component increased considerably in EMS treated F2 populations for 1000-grain weight and grain yield, whereas the EMS treatment increased the proportion of nonadditive components for number of grains per spike. Breeding plans which may effectively exploit both additive and nonadditive components of variances for evolving superior breeding populations of spring wheat have been suggested.