Author : Fateh Shakor, Erfan
ESTIMATION OF COMBINING ABILITY, GENE ACTION AND HETEROSIS IN DURUM WHEAT USING NESTED MATING DESIGN
journal of kerbala university,
Volume 7, Issue 3, Pages 32-44
An experiment was conducted by using the nested mating design involved 15 hybrids and 20 parents (5 male and 15 female) in durum wheat during 2011-2012 at the station of Directorate of Agricultural Researches/Erbil under dry farming conditions using a randomized complete block design with three replications. Some growth characters, grain yield and its components were studied. Genetic statistical analysis were done to estimate general combining ability (GCA) of the parents, genetic variance components (additive and dominance), environmental variance, average degree of dominance, heritability in broad and narrow sense, expected genetic advance, heterosis and correlation coefficients among the characters. The results showed highly significant differences among genotypes for all studied characters. Three parents had a positive general combining ability effect in most characters including grain yield. The additive was greater than dominance genetic variance in most characters. Heritability in narrow sense was high for plant height, spike no./plant, 1000-grain weight and grain yield/plant. The values of average degree of dominance was greater than one for flag leaf area, number of grains/spike and biological yield/plant, while less than unit for spike no./plant. Expected genetic advance was high for plant height, spike no./plant and grain yield/plant and it were moderate for plant height, grain no./spike, 1000-grain weight, biological yield/plant and harvest index, while it was low for flag leaf area. Maximum number of hybrids showed significant positive heterosis for grain no./spike, 1000-grain weight and grain yield/plant . The cross [14 × 3] had the highest positive heterosis for most studied characters including grain yield followed by [8 × 1] and [16 × 4]. Grain yield/plant revealed a significant positive genetic correlation with spike no./plant, grain no./spike, 1000-grain weight and harvest index.