Genetic Studies of Response to Mature Embryo Culture and Relationship with Agro-Morphological Traits and Molecular Markers in Wheat

Five concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and three combinations of indole-3-acetic acid (IAA) and benzyl-amino purine (BA) were used to analyze response to mature-embryo culture for six genotypes of wheat (Triticum aestivum L.) The differences between genotypes as well as between the concentrations of hormones were significant for three tissue culture traits, namely callus formation (C.%), embryogenic calli (E.C.%) and plant regeneration per embryogenic callus (No. Sh/E.C.). Murashige and Skoog basal medium (MS) supplemented with 7 mg/L 2,4-D showed the highest percentage of callus formation while the highest percentage of embryogenic calli (% of E.C.) was obtained on MS medium supplemented with 4 mg/L 2,4-D. MS medium containing 0.1 mg/L IAA and 1 mg/L BA exhibited the highest number of plant regeneration (No. Sh/E.C.). A half diallel mating was designed to produce 15 crosses among six genotypes. Mean square of the diallel analysis of variance indicated highly significant differences among the parents and F1 hybrids for E.C.% and No. Sh/E.C. traits. The results revealed that Lin-6 (P4) was the best combiner for E.C.% and No. Sh/E.C. Estimates of narrow-sense heritability were 83.1% and 69.0% for E.C.% and No. Sh/E.C., respectively. The genetic diversity among six wheat genotypes was analyzed using three tissue culture traits, 10 agro-morphological traits and three molecular marker systems. The Mantel test showed a positive and significant correlation between tissue culture traits studied and each of agro-morphological traits and molecular marker systems.