Inheritance of Induced Glaucousness, Grain Yield, and Yield-Related Traits in Bread Wheat (Triticum aestivum L.)

Abstract

Glaucousness is the grayish or whitish appearance of leaf blades, sheaths, glumes and stems of plants. This appearance is due to the epicuticular wax exudates produced by plant organ. Inheritance of glaucousness has been previously reported in bread wheat (Triticum aestivum L.) (Jensen and Driscoll, 1962; Stuckey, 1972; Liu et al. 2007) and in durum wheat (Clarke et al., 1994). Chromosome 2B in wheat cultivar Chinese Spring was first shown to bear a gene for the production of glaucousness by Muramatsu (cited in Driscoll and Jensen, 1964). Chromosome 2D was found to bear a hypomorph of 2B for glaucousness. Two dominant inhibitors of these two genes were also located on 2B and 2D. Chromosome 3A bears the most effective gene for glaucousness of the peduncle (Stuckey, 1972). However, a gene for spike glaucousness, WS, was mapped distally on chromosome 1BS of wild emmer wheat (Peng et al., 2000).
Genetic studies on the inheritance of glaucousness in wheat indicated that glaucousness is dominant to nonglaucousness (Tsunewaki, 1966; Stuckey, 1972; Clarke et al., 1994). However, other studies by Jensen and Driscoll (1962) and Liu et al. (2007) demonstrated that nonglaucousness is controlled by a single dominant gene. In addition, the evidence of additive gene action influencing glaucousness was also reported in bread wheat (Stucky, 1972) and durum wheat (Clarke et al., 1994).
Number of spikes/plant, number of kernels/spike and kernel weight are the major components of grain yield in wheat. Due to their importance, the inheritance of grain yield and its components in wheat have been previously studied (Singh et al., 1986; Sidwell et al., 1976; Sun et al., 1972; Hsu and Walton, 1970).
Dominant genetic variance was found to play an important role in the inheritance of number of ears/plant and yield/plant (Hsu and Walton, 1970). However, Singh et al. (1986) found that additive genetic variance for grain yield, grains/spike, and seed weight was much more important than dominance variance. While, Sidwell et al. (1976) reported that additive and dominance variances were much smaller than environmental variance for grain yield and its components except for kernel weight.
Yield component breeding to increase grain yield would be most effective if the components involved were highly heritable, genetically independent or positively correlated, and physiologically unrelated or related in a positive manner (Sidwell et al., 1976; Fonseca and Patterson, 1968).