Browsing by Author "Kamaluddin"

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Combining ability analysis for grain filling duration and yield traits in spring wheat (Triticum aestivum L. em. Thell.)
(Brazilian Journal of Genetics, 2007) Kamaluddin; Rishi M. Singh; Lal C. Prasad; Malik Z. Abdin; Arun K. Joshi
A diallel analysis of wheat (Triticum aestivum L. em. Thell) parents (n = 11) and their F1 (n = 55) and F2 (n = 55) offspring was carried out for the following four traits: grain filling duration (GFD), GFD for growing degree days (GDD), 1000 seed weight and seed yield per plant. Analysis of variance for general combining ability (GCA) and specific combining ability (SCA) displayed significant F1 and F2 general and specific combining ability effects for the four traits studied. For all the traits the GCA effects were relatively more important than the SCA effects, indicating that additive genetic effects were predominant. Crosses displaying high SCA effects for grain filling duration, seed weight and yield were observed to be derived from parents having various types of GCA effects (high x high, high x low, low x low and medium x low). The single seed descent method can be applied to exploit additive gene effects whereas dominance gene effects could be valuable in hybrid wheat breeding programs. Among the parents, genotypes from the International Maize and Wheat Improvement Center (Centro Internacional de Mejoramiento de Maíz y Trigo, CIMMYT) as well as South Asia were found to be superior general combiners for grain filling duration. Likewise, crosses involving diverse parents from CIMMYT and South Asia showed significant SCA effects for grain filling duration and other traits. Copyright by the Brazilian Society of Genetics.
Inheritance of grain filling duration in spring wheat (Triticum aestivum L. em Thell)
(2007) Kamaluddin; Rishi Muni Singh; Malik Zainul Abdin; Mather Ali Khan; Tanweer Alam; Salim Khan; Lal Chand Prasad; Arun Kumar Joshi
To understand the genetic control of grain filling duration (GFD), i.e., the number of days from anthesis to physiological maturity, we studied the F1, F2, BC1 and BC2 generations of six spring wheat crosses from nine varieties/genotypes. Generation mean analysis for gene effects indicated that one or more types of epistasis were significant in all crosses. In each pairing, the F1 and F2 means were either intermediate or closer to the mean of the parent having the longer GFD. Our narrow-sense heritability estimate was reasonably high, at 47.67 (based on diallel analysis). This demonstrated that progress could be made from the selection in these crosses for either long or short GFD. The two early varieties that had identical maturity durations differed in their GFD values, indicating that maturity dates are not good criteria when choosing parents for modifying GFD. To utilize favorable additive x additive effects during this selection, we suggest that a single seed descent (SSD) or bulk population approach be adopted. In comparison, dominance effects would prove quite useful in hybrid wheat breeding programs.