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Breeding for yield and its components some pred wheat crosses ( triticum aestivum )
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Abstract: A half diallel cross among seven common wheat varieties and lines were evaluated in both F1 and F2 generations in Etay El-Baroud Agricultural Research station during the three successive seasons ,2003/2004,2004/2005 and 2005/2006 to study some breeding parameters. The experimental design of randomized complete blocks with three replications was used . Seven characters were studied ,i.e. plant height (cm.),spike length (cm.) , number of spikes per plant , number of kernels per spike ,1000 kernels weight (g) , grain yield /plant (g) and total plant Weight .
Test of significance indicated that the mean squares of genotypes were highly significant for the plant height, number of spikes/plant, spike length, number of kernels/spike, 1000- kernels weight and grain yield/plant in F1 and F2 generations. The significance of the mean squares indicated the presence of true differences among these genotypes . Mean squares due to parents and crosses were highly significant for all traits in F1 and F2 generations except number of spikes /plant in the F2 generation.
Parents vs crosses mean squares as an indication to average heterosis overall crosses were found to be highly significant for all traits studied in F1 and F2 generations except number of spikes/plant, spike length, 1000 kernel weight and grain yield /plant in the F2 generation.
The analysis of variance of general combining ability (GCA) and specific combining ability (SCA) values mean squares were found to be highly significant for all studied traits in the F1 and F2 generations, Also GCA/SCA variances were found to be greater than unity for all studied traits except number of spikes /pant in the F1 hybrid , indicating that additive and additive x additive types of gene action were of greater importance in the inheritance of all characters studied .
The additive variances (D) were significant for all traits, except number of spikes/plant and 1000 grains weight in the F2 and grain yield /plant in the F1 and F2 generations. These results indicated that the additive gene effects played a major role in the inheritance for all traits in F1 and F2 generations. Dominance components of variation (H1) were highly significant and greater than D also, for all traits in both generations.The component of variation due to the dominance effects associated with gene distribution (H2) was highly significant and greater than D for all traits in F1 and F2 generations. All H2 values were smaller than H1 values for all traits indicating unequal allele frequency. The overall dominance effects of heterozygous loci (h2) were significant for all traits in F1 and F2 generations except for plant height in F1 and F2, and number of spikes /plant, 1000 kernel weight and grain yield /plant in the F2 generation.The covariance of additive and dominance (F) was not significant for all traits in F1 and F2 generations except plant height in the F2 ,number of spikes/plant in the F1 and number of kernels /spike in the F1 and F2 generation.The relative size of (D) and (H1) estimated as (H1/D)1/2 can be used as a weight measure of the average degree of dominance at each locus, showed the presence of over dominance for all traits in both generations. .
Low heritability values in narrow sense were detected for all traits in both generations except spike length and 1000 kernel weight in the F1 and F2 generations which gave high value
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| Publication year |
2006
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| Pages |
322-335
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| Availability location |
معهد بحوث المحاصيل الحقلية- 9شارع الجامعة- الجيزة
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| Availability number |
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| Organization Name |
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| serial title |
ALEXANDRIA SCIENCE EXCHANGE JOURNAL
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| Author(s) from ARC |
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| Agris Categories |
Agricultural research
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AGROVOC
TERMS |
Triticum aestivum.
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| Publication Type |
Journal
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