COMPARATIVE STUDY BETWEEN TWO MATING DESIGNS TO ESTIMATE DIFFERENT GENETIC PARAMETERS IN CORN (Zea maize, L.) | ||||
| Journal of Agricultural Chemistry and Biotechnology | ||||
| Article 4, Volume 4, Issue 1, January 2013, Page 29-44 PDF (619.75 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jacb.2013.52997 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| A. M. El-Adl; A. H. Abd El-Hadi; K.S. Kash; M. Z. M. El-Diasty | ||||
| Department of Genetics, Faculty of Agriculture, Mansoura University | ||||
| Abstract | ||||
| In Egypt, as well as many other countries, corn is considered an important field crop. Due to the importance of corn, scientists in all countries gave corn breeding great concern. Many authors obtained high values for heterosis from the F1 maize hybrids. It is found that the amounts of heterosis from the MP % for the diallel cross mating design were: 179.30, 17.78, 51.97 and 52.77% for Ear weight, No. of rows/ear, No. of kernels/row and 100 kernels weight at Mansoura location, respectively. The values of heterosis were: 107.13, 9.06, 31.07 and 65.30% for the same traits at the second location (Sohag), respectively. However, the estimated amounts of heterosis with respect to t BP % were: 152.48, 3.79, 26.36 and 38.7% for Ear weight, No. of rows/ear, No. of kernels/row and 100 kernels weight at Mansoura, respectively. They were: 68.70, -1.32, 23.05 and 51.12% for the same traits at Sohag, respectively. But for the line x tester mating design, it is appeared that the amounts of heterosis from the MP % were: 51.14, 3.20, 11.7 and 44.60% for ear weight, No. of rows/ear, No. of kernels/row and 100 kernels weight at Mansoura, respectively. The values of heterosis were: 121.1, 19.0, 42.6 and 50.17% for the same traits at Sohag, respectively. ًWhile the estimated amounts of heterosis with respect to the BP % were: 26.33, -16.13, 1.92 and 24.32% for ear weight, No. of rows/ear, No. of kernels/row and 100 kernels weight at Mansoura, respectively. They were: 89.7, -4.2, 5.5 and 21.82% for the same traits at Sohag, respectively. GCA and SCA are usually used to estimate the types and the nature of gene action that present within hybrids. In this respect, there are different mating designs are known to obtain the estimates for these two components. Among these mating designs i.e. diallel crosses and line x testers mating designs. These two mating designs yield estimates for both GCA and SCA. The mean squares for GCA at Mansoura were highly significant for No. of kernels/row and 100 kernels weight. In general, the magnitudes of the mean squares at Sohag were larger than their corresponding estimates at Mansoura for Ear weight and No. of rows/ear while, it was the vice versa for No. of kernels/row and 100 kernels weight. The mean squares of the GCA of all yield component traits were larger in their magnitudes than their corresponding estimates of SCA at Mansoura. It is found that the results for the line x tester mating design indicated that the mean squares of GCA were highly significant. Therefore, both additive and additive by additive genetic variance appeared to be the most important and reliable component of genetic variances. The presence of significant estimates of GCA and SCA suggest the importance of either additive (GCA) or non additive gene action (SCA). Indeed, superior hybrids depend on the presence of dominance genetic variance. In the same time, superior hybrids would depend on additive by additive genetic epistasis in case of the absence of the dominance variance. Therefore, it is very important to estimate the two types of gene action. The utilization of two mating designs where used with the same inbred lines. These parental lines were planned to evaluate their validity to estimate both GCA and SCA using the homogeneity test of variance which declared that the estimates of GCA and consequently the additive genetic variance would be more valid if obtained from the mean squares of lines x tasters mating design while, the dominance genetic variances would be obtained with more validity from the diallel crosses mating design for most studied traits. | ||||
| Keywords | ||||
| Maize; General combining ability; Specific combining ability; Heterosis; hybrid and homogeneity test | ||||
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