SELECTION FOR GRAIN YIELD PER PLANT UNDER HEAT STRESS IN BREAD WHEAT (Triticum aestivum L.) | ||||
| Assiut Journal of Agricultural Sciences | ||||
| Article 14, Volume 38, Issue 1, March 2007, Page 47-61 PDF (268.39 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ajas.2007.271101 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| M. K. Omara; N. A Mohamed; E. N. El-Sayed; M. A.El-Rawy | ||||
| Dept. of Genetics, Fac. of Agriculture, Assiut University, Assiut, Egypt. | ||||
| Abstract | ||||
| Divergent phenotypic selection for grain yield per plant under heat stress in wheat (Triticum aestivum L.) was performed in five F2 populations derived from crosses established between eight local landraces quite variable in heat susceptibility index under the heat stressed condition of a late sowing date. Selection was imposed on 200 F2 spaced plants for each of the five populations where the highest and the lowest five plants in grain yield were selected. Responses in grain yield per plant and the correlated response in a number of agronomic traits were measured in the F3 descending families of the selected F2 plants against the F3 bulks. Selection for higher grain yield per plant under heat stress produced significant positive responses in three populations derived from heat tolerant x heat susceptible crosses, with the responses ranging from 3.87 to 25.71% of population mean with an average of 11.59%. However, selection for lower grain yield per plant was ineffective in four of the five populations which substantiate the conclusion of other factors, possibly earliness supporting yield under heat stress. The heritability estimates of grain yield per plant under heat stress were rather low ranging from 0.03 to 0.19. Selection for higher grain yield per plant resulted in positive correlated responses in grain weight per spike which was significant in three populations and ranged from 0.93 to 8.56% with an average of 6.67% of population mean. In the low grain yield per plant direction, the grain weight per spike was significantly reduced in two populations only with an average reduction of 9.04% of the population mean. The heritability estimates were low ranging from 0.05 to 0.51. Positive and significant concurrent responses to selection for high grain yield were also obtained in 1000 grain weight in four of the five populations which ranged from 0.13 to 7.54% with an average of 4.47% of population mean. Meanwhile, significant reductions were obtained in 1000 grain weight in the five populations with selection for lower grain yield per plant which ranged from 3.74 to 18.31% with an average of 9.79% of population mean. The heritability estimates ranged from low (0.14) in one population to moderate to high in the other four (0.4 to 0.84). | ||||
| Keywords | ||||
| heat stress; Bread Wheat; grain yield | ||||
|
Statistics Article View: 61 PDF Download: 105 |
||||
