SELECTION FOR EARLINESS, YIELD AND ITS COMPONENTS IN BREAD WHEAT | ||||
| Egyptian Journal of Plant Breeding | ||||
| Article 6, Volume 24, Issue 1, March 2020, Page 81-97 PDF (982.45 K) | ||||
| Document Type: Original research | ||||
| DOI: 10.12816/ejpb.2020.199308 | ||||
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| Abstract | ||||
| Developing new varieties with ideal genetic makeup to increase the yield potential under abiotic stresses is the first aim for wheat breeders to increase production area and narrow the gap between the local production and consumption. This investigation was carried out during three seasons: 2015/16, 2016/17 and 2017/18 at Toshka Agricultural Experiment Station of Desert Research Center, Aswan governorate, Egypt. Ten divergent parents of bread wheat were obtained (3, 4 and 3 genotypes from the Arab Center for the Studies of Arid Zones and Dry Lands (ACSAD), International Center of Agricultural Research in the Dry Areas (ICARDA) and International maize and wheat improvement center (CIMMYT), respectively)and their five crosses were used. Two cycles of Pedigree selection method were applied. First selection was practiced for the earliest lines in heading in F2 generation for sixty families and 300 plants from each cross and they were evaluated with their parents. The second selection cycle was done for greater number of grains per spike and 100-kernel weight in F3 plants. In F3 data were recorded on number of days to heading (days), number of days to maturity (days), plant height (cm), number of spikes/plant, number of spikelets/spike, 100-kernel weight (g), number of grains per spike and grain yield for each individual plant (g) for P1, P2 and F3 families by using the randomized block design. Highly significant differences were registered among F3 families for all traits under study. Mean performance for the five F3 families and parents showed that selected plants of the two crosses (4 and 5) were the earliest in days to heading (72.29 and 69.40 days) and days to maturity (111.37 and 106.91 days) and had the highest values for all traits under study that ranged from 6.97 g for 100 kernel weight to 124.99 cm for plant height in cross 5. While, the estimates of genetic variance within selected plants were higher than those among families for most studied traits in all studied crosses. Narrow sense heritability values were relatively medium to high for the five crosses ranged from 50.33% for maturity date in the cross 3 to 98.60% for heading date in the cross 2. These values were not much lower than the broad sense heritability in all crosses. The genetic variances among the F3 families exceeded corresponding environmental variances for most traits. The selected 33 plants from 4500 of F3 families considered to be superior segregants and could be promoted to the F4 generation to produce promising and improved pure lines and/or used as useful germplasm for future bread wheat breeding programs under stress conditions in Toshka. | ||||
| Keywords | ||||
| Bread wheat (Triticum aestivum); F3; Transgressive segregation; Yield and its components; Heritability; Genetic advance; Heat stress | ||||
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