This study was carried out in the two growing seasons of 2008 and 2009. Five experiments were conducted in each season in the Experimental Agricultural Farm, Faculty of Agriculture, Assiut University. Each experiment represented one planting date. Through each experiment two variables were designed in split-plot design in which time of thinning was allotted in the main plots, whereas splitting NPK was in the sub-plots. The obtained results could be summarized as follows: 1-Total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll in gram and Seed cotton yield of Kentar/fed were decreased significantly as planting date was delayed, On the contrary node number of the first sympodium was lowered. 2-The data revealed that thinning before the second irrigation favoured Plant height, total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield of March plantings, whereas the reverse was true with regard to the late plantings, i.e., thinning before first irrigation., On the contrary of that node number of the first sympodium was lowered in march plantings. 3-The data revealed that splitting fertilization increased significantly total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield. On the contrary of that node number of the first sympodium was lowered.

This study was carried out in the two growing seasons of 2008 and 2009. Five experiments were conducted in each season in the Experimental Agricultural Farm, Faculty of Agriculture, Assiut University. Each experiment represented one planting date. Through each experiment two variables were designed in split-plot design in which time of thinning was allotted in the main plots, whereas splitting NPK was in the sub-plots. The obtained results could be summarized as follows: 1-Total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll in gram and Seed cotton yield of Kentar/fed were decreased significantly as planting date was delayed, On the contrary node number of the first sympodium was lowered. 2-The data revealed that thinning before the second irrigation favoured Plant height, total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield of March plantings, whereas the reverse was true with regard to the late plantings, i.e., thinning before first irrigation., On the contrary of that node number of the first sympodium was lowered in march plantings. 3-The data revealed that splitting fertilization increased significantly total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield. On the contrary of that node number of the first sympodium was lowered.

This study was carried out in the two growing seasons of 2008 and 2009. Five experiments were conducted in each season in the Experimental Agricultural Farm, Faculty of Agriculture, Assiut University. Each experiment represented one planting date. Through each experiment two variables were designed in split-plot design in which time of thinning was allotted in the main plots, whereas splitting NPK was in the sub-plots. The obtained results could be summarized as follows: 1-Total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll in gram and Seed cotton yield of Kentar/fed were decreased significantly as planting date was delayed, On the contrary node number of the first sympodium was lowered. 2-The data revealed that thinning before the second irrigation favoured Plant height, total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield of March plantings, whereas the reverse was true with regard to the late plantings, i.e., thinning before first irrigation., On the contrary of that node number of the first sympodium was lowered in march plantings. 3-The data revealed that splitting fertilization increased significantly total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield. On the contrary of that node number of the first sympodium was lowered.

This study was carried out in the two growing seasons of 2008 and 2009. Five experiments were conducted in each season in the Experimental Agricultural Farm, Faculty of Agriculture, Assiut University. Each experiment represented one planting date. Through each experiment two variables were designed in split-plot design in which time of thinning was allotted in the main plots, whereas splitting NPK was in the sub-plots. The obtained results could be summarized as follows: 1-Total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll in gram and Seed cotton yield of Kentar/fed were decreased significantly as planting date was delayed, On the contrary node number of the first sympodium was lowered. 2-The data revealed that thinning before the second irrigation favoured Plant height, total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield of March plantings, whereas the reverse was true with regard to the late plantings, i.e., thinning before first irrigation., On the contrary of that node number of the first sympodium was lowered in march plantings. 3-The data revealed that splitting fertilization increased significantly total soluble carbohydrates, number of open bolls per plant, weight of seed cotton per boll and Seed cotton yield. On the contrary of that node number of the first sympodium was lowered.

NULL

Drought is an important abiotic stress causing the major crop losses worldwide. Identification of genomic regions associated with drought-related traits is essential for improving drought tolerance in barley. Association mapping was implemented to investigate the associations between 76 SSR markers and six drought-related traits on a set of 107 barley accessions evaluated under well-watered and drought-stressed conditions. Highly significant differences between well-watered and drought-stressed conditions were observed in all measured traits. A high level of polymorphism with SSR markers was observed. A total of 36 significant marker–trait associations for drought-related traits were detected. A high extent of significant LD (> 61%) was observed between markers on different chromosomes, suggesting epistatic interaction. Several molecular markers are significantly associated with more than one phenotypic trait, suggesting the possible presence of pleiotropic or indirect effects. The phenotypic variation, explained by individual marker–trait associations, ranged from 6.33% to 35.78%.

Drought negatively affects plant development, growth, yield, and ultimately production of crop species. Association analysis of yield and yield-contributing traits was conducted for a barley germplasm collection consisting 07 wild (Hordeum spontaneum L.) genotypes, originating from 12 countries using 76 SSR markers. Phenotypic evaluations were performed for days to heading, plant height, number of tillers/plant, spike length, thousand kernel weight, single plant yield under well-watered and drought-stress conditions. Highly significant differences between well-watered and drought-stress conditions were observed in all measured traits. Association analysis revealed a total of 83 significant marker–trait associations for all six measured traits. The results revealed that several chromosomal regions significantly influence more than one trait, suggesting a possible existence of pleiotropic or indirect effects. The phenotypic variation explained by individual marker–trait associations ranged from 5.08 to 27.84%. The results demonstrat-ed that wild barley is a valuable source for improving yield and yield-contributing traits for drought tolerance. Our data provide a tool kit for the potential application of marker-assisted selection for drought tolerance in barley.

This study demonstrates for the first time that resistance to different root lesion nematodes ( P. neglectus and P. penetrans ) is controlled by a common QTL. A major resistance QTL ( Rlnnp6H ) has been mapped to chromosome 6H using two independent barley populations. Root lesion nematodes (Pratylenchus spp.) are important pests in cereal production worldwide. We selected two doubled haploid populations of barley (Igri × Franka and Uschi × HHOR 3073) and infected them with Pratylenchus penetrans and Pratylenchus neglectus. Nematode multiplication rates were measured 7 or 10 weeks after infection. In both populations, continuous phenotypic variations for nematode multiplication rates were detected indicating a quantitative inheritance of resistance. In the Igri × Franka population, four P. penetrans resistance QTLs were mapped with 857 molecular markers on four linkage groups (2H, 5H, 6H and 7H). In the Uschi × HHOR 3073 population, eleven resistance QTLs (P. penetrans and P. neglectus) were mapped with 646 molecular markers on linkage groups 1H, 3H, 4H, 5H, 6H and 7H. A major resistance QTL named Rlnnp6H (LOD score 6.42-11.19) with a large phenotypic effect (27.5-36.6 %) for both pests was mapped in both populations to chromosome 6H. Another resistance QTL for both pests was mapped on linkage group 5H (Igri × Franka population). These data provide first evidence for common resistance mechanisms against different root lesion nematode species. The molecular markers are a powerful tool for the selection of resistant barley lines among segregating populations because resistance tests are time consuming and laborious.

NULL

NULL