Sürdürülebilir Kalkınma Amaçları
Yazarlar
Yayınlar
- MakaleYalnız künye2010Responses of some wheat genotypes and their F2 progenies to salinity and heat stress
Yildirim, Mehmet; Bahar, Bilge
Both heat and salinity cause yield decrease in wheat. Grain yield in wheat has increased as a result of breeding efforts for different stress conditions. However, there are still substantial opportunities to improve grain yield by using conventional breeding under stress conditions, like heat and salt stress. The objective of this study was to investigate heat and salt effects on yield and some agronomic traits of four wheat genotypes and their six half F2 diallel cross progenies grown in pots. Significant differences were found among the genotypes for grain yield under both heat stress and non-stress condition. There was a mean reduction in yield of 12.6% due to salt stress. The reduction in biomass was higher than grain yield under salt stress while it was lower at heat stress. Grain yield was positively correlated with spike weight, harvest index, grain numbers per plant and biological yield under non stress (NS), heat stress (HS) and salt stress (SS) conditions. Cultivars Seri 82 and Chil's had high yield among parents under both NS and SS. Chil's and its hybrids showed low reduction in yield due to SS; thus, exhibiting salt tolerance. Also, Chil's was found to be good combiner with high General Combining Ability (GCA) effects for grain yield under SS conditions. 84 CZT04 was the most susceptible cultivar under SS. Significant GCA effects of Genç 99 and 84CZT04 provided positive contribution to grain yield under HS. It was impossible to select both heat and salt tolerant genotype with high yield capacity from the used genotypes. However, heat or salt tolerant genotypes can be improved by selection breeding due to genetic variation among genotypes.
- MakaleAçık Erişim2009Membrane thermal stability at different developmental stages of spring wheat genotypes and their diallel cross populations; [Yazlık buǧday genotipleri ve diallel melez populasyonlarının farklı gelisme dönemlerinde yüksek sıcaklık membran kararlılıǧı]
Yildirim, Mehmet; Bahar, Bilge; Koç, Müjde; Barutçular, Celalettin
Membrane thermal stability (MTS) can be a significant selection criterion for heat stress tolerance. MTS is determined by measuring of electirical conductivity of aquause phase in which leaf tissue exposure to high temperature. This research was conducted to investigate the membrane stability assay measured by two different methods, namely MTS and relative injury (RI). The second objective of this experiment was to determine the effects of different growth stages of four spring wheat parents and their six half F2 diallel cross progenies grown in the field on membrane stability. Measurements were taken at different growth stages (seedling, stem elongation and early milk). The MTS and RI assays gave similar results at the three different growth stages. However, growth stages significantly affected the MTS and RI values of genotypes. Membrane stability parameters of genotypes decreased during the later developmental stages. Specific combining ability effects were superior to general combining ability effect for all measurements, indicating that membrane thermal stability was mediated mainly by non-additive gene actions. Membrane stability of flag leaf at the early milk stage was significantly correlated with grain yield. The parent of Genç 99 and 84ÇZT04 had low yield potential, whereas Chil's and Seri 82 had high yield potential. Grain yield, spike yield and kernel weight of F2 population were found higher than their parents. These results suggest that genetic variation among genotypes for membrane stability can be utilized in wheat breeding in heat-stressed environments.