عنوان مقاله [English]
Background and objectives: Flowering time is one of the key developmental stages in determining the adaptation and grain yield of wheat and in this regard, management of planting date and cultivar, which leads to more matching the important developmental stage of flowering with the optimal flowering period, is very important in determining wheat grain yield. The aim of this study was to evaluate the phenological adaptation and its effect on grain yield of wheat cultivars with different seed densities under dryland pending cultivation conditions (conditions that plant emergence occurs after the end of winter cold; entezari in persion) in cold regions.
Materials and methods: In order to evaluate the compatibility and determine the grain yield potential of dryland wheat cultivars in the pending conditions of cold regions, an experiment was carried out during two years of 2019-2020 in two dryland research stations of Shirvan and Sisab in North Khorasan province in the form of split plots in a completely randomized block design with three replications. In this experiment, dryland spring, facultative and winter wheat cultivars were evaluated as main plot and five densities of 150, 200, 250, 300 and 350 seeds/m2 were evaluated as sub-plots.
Results: Evaluation of developmental stages showed that cultivation in this condition, in first year none of wheat cultivars pollinated in optimal flowering period but spring cultivars passed the critical flowering stage earlier and closer to the optimal flowering period than winter cultivars in both years. The results showed that there in first year, yield difference of cultivars was significant and winter wheat cultivar of Sadra with 1524 kg/ha had the lowest grain yield and grain yield of other cultivars varied in the range of 1880-2110 kg/ha but their difference was not significant. In second year, the difference in grain yield of cultivars was not significant but percentage of grain sieving as a grain quality index in this year, showed a significant difference and, in this regard, spring cultivars showed superiority over winter cultivars so that the highest rate of this trait was observed in spring Aseman cultivar (86%) and the lowest rate was observed in Baran winter cultivar (52%). Grain yield was not affected by seed density but at low seed densities (150 and 200 seeds/m2) coverage of the soil happened with delay.
Conclusion: Based on the results, spring wheat cultivars of Aseman and Karim are recommended for pending cultivation in cold area, especially cold and low rainfall area, however, research is needed to achieve more compatible and more productive cultivars for these conditions. Desirable seed density of wheat cultivars for sowing in dryland pending conditions will be 250-300 seeds/m2.