عنوان مقاله [English]
Background and objectives: The increase in global temperature predicted by several climate models has a direct impact on plant growth, yield, and cotton quality. This type of temperature change in agriculture can be produced by planting crops at different dates and growing crops under different temperature and humidity conditions. The objective of this research is to model the evolution of phenology in commercial cotton varieties using meteorological parameters.
Materials and methods: To determine the required GDDs of commercial cotton varieties under different planting dates, field experiments were conducted in 2018 in two regions, Hashem-Abad (Gorgan) and Karkandeh (Kordkoy). To estimate the effects of planting date on phenology, field experiments were conducted using a split-plot design with 6 planting dates (15 days apart) as the main plot and 3 cultivars (Golestan, Latif and Sajedi) as subplots with 3 replicates. Data analysis was performed using SAS software and Excel software was used to prepare the graphs.
Results: The results showed that the effect of planting date on days required from planting to boll opening was significant at p = 1% in both Karkandeh and Hashem-Abad. Thus, with a delay in planting date, the number of planting days to emergence increased from 7 and 9.1 to 4.6 and 3.1 days in both Karkandeh and Hashemabad, respectively; to the budding stage from 52 and 46 to 29.2 and 23.2 days, respectively; to flowering from 63.3 and 57.9 to 41.9 and 33.3 days, respectively; to flowering from 75 and 63.8 to 58.The results of yield comparison showed that the highest yield of total cotton (4015 kg ha-1) was associated with the second planting date among the employees and in Hashemabad the highest yield of total cotton (4122 kg ha-1) was obtained with the third planting date.
Conclusion: The results of this study showed that the GDD required for cotton cultivation was significantly different among the different planting dates.