低温胁迫对北疆棉花出苗的影响及适宜播种期的研究

【目的】为了解决新疆北疆地区棉花播种出苗期低温冷害问题,【方法】利用人工气候室,对种子低温胁迫设计不同温度进行播种出苗试验,并结合近20年农业气象观测资料,研究播种至出苗的适宜播种温度指标、积温指标、确定棉花适宜播种期。【结果】试验结果表明：棉花种子的萌芽率、萌芽天数、萌芽长度、萌芽鲜重及出苗率等各项参数随温度呈非线性有规律变化。棉花种子低温胁迫时间越长出苗越滞后,所需的积温较多。北疆地区棉花主栽品种播种出苗下限温度为12℃,需要活动积温在160℃.d以上,≥12℃有效积温在55℃.d以上。【结论】通过人工气候室试验结合大田实际监测研究,新疆北疆地区稳定通过12℃应作为棉花主栽品种播种的初始期；播种期确定在4月下旬,出苗期可免受春季低温冷害的威胁。

Seedling Emergence of Cotton in Northern Xinjiang: Low Temperature Stress Effects and Suitable Seeding Time

To understand the low temperature chilling damage at sowing and seedling emergence stage of cotton in northern Xinjiang, with the artificial climate chamber, we designed different low temperature stresses for sowing and seedling emergence test, and studied the suitable sowing temperature index, accumulated temperature index from sowing to seedling emergence period and suitable sowing time of cotton, combined with the agricultural meteorological observation data during 1991-2017. The results showed that: the parameters, such as germination rate, germination days, length of germination, fresh weight of germination and seedling emergence rate, had non-linear and regular changes with temperature; the longer the time of low temperature stress, the later the seedling emergence, the more the accumulated temperature needed; the minimum temperature for seedling emergence of main cotton varieties in northern Xinjiang was 12℃, and the required accumulated temperature was above 160℃ · d, the effective accumulated temperature of 12℃ or higher was above 55℃·d. Through artificial climate chamber test in combination with the practical monitoring research in field, the temperature steadily passing 12℃ in northern Xinjiang should be used as the initial period for planting main cotton varieties; the seeding time should be in late April, thus the seedling stage can be free from the spring cold damage.