大白菜热害发生规律及耐热性筛选方法的研究

Studies on Mode of High Temperature Injury and Screening Method for Heat Tolerant Chinese Cabbage

通过在不同高温条件下６个代表性品种的热害发生发展变化的研究，确定在３２℃恒温下对大白菜幼苗进行１０天的处理是耐热性选择的适宜选择压力。在此胁迫强度下，供试的两个耐热的台湾品种不出现热害症状；两个国内早熟品种出现轻度热害症状；两个晚熟品种热害症状严重。进一步的试验表明，根据苗期热害指数划分的耐热性等级与在田间高温条件下以结球性状为依据的耐热性和电导法测定的结果是一致的。苗期鉴定方法比结球期鉴定方法和电导法更容易控制选择压力，结果较精确，便于操作，能有效地提高选择效率。

Selection for heat tolerant Chinese cabbage (Brassica campestris ssp. L. pekinensis) genotypes is desirable. Experiments were performed to assess morphological effects of heat injury on heat-tolerant, intermediate and heat-sensitive Chinese cabbage cultivars. Keeping seedings under 32℃ for 10 days was determined to be optimal for screening of heat-tolerant breeding materials. Six cultivars under test showed significant difference in heat injury indices (HII) in the stress environment. The result was similar to those of the heed formation test and the electric conductivity test, while the method was more precise, controllable, operable and efficient. It was proposed that the method might be suitable for selecting heat-tolerant Chinese cabbage genotypes in breeding programs.