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为了明确棉花库源比(铃叶比)变化对红叶茎枯病发生的影响,揭示红叶茎枯病的病因,本研究开展了多项试验。试验结果显示,棉株的病害严重度与其铃叶比呈高度正相关。早熟品种开花期早,铃叶比高,病害发生重;盛蕾期以前的气温对棉花生长和红叶茎枯病发生的作用大于土壤水分的作用。与常温处理相比,提高棉花3叶期至盛蕾期的气温,可促进棉花的营养生长,减小库源比,其发病盛期延后约45 d,病情指数平均减少72.9%,棉花生物学产量平均提高123.8%;去蕾和推迟打顶均可降低棉花铃叶比,减轻病情,以去全蕾处理的作用最为明显;叶面喷施甲哌鎓可提高棉花铃叶比,利于病害发生。因此,铃叶比失调是红叶茎枯病的主要病因;开花期以前棉花代谢源(叶)的生长量决定着病害发生的时间和严重度。
In order to clarify the effect of cotton source-to-source ratio (boll ratio) on the occurrence of leaf blight and to reveal the etiology of stem blight, a number of experiments were carried out in this study. The test results showed that the disease severity of cotton plants was highly positively correlated with its bell-leaf ratio. Premature varieties flowering early, high ratio of bell leaves, disease occurred heavy; Shenglei pre-temperature on cotton growth and stem blight occurred more than the role of soil moisture. Compared with normal temperature treatment, the increase of cotton leaf temperature from 3 leaf stage to Shenglei stage could promote the vegetative growth of cotton and reduce the ratio of source to source. The peak period of the cotton was delayed by about 45 days and the average disease index decreased by 72.9% The yield was increased by 123.8% on average. The removal of buds and delayed topping all reduced the ratio of boll and boll, and alleviated the disease. The effect of boll-bud treatment was the most obvious. occur. Therefore, the imbalance of bell-leaf ratio is the main cause of leaf blight. The growth of cotton metabolism (leaf) before flowering determines the time and severity of disease occurrence.