海岛棉品系对脱叶剂喷施时间及频次的响应研究

为明确脱叶剂喷施时间、频次对不同海岛棉品系脱叶、吐絮、产量性状及纤维品质的影响，以品系ZX102和ZX113为试验材料，采用三因素完全随机试验，设置3个喷施时间，2种喷施频次，分析不同海岛棉品系对不同处理的响应。结果表明：使用脱叶剂能明显提高脱叶率，吐絮率为40%和50%下两品系药后15 d左右时脱叶率已达90%且显著高于清水对照(P<0.05)；吐絮率40%和50%下使用脱叶剂使两品系马克隆值、上半部平均长度、比强度有所降低，表现为：CK>T₂>T₁，其中40%时T₁处理的马克隆值显著低于CK(P<0.05)，不同处理下两品系铃重和籽指表现为：CK>T₂>T₁，其中40%时T₁处理的铃重显著低于CK(P<0.05)。在海岛棉机械采收实践中，为保证产量和纤维品质，当田间吐絮率50%时可采用T₂喷施方式来实现。

The Response of Sea-island Cotton Strains to the Spraying Time and Frequency of Defoliants

In order to clarify the effects of spraying time and frequency of defoliants on leaf abscission, boll opening, yield traits and fiber quality of different sea-island cotton strains, ZX102 and ZX113 were used as test materials and 3 spraying times and 2 spraying frequencies were set. Three-factor completely randomized experiments were used to analyze the responses of different sea-island cotton strains to different treatments. The result showed that the use of defoliants significantly improved the defoliation rate, and the defoliation rate of the two strains at 40% and 50% boll opening rate reached 90% about 15 days after using defoliants, and they were significantly higher than that of the water control (P<0.05). The use of defoliants at 40% and 50% boll opening rate reduced the macron value, fibre length and fibre strength of the two strains, which were manifested as CK>T₂>T₁; at 40% boll opening rate, the macron value under T₁ treatment was significantly lower than that under CK (P<0.05). The boll weight and seed value of the two strains under different treatments were CK>T₂>T₁, and the boll weight at 40% boll opening rate under T₁ treatment was significantly lower than that under CK (P<0.05). In order to ensure the yield and fiber quality, T₂ spraying can be used at 50% boll opening rate for mechanical harvesting of sea-island cotton.