Abstract:

【Objective】 To explore photosynthesis characteristics, summarize the principle of yield formation, and propose yield components and photosynthetic physiological indexes, experiments were conducted with super-high-yield cotton in field. It was of great significance to excavate yield potential and construct super-high-yield cultivation technique system. 【Method】 One hybrid cotton cultivar Biaoza A1 and four traditional cultivars including Xinluzao 13, Xinluzao 26, Wanshi 217 and Wanshi 315 were selected as the experimental materials. Leaf area index, chlorophyll SPAD value, photosynthetic rate, photosynthate accumulation and distribution were measured at different growth stages. 【Result】 Compared to high yield traditional cultivar, super-high-yield hybrid cultivar (lint 3 500 kg?hm-2) had higher leaf area index, chlorophyll SPAD value and photosynthetic rate, all of which had longer duration during growth stage. Furthermore, the ratio of canopy respiration rate to total canopy apparent photosynthesis rate which maintained at a low level at the middle and late growth stage, was significantly lower than that of high yield traditional cultivar especially at early boll opening stage. Biaoza A1 had longer and earlier linear increase stage of vegetative organs photosynthate accumulation, which led to greater photosynthate accumulation. However, the linear increase stage of reproductive organs and total photosynthate accumulation and the peak of accumulation appeared comparatively later than those of high yield traditional cultivar. 【Conclusion】 The indexes of yield components and photosynthetic physiology of super-high-yield Biaoza A1 (lint 3 500 kg?hm-2) were proposed, i.e., total number of bolls＞150×104?hm-2, boll weight ＞5.5 g, lint percentage ＞44%; leaf area index at early full bolling stage 4.9-5.2, at early boll opening stage above 3.3; chlorophyll SPAD value at full bolling stage 65.4-66.5, at early boll opening stage above 64.8; net photosynthetic rate at flowering and boll forming stage 32.2-36.5 μmol?m-2?s-1, at early boll opening stage above 22.2 μmol?m-2?s-1; canopy apparent photosynthesis rate at early full bolling stage approximately 43.4 μmol?m-2?s-1, at early boll opening stage above 16.3 μmol?m-2?s-1; total photosynthate accumulation approximately 26 345.4 kg?hm-2, economic coefficient no less than 31%.

Key words: cotton, Biaoza A1, super-high-yield, photosynthesis characteristics, Xinjiang