Identification of High Yield Diagnostic Indexes and Study on the Growth Regularity of Yield Formation in Chemical Top-Capping Cotton

【Objective】 This project aims to study the growth and development regularity and leaf age index corresponding to yield formation of cotton with chemical top-capping in northern Xinjiang and establish high-yield diagnostic indicators and explore its growth regularity. 【Methods】 The experiment was carried out in Liuhudi Town in 2016. Three cotton fields with high yield, middle yield and low yield were selected to explore the changing regularity of cotton growth process and agronomic indicators in different fields, and analyze and establish the diagnostic index table. 【Result】 There were differences in the performance of plant types in different growth stages of cotton fields, mainly in the time of leaf emergence, stem diameter, fruit bud, flowering and boll opening. After the above indicators were analyzed and quantified, the leaf age high-yield diagnostic index table of the "leaf age-relative plant height method" and "leaf age-relative stem method" of chemical detopping high-yield cotton field was established. The results showed that the number of main stem leaves in chemically capped high-yield cotton fields was 17 and the plant height was 75-80 cm. The growth of plant height after chemical detopping was less than 10 cm. The bud and flowering rate of the first fruit node of each fruit branch was 3 days/set, the boll opening rate was 2.12 days/set, the best bud period to full bloom period was 22 days, and the flowering period to boll opening period was 57.5 days. 【Conclusion】 In order to keep the chemical detopping cotton fields at a relatively high level, it is necessary to control the shape of plant, the speed of leaf emergence and the growth of cotton reasonably in different growth stages.