Effect Of Plant And Row Spacing On Canopy Structure And Boll Setting Of Machine-picked Cotton

【Object】The objective of the experiment was to study the effect of different plant and row spacing on the canopy structure and boll setting of machine-picked cotton, ascertain the physiological basis of high yield and fine fiber quality system and explore the suitable plant and row spacing and cultivation techniques of optimize canopy structure, boll setting and improve the fiber quality of raw cotton, which were important theoretical basis to establish and improve Xinjiang machine-picked cotton comprehensive cultivation technique.【Methods】The experiment was carried out in Regimental Farm 127, Agriculture Division 7 of Xinjiang Construction Groups. Under the field conditions, hybrid cotton Lumianyan 24 which was widely planted in Agriculture Division 7 of Xinjiang Construction Groups and conventional cotton Xinluzao 60 were used as materials. Three kinds of plant model:(1)a film of three lines(76cm+76cm+76cm), the average plant space was 12cm;(2)a film of six lines(66cm+10cm), the average row space was 38 cm and the average plant space was 12cm;(3)a film of three lines with double plants(76cm+76cm+76cm), the average plant space was 12 cm. The main agronomic characters(plant height, leaf age, the first fruit branch node and the number of fruit branches), chlorophyll relative content(SPAD value), the processing characteristics of photosynthate accumulation and distribution, canopy structure index(LAI、DIFN and LIR), spatial-temporal distribution of bolls, defoliation rate and boll opening rate, boll stage and fiber quality, yield and yield components were investigated.【Results】(1) Effect of Plant and Row Spacing on Agronomic Characters and Yield of Machine-picked Cotton. The plant height, daily increase of plant height, leaf age and length of first fruit branch node of a film of three lines were higher than that of a film of six lines and a film of three lines with double plants. The defoliation rate of a film of three lines was higher than that of a film of six lines. There were no significant differences of total bolls in the three treatments of each cultivar. The boll weight of a film of three lines was higher than the other two treatments. The yield in a film of three lines of hybrid cotton Lumianyan 24 and a film of six lines of conventional cotton Xinluzao 60 were highest of each cultivar in harvest.(2) Effect of Plant and Row Spacing on Canopy Structure and Matter Production of Machine-picked Cotton. The LAI and LIR of a film of three lines of hybrid cotton Lumianyan 24 and a film of six lines of conventional cotton Xinluzao 60 were highest of each cultivar in the late growth stage. The DIFN of a film of three lines of hybrid cotton Lumianyan 24 was lower than the other two treatments in the late growth stage. The SPAD of a film of three lines of hybrid cotton Lumianyan 24 was highest of the three treatments. The amount of total photosynthate accumulation of a film of three lines of hybrid cotton Lumianyan 24 and a film of six lines of conventional cotton Xinluzao 60 were the highest in the three treatments of each cultivar in the late growth stage. The distribution rates of total photosynthate accumulation in buds and bolls a film of three lines was higher than the other two treatments of hybrid cotton Lumianyan 24 and the distribution rates of total photosynthate accumulation in buds and bolls a film of six lines was highest in the three treatments of conventional cotton Xinluzao 60.(3) Effect of Plant and Row Spacing on Boll Setting and Fiber Quality of Machine-picked Cotton. The number of early summer bolls and summer bolls per plant were highest in the three treatments of each cultivar. The boll setting percentage on more than 7th fruit branches and more than 2th fruit nodes were higher than the other two treatments. The boll stage of 3th fruit nodes were longer than that of 1-2th fruit nodes and the boll stage of upper fruit branches was longer than that of bottom branches. The boll stage of a film of three lines with double plants were shortest in the three treatments of each cultivar. The boll stage and boll opening rate of hybrid cotton Lumianyan 24 were shorter than conventional cotton Xinluzao 60 in the three treatments. The micronaire and boll opening rate of hybrid cotton Lumianyan 24 were higher than conventional cotton.【Conclusion】There were higher plant height, the length of first fruit branches, defoliation rate and boll opening rate of a film of three lines of hybrid cotton Lumianyan 24, and the main agronomic characters of a film of three lines were meet all the requirements of machine-picked cotton. A film of three lines of hybrid cotton Lumianyan 24 had higher group photosynthesis efficiency with higher LAI and LIR, and the highest photosynthate accumulation in the late growth stage. The boll setting percentage of more than 7th fruit branches and more than 2th fruit nodes of fruit branches of a film of three lines of hybrid cotton Lumianyan 24 were higher and it had the highest single boll weight, fine fiber quality and the highest yield. The highest bolls number and boll weight were the base of highest yield of a film of six lines of conventional cotton Xinluzao 60.