Abstract:
【Objective】 To make the correlation analysis between the angle of fruit branches of upland cotton resources and the agronomic traits in the hope of finding the range of fruit branches the agricultural characteristics of the machine, and select the cotton varieties suitable for the machineangle suitable for machine picking with high yield and selecting the cotton varieties suitable for the machine.
【Methods】 Descriptive statistics, correlation, clustering and principal component analysis were carried out on fruit branch angle and agronomic traits of 300 upland cotton germplasm resources.
【Results】 The variation coefficient of the other 7 traits was greater than 10% except for the number of fruit branches, coat fraction, weight of single boll and angle of fruit branches, and the variation coefficient of the number of boll per plant was the largest, which was 25.28%. There was significant positive correlation between fruit branch angle and yield characters such as boll weight, lint quality and effective fruit branch number. When the Euclidean distance was 4, 300 pieces of upland cotton could be divided into 5 groups according to the size of the angle between the fruit branches, which are 47.5°-50.1°, 50.9°-55.5°, 55.7°-58.5°, 58.6°-62.8°, 63.2°-66.5°. Group I had the smallest fruit branch angle, short plants and low yield potential. The fruit branch angle size and the plant height of the second and third group were suitable, the plants were compact, the plant type was mostly tower type, barrel type, easy to pick and the yield was higher. As for class IV and V, the branch angle their plant type was mostly tower type and inverted tower type, and their yields were high with high yield potential. A total of 4 principal components were extracted from the principal component analysis, and the cumulative contribution rate was 74.87%, which explained most of the information of agronomic traits of 300 upland cotton resources. The principal component factors were respectively the height of the beginning of fruit branch, the number of effective fruit branch and the weight of single boll.
【Conclusion】 There is a significant positive correlation between fruit branch angle and yield traits in upland cotton. When the branch branch angle is 47.5°-65.5°, the larger the branch angle is, the higher the yield traits are. When the angle range of fruit branches is 50.9°-58.5°, the cotton yield is higher and meets the requirements of machine-picked cotton. The comprehensive score evaluation of cotton varieties in this range is carried out, and 10 cotton varieties suitable for machine-picked cotton varieties are selected as excellent breeding materials.