Studies On Heterosis Utilisation Between Upland Cotton And Island Cotton

This research used the light and heat resources of the South China cotton region to study the growth development mechanisms, yield, quality, and heterosis performance of upland cotton, island cotton, and hybrids between upland cotton and island cotton. It also compared the main characteristics of annual and biennial island cotton and hybrids between island cotton and island cotton, providing a reference for promoting island cotton and the hybrids between upland cotton and island cotton and their perennial cultivation in the South China cotton region.The research used 7 F₂ hybrids between upland cotton and island cotton, 2 upland cottons, 1 island cotton, as well as 1 biennial island cotton and 1 biennial hybrid F₁ of island cotton and island cotton, for a total of 12 materials. Compared with the character performance of 7 hybrid F₁ of island cotton and island cotton, it studied each character heterosis performance of hybrid a7 (77/island cotton) and compared the main characteristics between annual and biennial island cotton and hybrids between upland cotton and island cotton. These were the results:1. Among the 7 hybrids between upland cotton and island cotton, the hybrid combinations whose yields were better were 77/island cotton, A4/island cotton, and A5/island cotton. The textile fiber quality was better for A5/island cotton, A3/island cotton, and A2/island cotton.2. Heterosis performance of hybrids between upland cotton and island cotton: the growth speed per day, plant height, stem diameter, seed index, number of bolls per plant, seed cotton yield, lint cotton yield, modal length, quartile length, and uniformity had heterosis over the better parent. The respective rates were 11.39%, 12.00%, 14.24%, 11.54%, 93.98%, 97.17%, 66.34%, 10.70%, 10.09%, and 4.43%. In addition, boll weight, rate of sterile seeds, and breaking strength had heterosis over a respective mean over the parents of 22.88%, 25.10%, and 8.92%. Lint percentage, short fabric rate, cardinal number, metric count, and micronaire value displayed negative heterosis over the mean of the parents of -10.99%, - 62.69%, - 9.76%, -1.37%, and - 3.75%, respectively.3. Comparing the main characteristics of annual and biennial island cotton and hybrids between upland cotton and island cotton: the biennial island cotton had superiority in all yield characteristics except stem diameter and seed index, the seed cotton yield of which was 64.97% higher than the annual. The biennial hybrid of island cotton and island cotton had superiority in all main yield characteristics, while the lint percentage was significantly improved and the rate of sterile seeds significantly decreased. In addition, the Lint cotton yield was 94.11% higher than the annual. The annual island cotton lives the island cotton with two years, and there was no remarkable difference in textile fiber quality between annuals and biennials.As a consequence, 77/island cotton, A4/island cotton, and A5/island cotton are the 3 best hybrids, because the main yield & quality characteristics of the hybrids between upland cotton and island cotton had heterosis over the mean of the parents-and even over the better parent. The Lint cotton yield of biennial cotton was significantly improved and the quality was uniform, which explains why island cotton and hybrids between upland cotton and island cotton and perennial cultivation have good potential in this region.The management and working life of perennial cotton were two important problems which should be researched more.