Abstract:

【Objective】 The perennial cultivation of annual cotton is very important for maintaining genic male sterile lines, producing hybrid seeds, fixing heterosis and preserving special germ plasm. The changeable law of the yield and quality characters of perennial cultivation of annual upland cotton was researched to supply a theoretical evidence of perennial cultivation. 【Method】 Random block design and orthogonal arrays were set up to investigate the yield and quality characters of triennial and biennial cultivation of annual upland cotton among 4 varieties of upland cotton, with annual cultivation as contrast,in Nanning, Guangxi from 2005 to 2007.【Result】 The yield of perennial cultivation was very significantly higher than that of annual cotton, the average lint yield of 4 varieties of the triennial and biennial cotton were 1 391.75 and 1 491.37 kg?hm-2, increased by 39.98% and 50.00% compared with that of the annual cotton. The lint yield of the triennial and biennial cotton of the high yield variety Zhong 928 F1 reached 1 781.67 and 1 882.94 kg?hm-2, increased by 53.95% and 62.71% compared with that of the annual cotton. There were no significant effects of the perennial ages on the yield. The fibre quality of the perennial cultivation had no obvious difference with that of the annual cotton. There were no significant effects of the perennial ages on the 2.5% span length,strength, micronaire, and metric number. 【Conlusion】 The result indicates that the yield of perennial cultivating was very significantly higher than that of annual cotton,the fibre quality of the perennial cultivation had no obvious difference with that of the annual cotton,the perennial cultivation may be directly used for production with finer prospect. The insect-resistant hybrid cotton cultivars with high yield should be selected for perennial cultivation.

Key words: perennial upland cotton, yield and quality characters, changeable law