Abstract: The genetic improvement and photosynthate characteristic of different genotypes of cottons were studied in 2001 and 2003. In this report,the fifteen cotton breeds were divided into three genotypes. The first was DGC(double gene cotton,transgenic CrylAc plus CpTI cotton),including SGK321,Zhongmian-41, Zhong-mian-45,ZGK193,ZGK204. The second was SGC(single gene cotton, transgenic Bt cotton),including Jinmian-26, Jinmian-31, J inmian-33,Zhongmian-32,Zhongmian-35. The last was common cotton (CC),including Jinmian-25, Jinmian-12,Zhongmian-35,Zhongmian-12,Zhongmian-23.The results showed that there were no great differences about max of photosynthesis (Pnmax) among three genotypes cottons. All of these Pnmax appeared in budding and flowering periods. The correlation of photosynthesis and yield of cotton was not visible. The main action of photosynthesis for yield of cotton was not directly. It affected biomass of cotton to yield. The distributive rate of accumulation on source and sink organs were different in three genotypes of cotton. The effective utilization ratio (EUR) of photosynthnate accumulated after anthesis(PAAA) was different in three genotypes of cotton, and CC was the biggest and SGC smallest. The influence to yield by photosynthnate accumulated before anthesis (PABA) was different in three genotypes of cotton, which was SGC>DGC>CC. The decreasing of biomass of SGC and DGC were mainly due to PABA decrease. The output rates of PAAA of SGC and DGC were higher than CC. But more PAAA was stored in the boll shell,which had important effect on increasing boll weight of SGC and DGC. It was suggested that we should pay attention to PABA and boll weight in SGC and DGC breeding selection.

Key words: Cotton, External gene, Photosynthetic, Genetic improvement

CLC Number: 

• S562.01