[Compensation effect of cotton growth and development after soil salt content reduction at bud stage].

To elucidate the dynamic characteristics of cotton growth and development after soil salt content reduction (SD) at bud stage and its effect on yield formation, a pot experiment was conducted in which soil salt content was declined from 5 per thousand level to 2 per thousand level at cotton bud stage. The results showed that the plant height, biomass, total fruit branch and fruit node number, boll number, boll mass of cotton plants increased after soil salt content reduction at bud stage. The distribution proportions of biomass in root and boll decreased after soil salt content reduction, however, the distribution proportions of biomass in leaf, main stem and fruit branch were on the rise. The growth rate of cotton plant increased after soil salt content reduction. Plant dry matter accumulation rate of SD cotton exceeded CK cotton at 22 days after soil salt content reduction. The response of different organs of cotton plant were different to soil salt content reduction, the plant height was the earliest, followed by the fruit branch and fruit node formation, and the bud and boll were the latest, which indicated that the compensation effect of cotton growth and development after soil salt content reduction at bud stage firstly appeared on the formation and growth of new leaf, fruit branch and fruit node, and on this basis, gradually brought out yield compensation.

[Tagging and mapping of QTLs controlling lint yield and yield components in upland cotton (Gossypium hirsutum L.) using SSR and RAPD markers].

Using interval mapping and marker simple regression methods, the QTLs of yield and its components in (Simian 3 x TM-1) F2 and F2:3, were tagged and Mapped with 39 SSR and 10 RAPD markers having polymorphism between parents screened from 301 pair SSR primers and 1040 RAPD primers. Simian 3 is being grown extensively in Yangtze River cotton-growing valley characterized as high productivity with more bolls and higher lint percent, whereas TM-1, Genetic standard in Upland cotton with more heavy boll weight. In the present report, two QTLs controlling boll size with 18.2% and 21.0% phenotype variance explained in F2:3 generation, one QTL controlling lint percent with 24.9% phenotype variance explained in F2 generation and 5.9% in F2:3 generation and one QTL controlling 100-seed weight with 15.6% phenotype variance explained in F2:3 generation were mapped in Chromosome 9. Additionally, another QTL responsible for 100-seed weight was identified and mapped at the same position in Chromosome 9 in F2:3 generation. It is worth for further to be studied whether it is one QTL for pleiotrophism or two closely linked QTLs. The molecular markers mapped and tagged closely with main QTLs of yield traits in this paper can be used for MAS in cotton high-yield breeding program.