| Cotton is one of the most important crops around the world which can produce fiber on the seeds. Cotton production is forced by labor input. During recent years, as income-declining due to the price of labor force, the cotton production in China was decreasing continually. At present, the cotton production in China still was manual operation, and the cost of weed-control is one of main labor costs, which occupied one-third of total labor costs in cotton production. Glyphosate is a traditional broad-spectrum and systemic herbicide which is of the first place for weed-control particularly subserving perennial weeds. In present work, a glyphosate-resistant gene, EPSPS-G6, cloned in our university, was constructed as the target gene and transferred to upland cotton cultivar, ZMS 49, Agrobacterium-mediated transformation in vivo, and several transgenic cotton germplasms with EPSPS-G6 were obtained. In addition, the characters of glyphosate tolerance, agronomic traits, yield, and fiber quality of the transgenic cotton germplasms were investigated and surveyed, and the main research results were as follows:1. Constructing and transferring the target gene, EPSPS-G6, from plasmid pCAMBIA1300-EPSPS-G6 to plasmid pCAMBIA2301, a new recombination vector pCAMBIA2301-EPSPS-G6 was obtained. EPSPS-G6 in this vector could also serve as a plant selection marker gene.2. The method of Agrobacterium-mediated transformation in vivo developed in our lab was optimized by the transformation liquid with 50mg/L acetosyringone (AS), which could improve the transferred rate to 22.18%, about 2.28 times higher than that of control. Meanwhile, the transformation time was suggested to be 12:00～14:00 in blooming day, by which the positive rate was increased to 22.18%, higher than that in 13:00～15:00 and in 8:00-10:00.3. By optimized method of Agrobacterium-mediated transformation in vivo, the target gene, EPSPS-G6, was transferred into the extending upland cotton cultivar, ZMS 49, and 14.3 kg transferred cotton seeds was obtained. After spraying of 20 mM glyphosate, the survived seedlings rate was 22.18%. After PCR identification,35 transgenic cotton plants (To) with EPSPS-G6 were obtained.4. The segregation rate of resistant plants in Ti was ranging from 1/4 to 3/4. After selfing of the positive plants individually, the stable-resistant lines in T2 families were about 19.8-32.1%, basically corresponded the separation law of one pair heterozygous genes.5. Glyphosate tolerance tests showed that the resistant levels of the transgenic cotton germplasms with EPSPS-G6 were three times more than that of recommendatory dose for weed control, which was much better than that of American cotton germplasm with GESPS gene as well as the first generation of transgenic cotton germplasm developed in our lab with the same gene.6. The yield and agronomic characters of the transgenic cotton germplasms in present work were similar with the control, ZMS 49, with a slight higher in boll weight and seed index, and slight lower in plant height, fruit branch numbers. The fiber length, micronaire and fiber uniformity of the transgenic cotton germplasms were slightly better than that of control, and their fiber strength was similar with control, and their elongation was slightly lower than that of control. It was indicated that the foreign gene would not influence to the yield, fiber quality, and other agronomic characters of the transgenic cotton germplasm with EPSPS-G6.7. In this study, the occurrence and weed-control costs in Jinhua were investigated and surveyed for the utilization of the glyphosate resistant cotton cultivars in cotton production.. The results shown that goosegrass, portulacaceae and horseweed were the dominant weeds in cotton fields in Jinhua, and the chemical weed control could reduce about 1000 RMB each mu instead of hand controlling. So it is obvious that the application of highly glyphosate-resistant cotton cultivars could make a significant economic benefits, which a broad production and marketing prospect. |
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