关键词: 巴西固氮螺菌, 巴西固氮螺菌, 增强型绿色荧光蛋白（EGFP）, 表达载体, 实时荧光定量PCR (qRT-PCR)

Abstract: In order to explore the operating mode and quantitative indicators for family farms of multiple cropping of rice- rape, a comprehensive analysis of costs and benefits of the rice- rape production was conducted based on the reported network data of 990 family farms from 22 counties in Hunan Province and the survey data of 135 family farms in Hunan Province. Using family members as the main labor resources, the operating modes for family farms of multiple cropping of rice-rape were put forward. The results showed that the optimum scales of family farm which owned agricultural machinery and family farms using outsourcing mechanical job were 9 and 11 hm2, respectively. The results provide a theoretical basis for the scale of family farms of multiple cropping of rice-rape in southern China.