江苏省科技支撑计划农业项目BE2013441;“江苏省六大人才高峰”高层次人才项目2012-NY-032;江苏省2015年度普通高校研究生实践创新计划项目SJLX15_0299;南京市科技计划项目201505059共同资助[This work was supported by the Jiangsu Province Science and Technology Agricultural Support ProgramBE2013441;Jiangsu Province Six Talent Peaks of High Level Talents Project2012-NY-032;the Innovation of Graduate Student Training Project of Jiangsu Province in 2015SJLX15_0299;Science and Technology Plam Projects 201505059]