国家自然科学基金No.41171203;陕西省科技统筹创新工程计划项目No.2011KTCL02-15;公益性行业农业科研专项No.201303094 Supported by the National Natural Science Foundation of ChinaNo.41171203,the Innovation of Science and Technology Plan Projects of Shaanxi ProvinceNo.2011KTCL02-15and the Special Fund for Ago-scientific Research in the Public InterestNo.201303094