Abstract:This study aimed to select the suitable varieties and the optimum sowing date of Avena sativa in Gande alpine region.The production performance and nutritional quality of seven oat varieties at four sowing dates (May 23,May 30,June 6,June 13,2020) were comprehensively evaluated using grey correlation and cluster analysis.The results showed that among all varieties with different sowing dates,the hay yield of Menglong sown on May 30 was the highest (20 022 kg/hm2),followed by Monika (19 835 kg/hm2),and Longyan No.3 sown on May 30 had the highest crude protein content (5.57%).With the delay of sowing date,the tiller number of seven oat varieties increased first and then decreased,and the stem base diameter decreased gradually.Based on the relative values of hay yield,crude protein content,neutral detergent fiber content,acid detergent fiber content and soluble sugar content,the comprehensive evaluation of grey correlation showed that Qinghai No.444 planted on May 23 had the best comprehensive performance,followed by Qingyin No.2 planted on May 30.There were four categories including high hay yield,low hay yield,high crude protein content and low crude protein content,according to the cluster analysis.