Race Dynamics Analysis of Puccinia Graminis f.sp. tritici in Chinain 1994

Yao Ping Cao Yuanyin Liu Weizhi Wu Yousan (Plant Immunological Laboratory of Shenyang Agricultural University, Shenyang 110161)

wheat stem rust; pathotype; virulence frequency

isolates were isolated from 136 survival samples out of 201 raw samples collected from 83 wheat cultivars in 35 counties of 8 provinces or autonomous regions in 1994. After indentified, the 332 isolates belonged to races 21C3, 34, 34Cl and 34C2 or pathotypes 21C3CKR, 21C3CKH, 21C3CTR, 21C3CTH, 21C3CPR, 21C3CFR; 34MFG, 34MKG;34C1MKR, 34C1MKH; 34C2MKR, 34C2MKK,34C2MFK, 34C2MKH, respectively. The highest occur rence frequency race was 21C3(77.0%), next was 34C2(16.1%), following them were races 34(6%), 34C1(0.9%). The highest occurrence frequency pathotype was 21C3CKR (31.6%), following it were 21C3CTR (3.0%), 21C3CKH(4.8%), 21C3CPR(4.8%), 21CTH (3.0%), 21C3CFR (1.2%), 21C3CPH (0.6%), 34MKG (3.9%), 34MFG (2.1%), 34C1MKR (0.6%), 34C1MKH (0.3%), 34C2MKR (6.7%), 34C2MKK(5.8%), 34C2MKH(3.0%), 34C2MFK (0.6%),Pathotype 21C3CTR increased rapidly and had occurred in Yunnan, Sichuna, Hubei, Henan, Hebei and Gansu Provinces since found in 1993. 34C2 was relatively stronger virulent race and its occurrence frequency was little higher in 1993, although it occurred only locally.