Studies On The Character Of Disease Development And Rational Judgement Of Durable Resistance Wheat Cultivar Against Stripe Rust

The disease development regulation of wheat that durably resistant to stripe rust was researched in Longnan, Gansu,where the stripe rust occurred and mutated most frequently compared with else where in China. 10 cultivars which have been cultivated for many years were compared in characteristics of disease development in adult stage in the fields,among them some without losing resistance to stripe rust while others losing resistance to stripe rust. The 10 cultivars are all susceptible to stripe rust, their infection type is 3~4, but their latent period,infection frequency,spread speed of uredinia,disease index,damage rate of 1000 kernels weight,severity and prevalence are all different among them. The infection frequency,spread speed of uredinia,disease index,damage rate of 1000 kernels weight,severity and prevalence of durable resistance Libellula and N.Stranpelli were very less, and their latent period is long. the severity of Xiannong 4 and Qingnong 3 was very less while their prevalence has rapid increased after June 6; the severity and prevalence of other cultivars were very more after about 10 days. Libellula ,N.Stranpelli andXiannong 4 were all durable resistance to stripe rust ,but their mechanism of resistance to stripe rust are different.Less damage rate of 1000 kernels weight is common characteristic in the cultivars, it is abnormal correlation with latent period, the coefficient of abnormal correlation is significant at 0.01 level, and it is normal correlation with disease index, the coefficient of normal correlation is significant at 0.05 level. Cluster analysis depended on the above items is done by digital process system(DPS), and the judge fuction is preliminarly built for judgement of durable resistance wheat cultivar against stripe rust. Susceptible to stripe rust, long latent period,less infection frequency,spread speed of uredinia,disease index,damage rate of 1000 kernels weight,severity and prevalence are the characteristics of durable resistance cultivars, however the reverse is right or not, which should have been profoundly study in molecular mechanism.