LijieMa,XinyuKong,JiaxingQiao,FeiAn, XiaopingHu, Xiangming Xu.Overwintering of Puccinia striiformis f. tritici on Winter Wheat at Varying Altitudes in Gansu and Qinghai Provinces.

Overwintering of Puccinia striiformis f. tritici on Winter Wheat at Varying Altitudes in Gansu and Qinghai Provinces.

LijieMa,XinyuKong,JiaxingQiao,FeiAn, XiaopingHu, Xiangming Xu.

Plant Disease

DOI:10/1094/pdis-09-15-1112-RE

Abstract:  Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an important wheat disease in China. Pst overwintering and non-overwintering regions based on the temperature were described elsewhere. The temperature limit for Pst overwintering is derived from field observations. However, Pst has recently been observed to overwinter at sites where overwintering is predicted to be unlikely. We studied Pst overwintering across several sites in regions close to or further away from the current Pst ‘overwintering boundary’ in China. Plants with Pst symptoms and uredinia were tagged in late autumn and moved to laboratory in early spring the following year for quantification of Pst biomass via a qRT-PCR method and for assessment of Pst symptoms and sporulation after incubation in a greenhouse. The molecular method detected Pst in leaves and sheath in most samples, much greater than the observed incidence of Pst symptoms and sporulation after incubation. Further refinement may thus been necessary to calibrate this molecular methed in order to avoid overestimating P.striiformis f. Sp.tritici overwintering potential.Active sporulation (hence,successful overwintering)was observed for all sites except one.