Date Published: May 21, 2019
Publisher: Public Library of Science
Author(s): Chunyu He, Yanhong Zhang, Wei Zhou, Qingyi Guo, Bin Bai, Sanbao Shen, Gaobao Huang, Wujun Ma.
Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an airborne fungal disease which always destructs leaf and leads to stagnation of grain filling, decreasing of kernel weight, thin seed and yield loss. Winter wheat Huixianhong is a special germplasm with special characteristics of tolerance or resistance against stripe rust. In order to understand the effect on Huixianhong from stripe rust, we designed two kinds of treatment, inoculation of stripe rust fungi (IH) and artificial immune by bactericide (CK) to study the dynamic of disease process, the grain filling and the thousand-kernel weight (TKW). Our results showed that the incubation period of Hongxinahui was 13.5 days. The prevalence increased from 32.9% at 15 days after jointing to 80.0% at 9 days after booting, and reached to 97.0% at the heading stage. The infection type (IT) was 7 to 9 at the beginning of anthesis. The severity, leaf withered area ratio and disease index at the 15th day after anthesis were 67.17%, 98.17% and 0.6717, respectively. The IH maximum increasing rate of leaf necrosis and chlorosis area was from heading beginning stage to anthesis beginning stage, which increased from 18.66 mm2·d-1 to 21.04 mm2·d-1. The maximum rate of grain filling was 1.25 mg·d-1 at the 18th day after anthesis, which was earlier than that of CK by 3.3 days. The IH thousand-kernel weight Loss (TKWL) was more than that of CK by 6.19%, the stage of heading and amature were 3.0 days and 4.5 days earlier than CK, respectively. The stripe rust infection seriously destructed the photosynthetic function of leaf at the earlier stage of grain filling, i.e. at the beginning of anthesis, which led to the most important biomass loss and the grain filling rate decrease. As far as stripe rust is concerned, Huixianhong is a high susceptible, easily been infected, seriously showing symptoms and most quickly epidemic type but can successfully complete grain filling in high quality. It is a very useful germplasm for creating and selecting special breeding materials against stripe rust.
Epidemics of wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, are more frequent around the world and often led to serious yield loss while applying for the resistance wheat cultivar or materials can significantly decrease leaf damage and yield loss. So how to find and breed excellent wheat materials and cultivar is very important for wheat breeding and production. The winter wheat cultivar Huixianhong is the typical one with more excellent characteristics and been found by Dr. Chunyu He.
Knowledge of crop physiology in terms of grain yield determination enhances the efficiency of crop management programs. Decisions about fungicide applications during grain filling would also be based on knowledge of crop physiology. If source limitation takes place during the active grain-growth phase, grain weight could be affected by source limitation to growing grains. Conversely, if the diseases affect the assimilate supply during the lag phase, grain weight potential could be affected without effects on assimilation supply .
Huixianhong characteristics are susceptible, highly susceptible, recurrent and rapid epidemic types of stripe rust. The leaf source of Huixianhong has lost at the early stage of grain filling due to the infection of stripe rust. Because of its own special grain filling mechanism, this variety could guarantee grain filling normally and maintain a low loss rate of thousand-kernel weight, and it is helpful for screening in stripe rust resistant breeding materials.