Wheat lines exhibiting variation in tolerance of Septoria tritici blotch differentiated by grain source limitation
Wheat lines exhibiting variation in tolerance of Septoria tritici blotch differentiated by grain source limitation
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DOI：
10.1016/j.fcr.2017.11.022
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发表时间：
2018-03-01
影响因子：
5.8
通讯作者：
Foulkes, M. J.
中科院分区：
文献类型：
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作者：
Collin, F.;Bancal, P.;Foulkes, M. J.
小麦黑斑病（STB）是欧洲最具破坏性的小麦病害。由于基因型抗性的部分性质或对杀菌剂的抗性增强，耐受性，即在表达的疾病存在下保持产量，是一个相关的替代方案。耐受性通常是通过每单位来源减少的产量损失来估计的，以前观察到的基因型之间的耐受性对比表明，增加来源可利用性或改善储存同化物的利用都可以提高耐受性。本文旨在建立源/汇方法来了解STB的耐受性机制，并确定潜在的性状来提高STB的耐受性。通过田间试验，探讨了源汇平衡与STB容忍度的关系。以6个小麦基因型为研究材料，对比了它们对STB自然侵染的耐受性，通过晚施氮肥和去除50%小穗来改变源库平衡。基因型的耐受性在另外三个田间试验中进行了定量估计。我们发现，对STB的耐受性与健康作物的性状（单粒重高，绿叶层面积占叶片3的比例高，旗叶=叶片1）相关。结果表明，6个基因型对籽粒灌浆的源限制程度差异很大。因此，我们提出了一个易于计算的指标，该指标与STB耐受性的劳动强度估计高度正相关。潜在产量与耐受性不相关，表明对产量性能和耐受性的选育是可能的。
Septoria tritici blotch (STB) is the most damaging disease of wheat crops in Europe. Because of the partial nature of genotypic resistance or the increasing resistance against fungicides, the tolerance, i.e. maintaining yield in the presence of expressed disease, is a relevant alternative. Tolerance is generally estimated through the yield loss per unit of source reduction, contrasts of tolerance between genotypes have been observed previously suggesting that either increasing the source availability or improving the use of stored assimilate could improve tolerance. This paper aims at developing a source/sink approach to understand the tolerance mechanism and identifying potential traits to increase tolerance of STB. A field experiment was designed to explore the relation between tolerance of STB and source/sink balance. Based on six wheat genotypes contrasting for tolerance exposed to natural STB epidemics, late nitrogen fertilization and a 50% spikelet removal were applied to change the source/sink balance. The tolerance of genotypes was quantitatively estimated over three additional field experiments. We found that STB tolerance was correlated with traits of healthy crops (high individual grain weight and high proportion of green leaf lamina area as leaf 3; flag leaf = leaf 1). The spikelet removal revealed a highly variable degree of source limitation for grain filling amongst the six genotypes. Thus, we proposed an easily calculated index that highly correlated positively with the labor intensive estimation of STB tolerance. Finally, potential yield and tolerance were not correlated, which suggests that breeding for yield performance and tolerance could be possible.