Abstract Arbuscular mycorrhizal fungi (AMF) play an important role in phosphorus (P) nutrition of plants. Varietal differences in AMF infection occur but there is limited information on the importance of these differences to P efficiency in wheat. This work was conducted to determine whether variation in AMF infection could help explain genetic differences in responses to P. Ten wheat varieties that vary in their grain yield response to P were compared at different rates of P in two controlled environment experiments. Plant samples were also collected from a field experiment with two P rates. Significant genetic variation was observed for AMF colonization in all experiments, but these differences were not consistently related to the yield responsiveness to P among the ten varieties. Two varieties, Carazinho and RAC875 that have a low yield response to P, had consistently high root colonization while a P-responsive variety, Wyalkatchem, had low root colonization. Adding P fertilizer reduced AMF colonization and at high P rates negative associations between AMF colonization and seedling growth and P uptake were observed among the varieties. Among some varieties, their grain yield response to P and P efficiency were consistent with their AMF colonization. However, the negative effect of mycorrhizal infection on seedling growth at high soil P suggests AMF colonization may only be a suitable trait for improved P efficiency in farming systems where available P is consistently low.

中文翻译：

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对磷反应不同的面包小麦品种的菌根定植

摘要 丛枝菌根真菌（AMF）在植物磷（P）营养中起着重要作用。AMF 感染存在品种差异，但关于这些差异对小麦磷效率的重要性的信息有限。进行这项工作是为了确定 AMF 感染的变异是否有助于解释对磷的反应的遗传差异。在两个受控环境实验中，对不同磷含量的 10 种小麦品种对磷的谷物产量反应进行了比较。植物样品也是从田间试验中收集的，具有两种 P 率。在所有实验中都观察到 AMF 定植的显着遗传变异，但这些差异与 10 个品种之间对磷的产量响应性并不一致。两个品种，Carazinho 和 RAC875 对磷的产量反应较低，根系定植率一直很高，而对磷有反应的品种 Wyalkatchem 的根定植率较低。添加磷肥减少了 AMF 的定植，并且在高磷率下，在品种中观察到 AMF 定植与幼苗生长和磷吸收之间存在负相关。在一些品种中，它们的谷物产量对磷和磷效率的反应与其 AMF 定植一致。然而，菌根感染对高磷土壤幼苗生长的负面影响表明，在可用磷始终较低的农业系统中，AMF 定植可能只是提高磷效率的合适性状。添加磷肥减少了 AMF 的定植，并且在高磷率下，在品种中观察到 AMF 定植与幼苗生长和磷吸收之间的负相关。在一些品种中，它们的谷物产量对磷和磷效率的反应与其 AMF 定植一致。然而，菌根感染对高磷土壤幼苗生长的负面影响表明，在可用磷始终较低的农业系统中，AMF 定植可能只是提高磷效率的合适性状。添加磷肥减少了 AMF 的定植，并且在高磷率下，在品种中观察到 AMF 定植与幼苗生长和磷吸收之间的负相关。在一些品种中，它们的谷物产量对磷和磷效率的反应与其 AMF 定植一致。然而，菌根感染对高磷土壤幼苗生长的负面影响表明，在可用磷始终较低的农业系统中，AMF 定植可能只是提高磷效率的合适性状。