Stem rot caused by Sclerotium rolfsii is a destructive disease that induces serious yield losses in groundnut (Arachis hypogaea L.) around the world. This study used a multifaceted approach to screen 121 groundnut genotypes from different subspecies and botanical varieties for resistance to S. rolfsii under field conditions. Five wild species of Arachis were also assessed in a greenhouse study. In both experiments, 60 to 65 days after planting, plants were inoculated with an aggressive isolate of S. rolfsii using a combined agar disk technique. Disease assessments were made using a disease score (DS) scale of 1 to 5 based on the percentage of symptomatic plants. The genotypes and wild species were also screened using a SSR marker associated with fungal resistance. In the first year of study, significant variations were observed among the genotypes with respect to disease related traits. The DS results varied from 2 to 5 with a general mean of 4.7. Under heavy disease pressure, 5.7% and 1.6% of the collection were found to be moderately susceptible and moderately resistant, respectively. In the second year of study, the selected moderately susceptible and moderately resistant genotypes were assessed in similar field conditions. The overall result showed that the lowest DS was observed in the genotypes ACG 14 and ACG 101, from subsp. fastigiata var. vulgaris and var. subsp. hypogaea var. hypogaea, respectively. They also had similar pod yield with controls. For the wild Arachis species, the average DS was 3.7, A. batizocoi having the lowest DS of 2.5, followed by A. duranensis and A. cardenasii. There was no correlation between the molecular marker analysis and field phenotyping. New validated resistance related markers should be developed for further studies to select truly resistant/susceptible genotypes.

中文翻译：

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花生收集物对由 Sclerotium rolfsii 引起的茎腐病的表征

由 Sclerotium rolfsii 引起的茎腐病是一种破坏性病害，会导致世界各地的花生 (Arachis hypogaea L.) 严重减产。本研究采用多方面的方法筛选来自不同亚种和植物品种的 121 种花生基因型，以确定在田间条件下对 S. rolfsii 的抗性。在温室研究中还评估了花生的五种野生物种。在这两个实验中，在种植后 60 到 65 天，使用组合琼脂盘技术用 S. rolfsii 的侵袭性分离株接种植物。基于有症状植物的百分比，使用 1 到 5 的疾病评分 (DS) 量表进行疾病评估。还使用与真菌抗性相关的 SSR 标记筛选基因型和野生物种。在学习的第一年，在疾病相关性状方面观察到基因型之间的显着差异。DS 结果从 2 到 5 不等，一般平均值为 4.7。在重病压力下，分别发现 5.7% 和 1.6% 的藏品具有中度敏感和中度抗性。在研究的第二年，在相似的田间条件下对选定的中度敏感和中度抗性基因型进行了评估。总体结果表明，在来自亚种的 ACG 14 和 ACG 101 基因型中观察到最低的 DS。fastigiata 变种 普通和变种。亚种 海棠变种 分别为hypogaea。他们也有与对照相似的豆荚产量。对于野生花生物种，平均 DS 为 3.7，A. batizocoi 的 DS 最低，为 2.5，其次是 A. duranensis 和 A. cardenasii。分子标记分析与田间表型之间没有相关性。应开发新的经验证的抗性相关标记，用于进一步研究以选择真正抗性/易感基因型。