OXALIC-ACID EFFECTS IN EXUDATES OF SCLEROTINIA-TRIFOLIORUM AND S-SCLEROTIORUM AND POTENTIAL USE IN SELECTION

被引:12
作者
ROWE, DE
机构
关键词
D O I
10.2135/cropsci1993.0011183X003300060007x
中图分类号
S3 [农学(农艺学)];
学科分类号
0901 ;
摘要
Sclerotinia crown and stem rot caused by Sclerotinia trifoliorum Eriks. or S. sclerotiorum (Lib.) de Bary is a serious problem on crimson clover (Trifolium incarnatum L.), berseem clover (T. alexandrinum L.), and alfalfa (Medicago sativa L.) in temperate climates. The inability to develop cultivars resistant to this disease indicates more detailed research is needed on factors causing disease by either fungus. The objectives of this study were to determine what deleterious effects fungal exudates have on the seed of these legumes and attempt to measure the importance of oxalic acid in the fungal exudates. The percent seed germination and length of germinated seedlings of four cultivars each of crimson clover, berseem clover, and alfalfa were measured in five environments. Seed was placed in a host-pathogen interaction system and exposed to exudates of S. trifoliorum or S. sclerotiorum on water agar acidified with oxalic acid to a pH of 3.3, and water agar as a control (pH 6.2). In contrast to a control, fungal exudate caused a 51 to 60% reduction in seedling length and an average of two-thirds of this reduction appeared to be caused by oxalic acid. The seedling length on oxalic acid amended agar was correlated with that of seedlings exposed to exudates from S. trifoliorum (r = 0.71, 10 df) and S.sclerotiorum (r = 0.83, 10 df). Oxalic acid appeared to have potential value in selection of resistance to either fungus in alfalfa or resistance to S. sclerotiorum in crimson clover.
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页码:1146 / 1149
页数:4
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