Evaluation of Damping-Off Tolerance in Spinach Cultivars in Field Soils and in a Standardized Lab Assay with Pythium ultimum
Evaluation of Damping-Off Tolerance in Spinach Cultivars in Field Soils and in a Standardized Lab Assay with Pythium ultimum
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DOI：
10.1094/php-07-21-0107-rs
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发表时间：
2022-05-16
影响因子：
2.3
通讯作者：
Scholten, Olga E.
中科院分区：
文献类型：
--
作者：
Magnee, Kim J. H.;Postma, Joeke;Scholten, Olga E.
由于对化学处理的限制越来越多，菠菜种植者在新鲜市场（嫩叶）菠菜的生产中面临越来越多的立枯病问题。抗病品种越来越重要，需要适当的评价方法。从荷兰三个有菠菜种植历史的地方和法国一个地方，从土壤中分离出潜在的立枯病病原体，鉴定为种或属，并测试其致病性。终极腐霉是最普遍的病原体在这些领域，导致菠菜前和出苗后猝倒。8个菠菜品种，每个品种有两个或三个种子批次进行了评估，在相同的领域的位置，并在温室中与土壤采样从荷兰的现场之一。出苗前猝倒比出苗后猝倒更能区分品种间的差异。相同品种的试验、重复和种子批之间感染水平的变化强调了需要更标准化的表型分析。对于这样的测定，将具有致病性终极疫霉分离物的基于玉米粉-砂的接种物添加到砂、蛭石和蛭石的基质混合物中，并润湿直至50%持水能力，其中将菠菜种子在15 ° C的黑暗气候箱中孵育10天，包括没有终极疫霉接种物的对照处理。该测定法显示了可重复的结果，用于区分种子批次之间出苗前猝倒病耐受水平的差异。然而，品种差异出苗前猝倒耐受水平不能被证实，由于种子批次之间的差异很大，需要进一步调查。
Spinach growers face increasing problems of damping-off in the production of fresh-market (baby-leaf) spinach due to increasing restrictions on chemical treatments. Damping-off-tolerant cultivars are increasingly important, requiring proper evaluation methods. From three locations in The Netherlands with a history of spinach cultivation and from one location in France, potential damping-off pathogens were isolated from the soil, identified to species or genus, and tested for their pathogenicity. Pythium ultimum was the most prevalent pathogen in those fields, causing spinach pre- and postemergence damping-off. Eight spinach cultivars with two or three seed lots each were evaluated at the same field locations and in a greenhouse with soil sampled from one of the Dutch field sites. Preemergence damping-off was more discriminating for differences among the cultivars than postemergence damping-off. Variation in levels of infection among trials, replicates, and seed lots of the same cultivars emphasized the need for a more standardized phenotyping assay. For such an assay, a cornmeal-sand-based inoculum with a pathogenic P. ultimum isolate was added to a substrate mixture of sand, perlite, and vermiculite and moistened until 50% water-holding capacity, in which spinach seeds were incubated for 10 days in a dark climate cabinet at 15 degrees C, including a control treatment without P. ultimum inoculum. The assay showed reproducible results for discriminating differences in preemergence damping-off tolerance levels among seed lots. However, cultivar differences in preemergence damping-off tolerance levels could not be confirmed due to a large variation among seed lots that needs further investigation.