Wharton Phillip S, Iezzoni Amy, Jones Alan L
Department of Plant Pathology.
Department of Horticulture.
Plant Dis. 2003 May;87(5):471-477. doi: 10.1094/PDIS.2003.87.5.471.
A detached leaf disk assay was developed for screening sour cherry (Prunus cerasus) cultivars for resistance to cherry leaf spot (Blumeriella jaapii). This assay was used to characterize the events occurring in cv. Montmorency (susceptible) and cv. GiSelA 6 [GI 148-1] (resistant) host-pathogen interactions, and to develop a disease scoring scheme to categorize disease severity in sour cherry trees. Forty-three seedlings grown from seeds collected in Russia were screened for resistance using the scoring scheme. Cross infection studies were also carried out with leaf spot isolates from four other Prunus species. These studies were made possible by the development of a new method of culturing B. jaapii isolates, using cherry fruit agar. This method enabled large amounts of inoculum to be produced within 2 weeks rather than a couple of months as required previously. In 'Montmorency', disease symptoms were first observed 4 days postinoculation (dpi), with the appearance of small white spots on the undersides of inoculated leaves. These spots gradually grew, producing erumpent spore masses in acervuli approximately 7 dpi. In 'GI 148-1', disease symptoms were also first observed 4 dpi, with the appearance of small transparent lesions. In the majority of cases, these lesions did not increase in size; however, acervuli occasionally were formed approximately 8 dpi. These contained small cirrhi and were often surrounded by an abscission zone. Of the sour cherry seedlings tested, only 'Almaz' open pollinated (o.p.) R1(1) was rated as resistant. 'Almaz' o.p. R1(1) and 'GI 148-1' were also rated as resistant to leaf spot isolates from other Prunus species. These results and the implications for breeding resistant sour cherry cultivars are discussed.
开发了一种离体叶盘测定法，用于筛选酸樱桃（Prunus cerasus）品种对樱桃叶斑病（Blumeriella jaapii）的抗性。该测定法用于表征在蒙莫朗西品种（易感）和吉塞拉6号品种[GI 148 - 1]（抗病）的宿主 - 病原体相互作用中发生的事件，并制定一种病害评分方案，以对酸樱桃树的病害严重程度进行分类。使用该评分方案对从俄罗斯收集的种子培育出的43株幼苗进行了抗性筛选。还对来自其他四种李属物种的叶斑病菌株进行了交叉感染研究。这些研究得益于一种使用樱桃果实琼脂培养B. jaapii菌株的新方法的开发。这种方法能够在2周内产生大量接种物，而不是像以前那样需要几个月的时间。在“蒙莫朗西”品种中，接种后4天（dpi）首次观察到病害症状，接种叶片的下表面出现小白点。这些斑点逐渐扩大，在大约7 dpi时在分生孢子盘上产生突破表皮的孢子团。在“GI 148 - 1”品种中，接种后4 dpi也首次观察到病害症状，出现小的透明病斑。在大多数情况下，这些病斑大小没有增加；然而，大约8 dpi时偶尔会形成分生孢子盘。其中含有小的卷须，并且常常被离层带包围。在所测试的酸樱桃幼苗中，只有“阿尔玛兹”开放授粉（o.p.）R1(1)被评为抗病。“阿尔玛兹”o.p. R1(1)和“GI 148 - 1”对来自其他李属物种的叶斑病菌株也被评为抗病。讨论了这些结果以及对培育抗病酸樱桃品种的意义。
