Link to home

Assessment of Laboratory Methods for Evaluating Potato Tubers for Resistance to Late Blight

April 1998 , Volume 82 , Number  4
Pages  442 - 446

Anne E. Dorrance , Department of Plant Pathology, The Ohio State University-OARDC, 1680 Madison Ave., Wooster 44691-4096 , and Debra Ann Inglis , Washington State University, Mount Vernon-Research and Extension Unit, 1468 Memorial Highway, Mount Vernon 98273

Go to article:
Accepted for publication 17 January 1998.

Two laboratory methods (whole tuber and tuber slice) were evaluated and compared with field assessment of potato tubers for resistance to late blight caused by Phytophthora infestans. Altogether, the resistance responses of 20 cultivars and advanced selections were compared by the three methods. All three assays separated materials into resistant and susceptible groups. The majority of cultivars and advanced selections did not react in the same way within the field and tuber-slice assays but did react similarly within the whole-tuber assay. Some cultivars were susceptible in the field at harvest but were resistant in the whole-tuber assay. The differences may be due to the extent of lenticel and eye development during tuber formation. In contrast, other cultivars resistant in the field at harvest were susceptible in the whole-tuber assay. In this case, placement in the hill may affect whether or not the tuber is exposed to inoculum or whether aging of tubers during storage affects susceptibility to tuber blight. Our study shows that high levels of tuber resistance are available in certain commercial cultivars and advanced potato selections. For laboratory assessments to be reliable, however, both pre- and poststorage evaluations may be necessary.

Additional keyword: Solanum

© 1998 The American Phytopathological Society