VIEW ARTICLE

Resistance

Inheritance of Resistance to Virus-Induced Lethal Wilt in Arrowleaf Clover. I. J. Pemberton, Research assistant, Texas Agricultural Experiment Station, Texas A&M University Agricultural Research and Extension Center, Overton 75684; M. R. McLaughlin(2), and G. R. Smith(3). (2)Research plant pathologist, U.S. Department of Agriculture, Agricultural Research Service, Crop Science Research Laboratory, Forage Research Unit, Mississippi State 39762; (3)Associate professor, Texas Agricultural Experiment Station, Texas A&M University Agricultural Research and Extension Center, Overton 75684. Phytopathology 81:1001-1005. Accepted for publication 30 April 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-1001.

Inheritance of the lethal wilt (LW) reaction in arrowleaf clover inoculated with a pea mosaic-type virus (PMV) isolate, 204-1, of the bean yellow mosaic virus (BYMV) subgroup was investigated. The expression of LW was found to be simply inherited and conditioned by a single dominant gene (L). Resistance to LW was conferred by the homozygous recessive form of the gene. Interaction of the L gene with five other BYMV subgroup isolates was also studied. Germ plasm tested included LW-resistant (family 3-97; ll) and -susceptible (Yuchi; ~20% LL or LI) populations of arrowleaf clover. The LW reaction in arrowleaf clover is virus strain-specific, and only one other isolate, TX-22, induced LW in susceptible arrowleaf clover. Lethal wilt did not occur when susceptible arrowleaf clover was inoculated with BYMV-Scott, BYMV-RC, TX-3, and clover yellow vein virus (CYVV-Pratt) isolates. Plants in the family 3-97 did not express LW when inoculated with any of the six isolates. Plants resistant to the LW syndrome were susceptible to infection with all the virus isolates tested and developed symptoms consisting of varying degrees of nonlethal wilting and systemic mosaic.