The Development of Asparagus Somaclones with High Levels of Resistance to Fusarium oxysporum f. sp. asparagi and F proliferatum. Yinghui Dan, Former Graduate Assistant; Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824. C. T. Stephens, Professor, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824. Plant Dis. 79:923-927. Accepted for publication 18 May 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0923.

Asparagus somaclones were produced by subculturing shoots initially generated from callus-derived protoplasts of Asparagus officinalis cv. Lucullus 234 through callus cycles for more than a 3-year period. One hundred twenty protoplast-derived somaclones of Lucullus 234 were screened for resistance to two virulent Michigan isolates of Fusarium oxysporum f. sp. asparagi (FOA10 and FOA50) and F. proliferatum (FM12 and FM49) in the greenhouse. Soma-clones had significantly (P< 0.05) more resistance to the Fusarium spp. than did the vegetatively micropropagated plants of the parental cultivar Lucullus 234. Of the somaclones that contained higher levels of disease resistance, a minimum of 12 micropropagated plants from each were produced and rescreened for resistance to the most virulent isolate (FOA50) among the four isolates tested in the greenhouse. Two somaclonal lines, R7 and R4, were highly significantly (P < 0.01) more resistant to the FOA50 of F. o. f. sp. asparagi than were the vegetatively micropropagated parental plants. No morphological or growth differences were observed between these lines and the parental cultivar.

Keyword(s): asparagus decline, tissue culture