Potato leafhopper causes considerable damage in red clover. The main objectives of this study were to clarify the inheritance of pubescence and to evaluate the relationship between pubescence and potato leafhopper (Empoasca fabae (Harris) resistance. Thirteen red clover clones of diverse origin, including both pubescent and non-pubescent types were used as parents. A series of crosses were made in all possible combinations among the 13 parental clones. Seedlings of F$ sb1$ progeny and stem cuttings from parents were planted in the field in the summer of 1993 in a randomized complete block design. Based on the results, the inheritance of pubescence type on red clover stems, petioles and abaxial leaf surfaces was best explained individually by two-locus models showing dominant and recessive interaction. A two locus model with recessive epistasis was proposed for pubescence on stipules and basal internodes, but there were a number of crosses that deviated from expected ratios. There was quantitative variation for trichome density on red clover and it appeared to be inherited as a quantitative trait. Based on mid-parent offspring regression, the heritability estimates of trichome density on petioles, stems, abaxial leaf surfaces, and adaxial leaf surfaces were 0.16, 0.77, 0.50 and 0.48, respectively. Pubescence was apparently associated with potato leafhopper resistance. Visual ratings of feeding injury, the numbers of leafhopper nymphs per plant and the numbers of nymphs per gram of dry plant material were higher on glabrous plants than on pubescent plants. (Abstract shortened by UMI.)

Bibliography: leaves 108-152 / viii, 152 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This study investigates the induction of resistance to the clover cyst nematode, Heterodera trifolii Goffart, an economic pest in white clover pastures that are a key to high milk yields in dairy cattle...it explores the potential of soil and rhizosphere bacteria to induce systemic resistance in white clover, Trifolium repens L. (summary) / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2000

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