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Diallel Analysis of Potato Leafhopper Resistance Among Selected Alfalfa Clones

Soper, J. F., McIntosh, M. S., Elden, T. C.
Crop science 1984 v.24 no.4 pp. 667-670
Empoasca fabae
The quantitative genetics of potato leafhopper Empoasca fabae (Harris) resistance among selected alfalfa (Medicago sativa L.) clones from three different alfalfa populations (Arc-PLH1, B16 Syn.I-PLH1, and Indiana Syn. C) was studied. Resistance was measured using no-choice laboratory screening techniques. Feeding damage after 1 and 2 weeks of exposure to leafhopper adults (FD-1 and FD-2, respectively) and subsequent nymphal populations were measured. A 10-parent diallel analysis was performed to detect combining ability effects for the resistance characteristics. General combining ability effects were significant for FD-1 and the number of nymphs. Specific combining ability effects were significant for the number of nymphs. Midparent-offspring regression analyses were performed to obtain narrow sense heritability estimates for the resistance characteristics. The estimates obtained were 0.31, 0.31, and 0.56 for FD-1, FD-2, and the number of nymphs, respectively. A positive phenotypic correlation was found between FD-1 and FD-2 (r ~ 0.73**) (**significant at the 0.01 level.). The number of nymphs was negatively correlated with high levels of FD-I (r = -0.49**), but was not correlated with FD-1 at low or moderate levels. Results indicate that further improvements in potato leafhopper resistance as measured by these characteristics can be made in populations derived from the selected alfalfa clones