Seedling resistance to spotted alfalfa aphid of lucerne and annual medic species in Victoria

Abstract

Fifty lines of lucerne and 15 lines of annual Medicago spp. were tested for seedling resistance to Therioaphis trifolii (Monell) f. maculata in glasshouse tests at Burnley, Victoria. Thirty-seven lines of lucerne from the USA were tested and of these, 36 had greater (P < 0.05) seedling survival than M. sativa cv. Hunter River, while 29 had greater (P < 0.05) seedling survival than M. sativa cv. Falkiner. The results demonstrated that lucerne cultivars selected for resistance to North American biotypes of the aphid were resistant to the Victorian aphid population. The lucerne seedling screening technique was successfully adapted for annual medics. There was a wide range of reaction to aphids between the 13 lines of M. truncatula tested. However, no lines were superior to cv. Jemalong. Surviving seedlings in this species were generally stunted, unlike M. rugosa cv. Paragosa, where very little seedling damage occurred.