Selection for resistance to Colletotrichum trifolii in the lucerne cultivars Hunter River and Siro Peruvian

Abstract

Seedlings of lucerne (Medicago sativa) with increased resistance to anthracnose caused by Colletotrichum trifolii, were obtained from cvv. Hunter River and Siro Peruvian by selection through two generations under laboratory conditions. Glasshouse screening of half sib F1 and F2 families confirmed that rapid progress was made in increasing the level of resistance in both populations. In the field, after two years, F1 derivatives had lower percentages of plant mortality and disease indices than their parent cultivars, and F2 derivatives had lower values than their F1 parents. The F2 population of Siro Peruvian, in the second year, yielded 55% and 45% more dry matter than the unselected populations of Siro Peruvian and Hunter River respectively. However, the level of resistance in the field of the Siro Peruvian F2 population was only the equivalent of the unselected Hunter River population, and was inferior to the F1 and F2 populations of Hunter River.