Reducing management inputs and maximising seed quality in faba beans through improved varieties

Abstract

Faba beans (Vicia faba L.) are a valuable break crop in southern Australia and the most profitable pulse on heavy soils prone to transient waterlogging in medium to high rainfall areas. Previous research indicates faba beans require early sowing to maximise yields and hence they are often dry sown before the season break. This increases crop exposure to disease infection, particularly ascochyta blight (Ascochyta fabae), chocolate spot (Botrytis fabae) and cercospora leaf spot (Cercospora zonata). Older cultivars (cv Fiord and Fiesta VF) have only low to moderate resistance to these diseases. Fungicides are expensive and not always entirely effective for disease control, resulting in reduced profitability through yield loss and quality downgrading. To improve yield stability and productivity the National Faba Bean Improvement Program has developed varieties with improved disease resistance and seed quality. Field experiments were conducted at two sites in South Australia to develop cost-effective disease management strategies for the new cultivars Farah and Nura. Disease levels were low to moderate in these experiments. Both new cultivars had lower levels of ascochyta blight foliar disease and seed staining than Fiesta VF, while Nura also had lower chocolate spot infection. Fungicide sprays generally reduced disease levels, particularly in Fiesta VF, roughly in relation to the total number of sprays applied. Fungicides gave a modest yield increase at one site only, but markedly reduced ascochyta seed stain in Fiesta VF and caused a small reduction in Farah at one site. The very low seed stain levels of Nura were not affected by fungicides. Varieties with improved disease resistance will provide low input, low risk options for early sowing practices of faba bean in southern Australia.