Impact of sowing time, genotype, environment and maturity on biomass and yield components in faba bean (Vicia faba)

Abstract

Faba bean (Vicia faba L.) is a significant rotation crop in northern New South Wales. However, drought limits yield, and the reproductive structures of faba bean are sensitive to high temperatures and frost. Although early sowing can avoid terminal heat and drought stresses, the accumulation of large amounts of vegetative biomass may result in low yield. Experiments were conducted over 2 years at Breeza and Narrabri in north-western New South Wales, Australia, to examine the influence of sowing time on yield, yield components, maturity, pod distribution and biomass production. The second sowing date (early May) produced the highest yield and seed weight at both sites. However, the third sowing date (late May) produced greater yield than the first (mid-April) at Breeza, and this was associated with very high final biomass. At Narrabri, the first and third sowing dates produced similar low yield. Poorer yield in late-sown materials was likely due to terminal stress, and the impact will be greater in less favourable locations and seasons. The poorer yield of faba bean from the first sowing date was likely driven by excessive biomass accumulation, an effect that would be exacerbated in favourable seasons and locations. The lower seed weight observed at Breeza was possibly a result of greater intra-plant competition. The earliest maturing genotype had the highest yield and seed weight at both sites, indicating the importance of rapid pod growth and senescence in these warm and often water-limited environments. Dry matter production was greater with early sowing, higher moisture and warmer temperatures. In contrast to other studies, a weak relationship between biomass and yield was observed.