Boron for brown-heart control on two rutabaga cultivars

Field experiments were carried out in Prince Edward Island to investigate the effect of broadcast and foliar B applications on brown-heart, leaf nutrient content, yield and storage of two rutabaga cultivars (Brassica napabrassica Mill.) at one site in 1994, 1996 and 1997. The two cultivars, York and Thomson Laurentian, were seeded with preplant broadcast B at 0, 2.24, 4.48 and 6.72 kg ha(-1). Within each preplant broadcast B treatment, foliar B was applied as Solubor (20.5% B) at 0 and 2.24 kg B ha(-1). Foliar B was applied 28 and 42 d after seeding at 1.12 kg B ha(-1) at each application. Averaged over these 3 yr, total yield was reduced by broadcast B and foliar B applications. Applications of B increased soil and tissue B levels. Boron was within acceptable levels for plant tissue and soil in all years; however, brown-heart was severe in 1994. On average, the incidence of brown-heart was lower in York than in Thomson Laurentian, and further decreased with increasing rate of B, both broadcast and foliar.