Planting date and suboptimal seedbed temperature effects on dry bean establishment, phenology and yield

Abstract

Seedbed temperatures below 15°C are detrimental to dry bean germination and emergence. This field study was conducted to determine the effects of suboptimal seedbed temperatures on dry bean emergence, and the cumulative effects of suboptimal seedbed temperatures during emergence on crop phenology and yield. Selected dry bean cultivars were planted in mid- and late May when seedbed temperatures were below and above the suboptimal temperature (15°C), respectively, at Saskatoon, SK. Emergence, cumulative thermal units to anthesis and maturity, seed yield, yield components and percent frost-damaged seeds were evaluated in 1999 and 2000. The final seedling count at 30 d after planting was 81% for the mid-May planting and 94% for the late May planting. However, the difference in plant stand was not statistically significant. Year-to-year differences in weather influenced the response of dry bean to planting date for maturity and seed yield. The mid-May planting produced the highest seed yield in 1999, when the two indeterminate cultivars in the late May planting failed to mature prior to the mid September frost. The mid-September frost also resulted in a high percent frost-damaged seeds for the late May planting. In 2000, when the first fall frost was in late September, maturity and seed yield of dry bean cultivars were equivalent for planting dates. The mid-May planted dry bean cultivars will result in higher seed yield and quality compared to the conventional late May planting in years with an early fall frost. Key words: Dry bean, seeding date, low temperature, emergence, maturity