Suboptimal seedbed temperatures in early spring limit common bean (Phaseolus vulgaris L.) seedling emergence. This field study evaluated emergence of cultivated and wild common bean when subjected to suboptimal seedbed temperature. One hundred and eighty common bean accessions and three control cultivars were planted on 3 May at Saskatoon, Sask., in 2000 and 2001. Percent emergence, cumulative thermal units to 50% anthesis and to 50% maturity, and seed yield were determined. The seedbed temperature during the 2 weeks after planting ranged between 1 and 18 °C in 2000, and 5 and 17 °C in 2001. At 20 days after planting, emergence in accession G8823 was significantly greater than the control cultivars in 2000. `CDC Nighthawk', a black bean control cultivar was comparable in emergence to G8823 at 30 days after planting. A similar trend was observed in 2001 with the exception that emergence was greater at 30, 40, and 50 days after planting due to a warmer seedbed. `CDC Nighthawk' was among the earliest to mature, although it required a significantly higher cumulative thermal unit to anthesis compared to most other accessions. G8823 could serve as a parent to develop elite bean cultivars with emergence at suboptimal seedbed temperatures.
Current address: Agriculture and Agri-Food Canada—Morden Research Station, 100-101 Route 100, Morden, Manitoba, R6M 1Y5. Corresponding author: e-mail: email@example.com