Eight edamame [Glycine max (L.) Merrill] cultivars were evaluated in the field in 2002, 2003, and 2004 to determine their suitability for growing in central Pennsylvania. Each cultivar was direct seeded and data collected included plant populations (percentage of stand) and marketable yields. Plant populations ranged from less than 1% to 81% and, with one exception in 2002, were below 80%. Eighty percent plant populations or higher are considered optimal. Based on sub-optimal plant populations, none of the edamame cultivars evaluated in the field were determined to be suitable for direct seeding in central Pennsylvania. The effect of temperature on seedling emergence, and therefore, plant populations was then studied. Four of the edamame cultivars used in the field trial were evaluated in growth chambers programmed with varying day/night temperature regimes. Seedling emergence varied by cultivar and was generally below 80% with two exceptions. When grown in a 21.1 °C day/15.6 °C night temperature regime, `Butterbeans' and `Early Hakucho' exceeded 80% seedling emergence. These methods could be used to produce transplants; however, the economic feasibility of doing so should first be evaluated. In the field trial, conclusions on marketable yields were unattainable because soybean plants are known to compensate in yield for plants missing in sub-optimal plant populations. Plant compensation and sub-optimal plant populations rendered yield comparisons between cultivars questionable. The issue of sub-optimal seedling emergence and plant population needs to be studied further before suitability of growing these edamame cultivars in central Pennsylvania can be determined.
Adaptive radiation of photosynthetic physiology in the Hawaiian lobeliads: light regimes, static light responses, and whole-plant compensation points
