Phenotypic predictors for breeding drought tolerance in juvenile sugar beet.
Prior to establishment, juvenile sugar beets are highly sensitive to environmental stress such as drought. We evaluated populations of six breeding lines for tolerance to drought stress in the greenhouse over 3 weeks. Plants were phenotyped for photosystem I and II activity, leaf temperature and humidity, greenness, plant height, wilting, and root weight for the duration of the experiment to identify predictors associated with improved stress response. Differences were observed within and among beet lines with most beets showing a significant reduction in photosystem activity, GSW, and root weight during drought stress, and a significant increase in wilting. However, the extent of the stress response varied greatly among and within lines.