Cotton is known for having poor seedling vigor relative to other crop species, and it is well-known that vigorous early season growth is a desirable trait to minimize the risks of poor stand establishment.
The cotton physiology lab has shown that
- seedling vigor is associated with seed physical and chemical characteristics (seed mass and oil + protein kcal content),
- larger seeded cultivars tend to exhibit more vigorous seedling growth when sown on planting dates associated with suboptimal temperature conditions, but cultivar differences are less apparent under warmer planting dates,
- cultivar and planting date-induced variation in early season crop growth rates and individual seedling growth are more closely associated with rapid early leaf area development than photosynthetic activity of the canopy.
Because growth temperature can also strongly influence seedling vigor, the cotton physiology lab commonly assesses for cultivar differences in seedling vigor under a wide range of temperature conditions. Importantly, the cotton physiology lab has identified novel chlorophyll fluorescence measurements that are strongly indicative of temperature-induced variation in seedling vigor. This is important because chlorophyll fluorescence measurements can rapidly assess a large number of samples in a much shorter period of time than traditional growth assessments.