Vigor Components of Cotton.

Vigorous early season growth is a desirable characteristic across all crops and geographies, and this is especially true for cotton produced in the challenging environment on the Texas High Plains. After lint yield, seedling vigor is one of the most valued properties of cotton cultivars marketed in the region. To investigate aspects of vigor and their correlation with crop performance, an evaluation of 12 commercial cotton cultivars was conducted in New Deal, TX during 2016. Established seed properties linked to vigor, including seed size and oil content, as well as multiple plant growth and development measurements that are often used to rate vigor were analyzed. A relatively strong relationship was present between visual ratings of vigor (the typical method of vigor evaluation) and seed mass (R² = 0.6146) and oil content (R² = 0.6579). A similar relationship was observed with seed mass and oil content and measurements of leaf area and total dry weight per plant taken 21 days after planting (DAP). Differences between cultivars for leaf area and total dry weight per plant were observed at 21 DAP, following the patterns in seed mass and oil content. Despite a strong relationship between seed mass and seed oil content (R² = 0.7266), seed mass was substantially more reflective of leaf area (R² = 0.6021) and total dry weight per plant (R² = 0.5807) than seed oil content (R² = 0.4587 and 0.3926, respectively). These results suggest the more readily available parameter of seed mass (reflected by seed per pound on every seed bag) may be a more reliable reference for determining seedling vigor than seed oil content available through seed analysis. However, additional years of data are required, particularly given the environmental conditions present in 2016 offered minimal challenges to early season growth that would have favored more vigorous cultivars.