Utilizing phenotypic traits to predict seedling field vigor in a cotton breeding program

Successful field production of cotton requires rapid seedling emergence and robust vigor. A cultivar with these characteristics can be planted earlier in the season, allowing time for the plant to grow, mature, and maximize yield. Breeding programs seek ways to measure seedling vigor. The purpose of this research was to identify a method to measure vigor as well as determine seed characteristics that impact seedling vigor.
In this study, seedling vigor was tested in a germination chamber, followed by agronomic tests of seedling vigor. In the field seedling vigor was measured using the normalized difference vegetative index (NDVI) from multiple days after planting (DAP) on eight cultivars: DP 1646B2XF, FM 1911GLT, FM 1888GL, FM 1830GLT, FM 2322GL, FM 2574 GLT, ST 4946GLB2, and FM 1320GL. In addition, % oil content, grams per seed, seed length, seed width, bushel weight, seeds per bushel, warm germination, cool germination, and 4-day warm germination were used to identify seed characteristics that improve seedling vigor. ST 4946GLB2 and FM 1911GLT were found to have the highest seedling vigor, with oil content, germination chamber cool germination rating, and seed width being most linked to seedling vigor. In both years, vigor assessments 22-25 days after planting identified cultivar differences in seedling vigor. These findings suggest that selection for large seeds with high oil content, can be of value for germination, but that oil content is also an important selection criterion. In addition, in the absence of weed pressure, seedling vigor can be identified on a large scale using traditional remote sensing methods, such as NDVI.