Seed Size and Ginning Efficiency in Upland Cotton (Gossypium hirsutum L.).

In 2015 and 2016 nine diverse upland cotton cultivars and germplasm lines were planted at two locations in Stoneville, MS. Two of the cultivars (Ark 9317-26 and DP 555 BG/RR were classified as ‘small’ because they have seed index (SI) of < 10 g. FM 832, FM 966, and MD 15, had SI ranging from 10-12 g and were classified as having ‘intermediate’ seed size. TAM 182-34 ELS and three other breeding lines 201-2, 107-1, and 152-1 had ‘large’ seeds with SI of > 12 g. The materials were planted in three replications each at two sites in both years at Stoneville. Data were collected on ginning energy requirement (Wh kg^-1 lint), ginning rate (g lint s^-1), fibers per seed, seed surface area, fuzz percent, gin turnout, HVI and AFIS quality parameters. The objectives of the test were to see the effects and interactions of seed size with the above parameters. Statistical analyses of all properties associated with the genotypes were performed using Proc GLM. Simple Pearson’s correlation tests and regression analyses were conducted to test the relationship between traits. Significant differences between the three different seed sizes were observed among all parameters. Small and intermediate seeded genotypes had higher ginning rate than large seeded genotypes. Large seeded genotypes required higher energy to gin than the intermediate and small genotypes. Seed index was positively but not significantly correlated with ginning rate. But the relationships with ginning energy, seed surface area and fuzz percent were positive and significant. The relationships of seed index with lint yield and gin turnout were significant and negative. Fiber strength was the only quality trait positively and significantly correlated with seed index.