Seed Density Classification Influences Germination and Seedling Growth of Cotton1

Abstract

Among cotton (Gossypium hirsutum L.) seeds with densities less than 1.00 g cm−3, germination performance has been shown to be proportional to the seed density. Since cotton seeds produced in the mid‐South usually attain densities higher than 1.00 g cm−3, we evaluated the germination performance of seeds with densities ranging from ≤ 1.00 to 1.10 g cm−3 to determine if the proportionality between seed density and germination performance might extend beyond 1.00 g cm−3. In laboratory, greenhouse, and growth chamber studies, maximum germination and sustained seedling growth were produced by seeds with initial densities of 1.04 and 1.06 g cm−3. The quantity of oll in the seeds was increased with seed density, but both seed weight and seed volume were decreased in the higher density seed classes. The ratio between seed oil and seed protein contents increased through a seed density of 1.06 g cm−3, then decreased slightly. Germination and seedling growth exhibited the same response to density classification as did the oil:proteln ratio. The principal deficiency of the high density cotton seeds appeared to be the low weights of cotyledonary reserves available for mobilization during germination. Selection of cotton seeds on the basis of density should therefore be done so that the small volume, light weight, but high density seeds are eliminated with the low density seeds.