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.

Associations between first true leaf physiology and seedling vigor in cotton under different field conditions

“…Abdul-Baki and Anderson (1973) suggested the use of a seedling vigor index (SVI) calculated from root length and hypocotyl length. Fresh weight, dry weight, emergence time, plant height, and node development of seedlings, among other measures, are commonly used to determine seedling vigor (Ferguson & Turner, 1971;Kreig & Bartee, 1975;Leffler & Williams, 1983;Snider et al, 2014Snider et al, , 2016. Bourland (1992) suggested that "rapid true leaf differentiation and nodal development, well developed seedling roots and low seedling disease incidence" should be the defining criteria for seedling vigor in cotton.…”

Morphological Traits Underlying Differences in Early Vigor among Four Cotton Genotypes

“…Information on the mechanisms determining early vigor in cotton is limited. To date, studies have primarily focused on various seed characteristics, including seed size (Snider et al, 2014), seed filling (Ferguson and Turner, 1971), seed density (Krieg and Bartee, 1975;Leffler and Williams, 1983), and seed chemical composition (Turley and Chapman, 2010;Snider et al, 2014Snider et al, , 2016. Growing environment and genotype effects were significant for many of the measured traits.…”

“…However, despite the importance of seedling vigor, characterization of early growth and mechanisms associated with vigorous early growth have received only limited attention in cotton. To date, studies have primarily focused on various seed characteristics, including seed size (Snider et al, 2014), seed filling (Ferguson and Turner, 1971), seed density (Krieg and Bartee, 1975;Leffler and Williams, 1983), and seed chemical composition (Turley and Chapman, 2010;Snider et al, 2014Snider et al, , 2016. Other studies have provided some information on photosynthesis (Cook and El-Zik, 1992), development of an early true leaf (Ortiz and Bourland, 1999), and biomass and leaf area production (Liu et al, 2015(Liu et al, , 2019 during early growth based on limited samplings, but these studies lack detailed growth analyses.…”

Amorçage et séparation des graines d'épinette noire (Picea mariana (Mill.) B.S.P.) :

“…Les graines d'épinette noire des lots utilisés ont plutôt montré qu'il existe une densité où la germination est optimale et qu'une réduction de germination se produit dans les catégories de densité plus élevée. Chez certaines espèces végétales, il n'existe pas de relation entre la masse volumique et la capacité germinative des graines (Hill etal., 1989;Baalbaki et Copeland, 1997) et l'existence d'une densité optimale est rapportée dans le cas des semences de coton {Gossypium hirsutum L.) (Leffler et Williams, 1983).…”