The Cotton Boll: The Relationship of Species and Genotype with Temporal Development of Boll Wall Thickness

Abstract

Cotton (Gossypium spp. L.) is a high‐value cash crop worldwide, and numerous pest insects can injure the developing cotton boll, thereby reducing yields and fiber quality. Thickness of the boll wall may be instrumental in deterring these seasonal pests, but the temporal development, or rate at which the boll wall thickens, is not known. The objective of this study was to determine boll wall thickness in four cotton species (G. arboreum L., G. barbadense L., G. herbaceum L., and G. hirsutum L.) and among selected entries within species at selected boll ages. Temporal boll wall thickness differed significantly between cotton species, as well as among entries within species. Overall, mean wall thickness was significantly affected by cotton species and boll age. When boll ages were pooled, G. barbadense possessed significantly higher mean wall thickness than G. arboreum, G. hirsutum, and G. herbaceum. When cotton species were pooled, maximum wall thickness was observed at 14 d after flowering, followed by 21 d after flowering, and these were significantly greater than at 3, 7, and 28 d after flowering. Within all species, temporal differences in wall thickness were observed between and among entries evaluated. These findings improve our understanding of boll wall development and provide a foundation for screening cotton germplasm to potentially select for increased wall thickness as a source of pest resistance.

The Cotton Boll: Temporal Susceptibility of the Boll Wall to Stylet Penetration by Hemipteran Pests

“…The reader is directed to Esquivel and Hinze (2019) for more detailed analyses of overall observed mean temporal wall measurements for all entries. The PROC MEANS statement (SAS Institute, 2016) was used to generate descriptive statistics and identify the minimum and maximum values (or range) of minimum observed thickness, as well as the means (and SD) of the observed minimum values for each entry and age combination within respective Gossypium species and entries.…”

“…Although previous work has addressed physiological properties (e.g., accumulation of heat units and "toughness" of the boll wall) as indicators to determine when cotton bolls are no longer susceptible to feeding or damage by stink bugs (Greene et al, 1999;Willrich et al, 2004), data are lacking regarding the relationship between temporal physical properties of the cotton boll wall (i.e., thickness) and hemipteran insect pest feeding behavior (i.e., stylet penetration potential). Esquivel and Hinze (2019) provide detailed analyses of the temporal thickness of the developing boll wall for multiple entries of four cotton species (i.e., Gossypium arboreum L., G. barbadense L., G. herbaceum L., and G. hirsutum). Esquivel and Hinze (2019) provide detailed analyses of the temporal thickness of the developing boll wall for multiple entries of four cotton species (i.e., Gossypium arboreum L., G. barbadense L., G. herbaceum L., and G. hirsutum).…”

“…Cotton bolls with thicker walls reportedly mitigate damage by boll-feeding insects (Singh et al, 1965), but it is currently unknown how temporal boll wall thickness affects stylet penetration by hemipteran pests of cotton. The objective of the current report is to parlay the findings of boll wall thickness and observations of Esquivel and Hinze (2019) to more clearly elucidate the relationship between the temporal development of the cotton boll wall and the time at which bolls initially become susceptible to breaching of the internal carpel wall by stylets of hemipteran pests. The objective of the current report is to parlay the findings of boll wall thickness and observations of Esquivel and Hinze (2019) to more clearly elucidate the relationship between the temporal development of the cotton boll wall and the time at which bolls initially become susceptible to breaching of the internal carpel wall by stylets of hemipteran pests.…”

“…Esquivel and Hinze (2019) provide detailed analyses of the temporal thickness of the developing boll wall for multiple entries of four cotton species (i.e., Gossypium arboreum L., G. barbadense L., G. herbaceum L., and G. hirsutum). Esquivel and Hinze (2019) surveyed 16 entries representing four cotton species to measure boll wall thickness in a broad range of genotypes (Table 1). Esquivel and Hinze (2019) surveyed 16 entries representing four cotton species to measure boll wall thickness in a broad range of genotypes (Table 1).…”

“…Esquivel and Hinze (2019) provide detailed analyses of the temporal thickness of the developing boll wall for multiple entries of four cotton species (i.e., Gossypium arboreum L., G. barbadense L., G. herbaceum L., and G. hirsutum). The objective of the current report is to parlay the findings of boll wall thickness and observations of Esquivel and Hinze (2019) to more clearly elucidate the relationship between the temporal development of the cotton boll wall and the time at which bolls initially become susceptible to breaching of the internal carpel wall by stylets of hemipteran pests. Esquivel and Hinze (2019) surveyed 16 entries representing four cotton species to measure boll wall thickness in a broad range of genotypes (Table 1).…”