Fruiting in Cotton as Affected by Controlled Boll Set¹

Abstract

Environmental stress and boll load have both been suggested as responsible for the fruiting cessation (cut out) that occurs in cotton (Gossypium hirsutum L.) in mid‐summer in the hot, desert southwestern USA. This study was conducted to examine the influence of boll load on the flowering hiatus. Two cultivars differing in growth habit were planted in the field on an Avondale clay loam soil, a member of the fine, loamy, mixed Hyperthermic Torrifluventic Haplustolls. ‘Deltapine Smooth Leaf’ (DpSL) has a more determinate growth habit than ‘Acala 44–10’ (A‐44). Fruiting was limited during a 90‐day period within each year. Flowers in excess of one flower per plant per time interval, ranging from 2 to 5 days, were removed. Flowers left on plants were tagged and used to calculate boll retention curves. Limiting the number of flowers retained increased total flower production with DpSL more responsive than A‐44. Defloration resulted in cycling of the flower production curve which appeared to be related to relief of moisture stress either from irrigation or rain. Defloration increased both total and percent boll retention during the normal period of cessation of new vegetative and flowering growth with DpSL being more responsive than A‐44. We conclude that boll load exerts a large influence on fruiting behavior of cotton and is the major controlling factor of the cut out period in the cultivars tested.

High Night Temperatures During the Floral Bud Stage Increase the Abscission of Reproductive Structures in Cotton

“…A smaller plant fruit load corresponds to less internal competition for available resources and, hence, a greater flower setting (Patterson et al. ). Observations conducted for 7 years demonstrated a correlation between the minimum temperatures (NTs) and the number of bolls set on the plant (Fisher ).…”

“…In addition, the percentage of plants with bolls was only 20 % for those plants that grew under HNTs in the floral bud stage against 54 % and 55 % for those subjected to stress in the flowering stage and the control treatment, respectively. A smaller plant fruit load corresponds to less internal competition for available resources and, hence, a greater flower setting (Patterson et al 1978). Observations conducted for 7 years demonstrated a correlation between the minimum temperatures (NTs) and the number of bolls set on the plant (Fisher 1973).…”

Effects of early-fruit removal on endogenous cytokinins and abscisic acid in relation to leaf senescence in cotton

“…Compensation for early fruit removal in cotton has been of great interest to both agronomists and entomologists, as it will not only help in establishing the recovery potential, but also provide a good experimental condition to study association between source and sink, as well as vegetative and reproductive growth (Dong et al 2008b;Zhang et al 2008). Numerous fruit removal studies have shown that reproductive sink removal enhances vegetative growth and development (Patterson et al 1978;Kennedy et al 1986;Ungar et al 1987;Jones et al 1996). Loss of early fruiting forms has also been shown to increase root growth (Sadras 1996;Dumka et al 2004), alter spatial yield distribution (Bednarz and Roberts 2001), and improve Cry1AC expression of transgenic Bacillus thuringiensis Berliner (Bt) cotton (Zhang et al 2008).…”

Pamukta Tarak ve Çiçek Uzaklaştırmanın Etkisi : III. Çiçeklenme ve Silkme Düzeni

“…Guinn (1985) reported that flowers or bolls removal at first node has increased boll retention at second node. Patterson et al (1978) also, reported that at an early stage flowers removal has increased flowering and fruiting.…”