EFFECTIVE FLOWERING TIME VARIATIONS IN UPLAND COTTON (GOSSYPIUM HIRSUTUM) AT DIFFERENT PLANTING DATES AND STAND DENSITIES IN BENIN

Abstract

Effective flowering time in Gossypium hirsutum cotton plants was studied with the aim of enhancing decision making on the best varieties to plant according to the planting date under rainfed cropping conditions. Trials were conducted at two sites in a cotton-growing area of Benin in 2002 and 2003. A split-split plot design with three replicates was used to compare 10 cotton varieties, with different growth cycle lengths and morphology, at three stand densities (42 000, 125 000, 167 000 plants ha −1 ) and two planting dates (standard planting in June and late planting). The flowering period was characterized by the mean first flower opening date (FF), which is an indicator of flowering earliness, and by the opening date of the last flower giving rise to a first-position boll on fruiting branches (LFP1). Effective flowering time (EFT) was calculated as the difference between LFP1 and FF. EFTs differed markedly in the 10 cotton varieties tested and this parameter could not be predicted on the basis of flowering earliness. Late planting and high planting rates delayed first-flower opening, accelerated last-boll development and reduced the effective flowering time. This latter factor should be taken into account in cotton breeding programmes so that varieties adapted to local rainfall constraints can be recommended to growers while also enhancing crop management sequences.

Breeding New Cotton Varieties to Fit the Diversity of Cropping Conditions in Africa: Effect of Plant Architecture, Earliness and Effective Flowering Time on Late-Planted Cotton Productivity

“…This deficit was offset under late planting-high stand density conditions, but yields, except for Mar 88-214, still did not surpass those of later varieties with less determinate growth, thus confirming previous results obtained by Crawley et al (2004), Galanopoulou-Sendouka et al (1980) and Porter et al (1995). In late planting conditions, the effective flowering time is uniformly shorter for all ideotypes (Sekloka et al, 2007b) and early varieties do not fully benefit from their higher yielding capacity. In North Carolina, May and Bridges (1995) also found no significant genotype by late or early cropping system interaction for yield, but their results were obtained with a narrow genetic pool of lines already adapted to intensive agriculture (irrigation, mechanical harvest).…”

“…(1995). In late planting conditions, the effective flowering time is uniformly shorter for all ideotypes (Sekloka et al ., 2007b) and early varieties do not fully benefit from their higher yielding capacity. In North Carolina, May and Bridges (1995) also found no significant genotype by late or early cropping system interaction for yield, but their results were obtained with a narrow genetic pool of lines already adapted to intensive agriculture (irrigation, mechanical harvest).…”

“…plants in groups, under early planting and low stand density. The EFT indicator distinguished between different late varieties and different early varieties (Sekloka et al ., 2007b). In H 279-1, a high EFT value indicated that the effective flowering cycle of late varieties could be extended despite late flowering onset.…”

Influence of Ultranarrow Row and Conventional Row Cotton on the Last Effective Boll Population

“…Moreover, Jost and Cothren (2000) reported earlier maturity in UNRC than in CONC, which was thought to result from CONC producing more main stem nodes than UNRC. Sekloka et al (2007) also reported that effective flowering time can be effected by varieties with relatively longer growth cycles.…”

“…Concerning effective flowering date, the UNRC produced flowers earlier at NAWF 1, 2, 3, 4, and 5 (84, 80, 75, 72, and 70 d after planting) compared with the CONC (88, 85, 80, 76, and 72 d). Sekloka et al (2007) also indicated that higher plant densities slightly reduce effective flowering dates. Moreover, Jost and Cothren (2000) reported earlier maturity in UNRC than in CONC, which was thought to result from CONC producing more main stem nodes than UNRC.…”