Cotton Flowering and Boll Retention in Different Planting Configurations and Leaf Shapes

Abstract

AbstractNarrow rows have the potential to increase boll numbers and lint yield of cotton (Gossypium hirsutum L.) compared with conventional row spacing. To optimize production in this system, it is important to know whether narrow‐row‐induced boll number increases are a result of increased seasonal flowering or increased boll retention. The objective of this study was to determine flower production (no. m−2), boll retention [(bolls/flowers) ✕ 1001, main stem node number, and yield as affected by row spacing and plant density. Field experiments were conducted in 1991 and 1992 on a Bosket fine sandy loam in narrow (51 or 76 cm) and wide rows (102 cm) using the normal‐ and okra‐leaf isolines of DES 24‐8 ne cotton. Plant densities were 5, 10, 15, and 20 plants m−2 in 1991 and 2, 3, 5, 10, and 15 plants m−2 in 1992. Averaged across leaf types and plant densities, 51‐cm rows increased the number of flowers by 12% and yield by 4% compared with 102‐cm rows in 1991. Boll retention was 40% for both row spacings. In 1992, averaged across leaf types and plant densities, 76‐cm rows increased the number of flowers by 21% and yield by 6% compared with 102‐cm rows. Boll retention was actually higher in 102‐cm rows (42%) than 76‐cm rows (36%). In general, plant density and the number of main stem nodes had little effect on flower numbers or boll retention. High plant densities tended to reduce the number of main stem nodes per plant. Averaged across row spacings, plant densities, and years, boll retention for normal‐leaf was higher than for okra‐leaf (50 vs. 29%). Results indicate that increased flower production rather than increased boll retention was responsible for the small narrow‐row yield increase.