Yield, Flowering, and Leaf Area Index of Okra-Leaf and Normal-Leaf Cotton Isolines

Cotton (Gossypium hirsutum L.) with alternative leaf morphologies, such as the cleft-shaped okra-leaf types, offers production advantages such as earlier maturity. However, okra-leaf types have not been commercially viable in the USA. The objectives of this study were to test okra-leaf types in genetic backgrounds varying in maturity and region of adaptation and to provide growth data that might explain yield differences. Four to seven pairs of selected cotton okra- and normal-leaf isolines (and check cultivars) were grown in the field in one 2-yr (Exp. A) and two 1-yr experiments (Exp. B and C) from 1994 to 1996 near Stoneville, MS, in row spacings of 76 and 102 cm. In Exp. A, average lint yields of okra-leaf isolines were greater overall than normal-leaf lines (847 vs. 749 kg ha⁻¹), but in Exp. C, the opposite was true (1020 kg ha⁻¹ for okra- vs. 1130 kg ha⁻¹ for normal-leaf types). No yield difference was found between leaf types in Exp. B. Yields of okra-leaf lines were either equal to or less than those of recently released high-yielding commercial types whose okra-leaf isolines are not yet available. Okra-leaf types were usually 1 to 4 d earlier in maturity than their normal-leaf counterparts, possibly contributing to their overall yield advantage in Exp. A. When only okra-leaf isolines were considered, Tamcot HQ95 ranked first or second highest for yield and was the earliest to mature in all three tests. In general, the row-spacing effect and interactions with row spacing were not significant. The results indicate that the okra-leaf trait should be considered for producing future cultivars. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the product or service, and the use of the name by USDA implies no approval of the product or service to the exclusion of others that may also be suitable.