Modern transgenic cotton (Gossypium hirsutum L.) cultivars with herbicide resistance have rejuvenated an interest in ultra-narrow row cotton production, primarily because of the reduction of weed control problems encountered in the past with ultra-narrow row systems. While the primary goal of ultra-narrow row cotton is to reduce production costs, an agronomic and physiological evaluation of this cropping system is also needed. The objectives of this study were to determine the feasibility of using modern transgenic cotton cultivars in ultra-narrow rows (<38 cm) for cotton production in the Mississippi Delta and to assess the effect of these various systems on cotton growth, lint yield, and fiber quality. Plant height and number of sympodia, total nodes, and total bolls per plant were reduced in cotton grown in ultra-narrow row spacings. In most cases, cotton grown in ultra-narrow rows had lint yields equal to or higher than those attained in the 101-cm spacing. In 2 of 3 yr, row spacing and cultivar interacted to significantly affect mean lint yield. In ultra-narrow rows, glyphosate-resistant transgenic cultivars produced yields equal to or better than conventional cultivars in 2 of 3 yr. Okra-leaf cultivars in narrow row cotton production did not improve lint yield. No conclusions could be made regarding the impact of plant stature on lint yield. Row spacing had little impact on fiber quality. Ultra-narrow row cotton appeared to be a viable agronomic cotton production practice for the Mississippi Delta compared with conventionally-grown cotton based upon lint yield and fiber quality.
