Influence of Flower Removal on Cotton Growth and Boll Develop

N.A. Jones, R. Wells, and D.S. Guthrie


 
ABSTRACT

Flower removal treatments were imposed on two cultivars (Deltapine 50 and 90) to determine the effect of varying boll competition levels on yield and fiber quality. In 1991, the flower removal treatments consisted of: a) no removal (control), b) 1st week flowers, c) 1st and 2nd week flowers, d) 1st-3rd week flowers, e) 3rd and 4th week flowers, f) 4th week and later, g) 5th week and later, and h) all flowers. In 1992, treatments b, e and h were excluded and a 6th week and later removal was added. Total yield, yield components, and fiber quality were monitored over four stratified harvests in 1991 and three in 1992. Both years exhibited similar patterns concerning cumulative fiber yields. Early removals (3rd week and before) had no significant effect on total fiber yield despite reductions during the early harvests, thus indicating compensation for early losses. This response occurred despite a cooler and wetter pre-anthesis period in 1992 compared to 1991. Later removals significantly reduced fiber yields, with reductions during 1991 of 21, 30 and 14% for the 3rd and 4th week, 4th week and later, and 5th week and later treatments, respectively. In 1992, yield reductions of 43, 33, and 24% were observed for the 4th, 5th, and 6th week & later treatments, respectively. Boll weights were related to the amount of competition among developing bolls, with the largest bolls (>5.0 g boll-1) arising from treatments which had the largest negative effect on yield. In 1991, both micronaire and fiber strength displayed curvilinear relationships with boll weight (R2=O.62 and 0.30, respectively) and thus underscores the relationship of boll competition with quality. The data indicate that late flower losses are the most injurious to yield and that early losses can be tolerated if the season allows compensatory growth.



Reprinted from 1993 Proceedings Beltwide Cotton Conferences pg. 1271
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998