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Supplemental Boron, Boll Retention Percentage, Ovary Carbohydrates, and Lint Yield in Modern Cotton Genotypes
Author(s) -
Heitholt James J.
Publication year - 1994
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1994.00021962008600030007x
Subject(s) - loam , lint , fiber crop , leaf blade , malvaceae , agronomy , biology , gossypium hirsutum , horticulture , soil water , ecology
Cotton ( Gossypium hirsutum L.) is sometimes grown on soils with low B concentration. However, most of the literature regarding the effects of supplemental B on cotton was obtained from obsolete, low‐yielding genotypes rather than modern, high‐yielding genotypes. Therefore, the objective of this study was to determine the effects of soil‐ and foliarapplied B on leaf blade B concentration, boll retention, and lint yield of modern cotton genotypes. In 1991, three genotypes (DES 119, DES 24‐8 ne normal leaf, and DES 24‐8 ne okra leaf) and in 1992, two genotypes (Deltapine 20 and Deltapine 5415) of cotton were grown in the field on a Beulah fine sandy loam (coarse‐loamy, mixed, thermic Typic Dystrochrepts) having 0.11 mg kg −1 hot water extractable B concentration. Treatments included preplant soil and foliar (first flower to end of bloom) B (78% Na 2 B 8 O 13 ·4H 2 O, 20% Na 2 B 4 O 7 ·5H 2 O) applications for seasonal totals of 0, 0.89, or 1.78 (1992 only) kg B ha −1 . The lowest rate of foliar‐applied B increased leaf blade B concentration from 25 to 70 mg kg −1 in 1991 and from 54 to 108 mg kg −1 in 1992. In 1992, the highest rate of foliar B applications resulted in a leaf blade concentration of 154 mg B kg −1 . Soil‐applied B did not alter leaf blade B concentration in 1991, but slightly increased leaf blade B concentration in 1992 from 54 to 71 mg kg −1 . Soil B concentrations were higher during the midseason than the preplant period, suggesting that preplant soil B analysis may not accurately foreshadow soil B supply during the season. Soil B or foliar B applications did not affect boll retention percentage, flower number, or lint yield in either year. Supplemental B did not affect boll distribution in 1991, but in 1992, foliar B applications increased the percentage of fruit on monopodial branches. In both years, supplemental B did not greatly affect fiber properties with the exception that supplemental B increased fiber micronaire reading of Deltapine 20 in 1992. The results suggest that modern cultivars may not always need supplemental B when soil B concentration is moderately low.