Competition Between Adjacent Fruiting Forms in Cotton1
- T. A. Kerby and
- D. R. Buxton2
Cotton plants (Gossypium hirsutum L.) produce more fruiting forms that can be supplied assimilates, and competition and abortion occurs. The relationship is accentuated with narrow-row, high population culture. This study was conducted to determine the extent that fruiting forms compete and influence abscission of adjacent fruiting forms. The study was also designed to determine if plant leaf type or plant density altered the effects of competition.
Normal, Okra, and Super Okra-leaf cotton plants were grown in rows 51 cm apart in irrigated basins at 11.2 and 18.5, and 10.0 and 20.0 plants/m2 in 1973 and 1974, respectively. The soil type was a coarse-loamy, thermic, Typic Torrifluvent (a member of the Gila series). Fruiting positions reaching anthesis were tagged daily. Fruiting positions on sympodial branches were identified as L1 for the first position and L2 for the second position.
Averaged over genotypes, plant densities, and years, 25% of the positions at L2 retained bolls when L1 aborted as a square compared to only 10 and 11% when L1 aborted as a young boll or retained a boll until maturity, respectively. Averaged over plant densities and years, when bolls were retained at L1, 60% of the positions at L2 aborted as young bolls for Super Okra-leaf plants compared to only 34% for normal-leaf plants. However, normal-leaf plants aborted 52% of the positions at L2 as squares compared to only 32% for Super Okra-leaf plants. Averaged over genotypes and years, when L1 retained a boll, high plant densities aborted 45% of the positions at L2 as squares compared to 35% for low plant densities.
Under narrow-row, high-population culture it was apparent that adjacent fruiting forms competed for available assimilates, and that the potential for developing more than one boll per sympodial branch was low. The use of cultivars which produce long sympodial branches appears to be inefficient under this system.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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