Response of short and full season cotton cultivars to mepiquat chloride /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1985.
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| Subjects: | |
| Online Access: | Link to ProQuest copy Link to OAKTrust copy |
| Abstract: | The effects of mepiquat chloride (1,1 dimethyl piperidinium chloride), applied at three different stages of crop development, were evaluated on cotton cultivars of differing growth habit and determinacy (TAMCOT CAMD-E and Stoneville 213) to determine effects on phenological and morphological characters with respect to maturity and earliness and their interrelationships with yield and fiber properties. Field evaluation of plants grown from seeds of mepiquat chloride (MC) treated plants was conducted the following year for residual effects of the compound. MC treatment reduced number of sympodia in Stoneville 213, and in both cultivars, significantly reduced lateral and vertical internode distances, plant height, and canopy width. Degree of reductions in morphological traits depended upon time of MC application. Light penetration through leaf canopy was increased in Stoneville 213 but reduced in TAMCOT CAMD-E, with early and recommended MC treatments. In both cultivars, MC treatment did not affect bloom production nor rate of blooming, but significantly lengthened horizontal flowering intervals. MC treatment significantly reduced boll maturation period based on accumulated degree-days. Early and recommended MC-treated Stoneville 213 had shorter mean maturity date, higher maturity rate index and increased percentage harvest in first and second picks. Only percentage harvest in first pick was improved in TAMCOT CAMD-E. Improvements in product-quantity indices of early maturity were associated with changes in morphological variables. In both cultivars, MC treatment reduced vegetative dry weight, but differences in boll and total plant dry weights and number of bolls were not affected significantly. MC treatment showed increases of seedcotton and lint yields in Stoneville 213 but not in TAMCOT CAMD-E, although differences were not significant. Yield increase in Stoneville 213 was associated with morphological modifications, reduced vegetative growth, improved light penetration into leaf canopy, and increased production rate index. Fiber length and length uniformity were increased in MC-treated Stoneville 213 but not in TAMCOT CAMD-E. In both cultivars, seeds from MC-treated plants had significantly less electrolytic leakage but did not affect germination percentage. Field evaluation of plants grown from seeds of MC-treated plants also showed no residual effects of the compound. Results suggest that full season types are more flexible than short season types in their response to MC treatment and period of application may not be generally specified for all types of cotton. |
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| Item Description: | "Major subject: Plant Breeding." Typescript (photocopy). Vita. |
| Physical Description: | xi, 138 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 130-136). |