Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Reddy, K. Raja

Committee Member

Wallace, Teddy P.

Committee Member

Baldwin, Brian S.

Committee Member

Paz, Joel O.

Committee Member

Reddy, Vangimalla R.

Date of Degree

12-14-2013

Document Type

Dissertation - Open Access

Major

Agronomy

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Abiotic stresses cause extensive losses to agriculture production worldwide. Cotton (Gossypium hirsutum L.) is an important fiber crop grown widely in subtropical region where temperature, water and nutrients are the common factors limiting crop production. Such losses could be more severe in the future climate as intensity and frequency of those stresses are projected to increase. The overall goal of this study was to evaluate effects of abiotic stresses on cotton reproductive performance and develop functional algorithms for fiber properties in response to different stress factors. Three experiments were conducted to evaluate the effects of temperature, water, and nitrogen in naturally-lit growth chambers. Influence of potassium nutrition was conducted in outdoor pot culture facility. In all experiments, upland cotton cultivar TM-1, a genetic standard, was used by imposing treatments at flowering. In all experiments, growth and photosynthesis measurements were recorded frequently during the treatment period. Biomass of various plant- and boll-components determined at harvest when 80% bolls were opened. Boll developmental period was tracked by daily tagging of flowers and open bolls. Bolls were grouped on the basis of onset of anthesis and lint samples were pooled together for fiber analysis. Fiber quality was assessed using High Volume Instrumentation and Advanced Fiber Information System. Total plant biomass, boll weights, and numbers significantly declined for plants grown under low and high temperature, severe water stress and nitrogen and potassium deficient conditions compared to optimum conditions for the respective stresses. Gas exchange processes were severely affected by moisture, nitrogen, and potassium deficient conditions. Time required from flower to open boll was mostly affected by growing temperature but not modified by other stresses. Fiber micronaire was most the responsive to changes in temperature, followed by strength, length and uniformity. Water limiting conditions and nitrogen defficiency severely affected strength and micronaire, whereas potassium deficiency had significant effect on fiber micronaire. This study was used to develop functional algorithms between abiotic stresses and fiber properties, once integrated into the crop simulation model. The improved crop model will be useful assist producers in optimizing planting dates, scheduling irrigation and fertigation to improve and fiber quality.

URI

https://hdl.handle.net/11668/18889

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