Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Rangappa, Raju Bheemanahalli

Committee Member

Reddy, K. Raja

Committee Member

Harkess, Richard

Committee Member

Shanmugam, Shankar Ganapathi

Committee Member

Barickman, T. Casey

Date of Degree

8-7-2025

Original embargo terms

Visible MSU Only 1 year

Document Type

Graduate Thesis - Campus Access Only

Major

Plant and Soil Sciences (Agronomy)

Degree Name

Master of Science (M.S.)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Cowpea (Vigna unguiculata (L.) Walp.) is an important leguminous crop. Exposure to drought can lead to significant reductions in yield and quality. Designing strategies to mitigate the effects of drought requires a comprehensive understanding of how trait variability influences resilience at various crop growth stages. Three experiments were conducted to assess the response and resilience of various cowpea genotypes under control (100% irrigation) and drought (50% irrigation of control for 14 days) conditions during the vegetative (nodulation initiation - V2, and peak branching - V4) and reproductive (flowering - R1, and seed fill - R4) stages. The short-term drought impacted physiology and biomass, resulting in a significant reduction in 46% yield during R1, followed by R4 (35%), V2 (33%), and V4 (27%). Phenotyping of diverse genotypes at V2 revealed that deep-rooted genotypes exhibited greater drought tolerance compared to shallow-rooted ones. However, drought at R1 severely impacted the genetic potential of traits, leading to reduced gas exchange, a 4.6°C increase in canopy temperature, and a 47% yield decrease due to poor seed set compared to the control. The reproductive stage is more sensitive to drought than the vegetative stages. Deep-rooted genotypes maintained a cooler canopy during different growth stages, making this combination of traits valuable for enhancing yield potential in drought conditions.

Sponsorship (Optional)

Mississippi Agricultural and Forestry Experiment Station, Special Research Initiative (MAFES-SRI)

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