Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Bond, Jason A.

Committee Member

Golden, Bobby R.

Committee Member

Allen, Tom W.

Committee Member

Carey, Victor F.

Committee Member

Dodds, Darrin M.

Date of Degree

8-9-2022

Document Type

Graduate Thesis - Campus Access Only

Major

Agronomy

Degree Name

Master of Science (M.S.)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Optimal plant populations are critical in achieving high rice yields. The purpose of this research was to investigate yield penalties associated with inadequate, non-uniform plant populations for modern rice cultivars. Research was conducted at the Delta Research and Extension Center in Stoneville, MS, in 2019, 2020 and 2021. In one study, inbred, herbicide-resistant ‘CL153’ was drill-seeded at 73-18 kg ha-1 after being mixed with inbred, herbicide-susceptible ‘Rex’ at 0-55 kg ha-1. Likewise, hybrid, herbicide-resistant cultivar ‘CL XL7521’ was seeded at 29-8 kg ha-1 mixed with hybrid, herbicide-susceptible ‘XP753’ at 0-21 kg ha-1. At the two- to three- leaf growth stage, imazamox was applied to eliminate ‘Rex’ and ‘XP753’ in their respective studies to achieve the target plant population (TPP). Results indicate that when plant populations are reduced up to 30% in both inbred and hybrid cultivars, grain yields should be comparable if not greater than an adequate, uniform plant population.

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