Semester of Graduation

Spring 2020

Degree

Master of Science (MS)

Department

Plant, Environmental, and Soil Sciences

Document Type

Thesis

Abstract

The importance of leaf area to corn for grain production beginning at silking is well documented. However, being able to predict yield loss due to defoliators such as foliar plant diseases and insects that progressively increase in defoliation over time has been difficult to quantify. To address this issue, a leaf removal study was conducted at the Dean Lee Research and Extension Center located near Alexandria, Louisiana in 2017 and 2018. Two hybrids, differing in relative maturity were evaluated in this study. An early maturing hybrid (108 days in 2017 and 107 days in 2018) and a later maturing hybrid (118 days) were used. Leaves were removed at one or more of the following corn growth stages: R1 (silking), R2 (blister), R3 (milk), and R5 (dent). All of the lower leaves (leaves below the ear leaf) were removed at the four different reproductive growth stages with the exception of the untreated check. Other treatments included continued removal of the upper leaf area at subsequent growth stages resulting in defoliation ranging from 50 and 78%.

Both hybrids responded similarly to yield loss from the defoliation treatments during both years of this study. Lower leaves are important to yield at the silking, blister, and milk stages of reproductive development. Yields were reduced even more when the upper leaves were incrementally removed beginning at these stages. Even at the dent stage, yields were reduced by over 5% when lower leaves were removed and over 10% when upper leaves were removed. Test weight and dry seed weight were also negatively influenced by defoliation, although the late hybrid was influenced less than the early. The objective of this study was to determine the effect of leaf loss at different reproductive stages of development on yield.

Committee Chair

Myers, Gerald

DOI

10.31390/gradschool_theses.5119

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