Effect of Anthracnose Leaf Blight on Stalk Rind Strength and Yield in F₁ Single Crosses in Maize. M. S. Zuber, Professor of Agronomy, University of Missouri, Columbia 65211. T. C. Ainsworth, Plant Breeder, Ainsworth Seed Company, Mason City, IL 62664; M. H. Blanco, Plant Pathologist, O’s Gold Seed Company, Farmer City, IL 61842; and L. L. Darrah, Research Geneticist, AR, SEA, USDA, Columbia. Plant Dis. 65:719-722. Accepted for publication 23 December 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-719.

Fifteen F₁ crosses among six maize (Zea mays) inbred lines were planted in a replicated split-plot design. Plants in one row of the split plot were inoculated with conidia of Colletotrichum graminicola at the six- to eight-leaf stage of development. Control plants in the second row of the split plot were not inoculated. The 15 inoculated F₁ crosses yielded significantly less grain and had more stalk lodging, lower rind puncture values, higher leaf blight ratings, and less grain moisture. Some inbred lines as parents of hybrids contributed high levels of resistance. When inoculated and uninoculated treatments were compared, hybrids from these lines had smaller differences in grain yield than did other hybrids. Several F₁ crosses were highly resistant to the leaf blight phase but had large yield reductions and high percentages of stalk lodging. This result suggests that resistance to leaf blight is affected by a different genetic mechanism than that affecting stalk quality. Rind puncture was a useful technique for identifying genotypes with resistance to the stalk rot phase of the disease, as reflected by differences in rind strength.

Keyword(s): rind component.