Identification of Tropical and Temperate Maize Populations Having Favorable Alleles for Disease Resistance

• Published in: Crop science Vol. 40; no. 4; pp. 948 - 954
• Main Authors: Kraja, Aldi, Dudley, John W., White, Donald G.
• Format: Journal Article
• Language: English
• Published: Madison Crop Science Society of America 01-07-2000; American Society of Agronomy
• Subjects: Agriculture; Agronomy. Soil science and plant productions; Biological and medical sciences; Bipolaris maydis; Breeding; Cercospora zeae-maydis; Corn; Corn belt; Crops; Disease; Disease resistance; Diseases and pests; Exserohilum turcicum; Fundamental and applied biological sciences. Psychology; Genetics; Genetics and breeding of economic plants; Helminthosporium carbonum; Hybrid corn; Pest resistance; Physiological aspects; Plant breeding; Plant genetics; Plant pathogens; Plants; Puccinia sorghi; Varietal selection. Specialized plant breeding, plant breeding aims; Zea mays; United States; Bipolaris zeicola; Monocotyledones; Zea mays; Plant pathogen; Tropical zone; Bipolaris maydis; Basidiomycetes; Temperate zone; Population genetics; Cereal crop; Fungi; Disease resistance; Exserohilum turcicum; Germplasm; Puccinia sorghi; Sensitivity resistance; Gramineae; Angiospermae; Genetic improvement; Spermatophyta; Fungi Imperfecti; Intraspecific comparison; Thallophyta
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2000.404948x

A possible use of nonelite germplasm is as a source of alleles for disease resistance. Our objective was to determine the value of tropical and temperate maize (Zea mays L.) germplasm accessions as sources of alleles to improve disease resistance of the Corn Belt hybrid FR1064 × LH185. A group of tropical populations and hybrids from the Germplasm Enhancement of Maize Project (GEM) crossed to either Mo17 or B73 (temperate inbreds), was studied. In addition, a group of temperate accessions was evaluated. Reaction to southern corn leaf blight (SCLB) [Bipolaris maydis (Nisikado & Miyake) Shoemaker = Helminthosporium maydis Nisikado & Miyake], northern corn leaf spot (NCLS) [Bipolaris zeicola (G. L. Stout) Shoemaker = Helminthosporium carbonum Ullstrup Races 2 and 3], gray leaf spot (GLS) (Cercospora zeae‐maydis Tehon & E.Y. Daniels), northern corn leaf blight (NCLB) [Exserohilum turcicum (Pass.) K. J. Leonard & E. G. Suggs = Helminthosporium turcicum Pass., Races 1, 1, 2, 23N and three unidentified races] and common rust (Puccinia sorghi Schwein) was studied using Dudley's method for identifying populations with favorable alleles. All accessions had favorable dominant alleles for resistance not present in FR1064 × LH185 for common rust, GLS, and SCLB. Four accessions had a number of favorable alleles for resistance not significantly different from the best accession for all five diseases. Crosses of the accessions containing Mo17 to FR1064 and LH185 were less susceptible to SCLB, NCLB, and rust than crosses of accessions containing B73. At least seven of the best 10 populations were tropical × Mo17 crosses for SCLB, NCLB, and rust when populations were ranked for presence of favorable alleles for resistance not present in either LH185 or FR1064. Net value statistics for tropical × B73 and tropical × Mo17 accessions differed in indicating whether backcrossing or selfing from the F1 is more desirable. Therefore, if tropical populations are crossed to Corn Belt inbreds to increase adaptation, comparisons among tropical populations should only be made when all populations being compared have been crossed to the same Corn Belt inbred.