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GENETIC AND CYTOGENETIC STUDIES ON INHERITANCE OF SUSCEPTIBILITY IN MAIZE (ZEA MAYS L.) TO CLAVIBACTER (CORYNEBACTERIUM) MICHIGANENSE SSP. NEBRASKENSE (PLANT DISEASE)
Abstract
Goss's wilt, caused by Clavibacter (=Corynebacterium) michiganense ssp. nebraskense (C. m. ssp. nebraskense), is a foliar and vascular disease of maize (Zea mays L.). This disease, first reported in central Nebraska in 1969, has since spread throughout a major portion of the northern Corn Belt. This research investigation was designed to add to the knowledge of the cytogenetic basis of susceptibility to this disease. Two sets of endosperm-marked interchange (chromosomal reciprocal translocation) stocks in the resistant inbred M14 were crossed onto the susceptible inbred A632. Testcross, F2, and F3 progenies were developed and seed of individual progenies were separated by endosperm markers and were planted in paired rows in randomized complete blocks in the field. Plants were inoculated with C. m. ssp. nebraskense and scored for disease reaction. Chi-square tests for association of endosperm type and disease reaction were performed to identify chromosome arms of inbred A632 with a gene(s) for susceptibility to C. m. ssp. nebraskense. Results indicated that several chromosome arms of inbred A632 contained genes that affected the susceptible response to C. m. ssp. nebraskense. Chromosome arms 4S, 7L, and 8L appeared to have genes with major effects on susceptibility whereas 1S, 1L, 2S, and 3L had genes with lesser effects. Genotype by environment interactions were common and disease reaction varied across disease-scoring dates for many progeny. A set of interchange stocks in the susceptible inbred A632 that transmitted duplicate-deficient segments of the chromosomes involved in the interchanges were crossed to the resistant inbred Mo20W. F2 seed were separated into yellow or white endosperm, and the resulting F2 plants were tested in the greenhouse for reaction to C. m. ssp. nebraskense. Results from this small experiment suggested that genes for susceptibility may be located on chromosome arms 4S and 7L. F2 plants grown from sugary kernels, which segregated in the progeny of the cross between A632 interchange 4S.36-6S.NOR and Mo20W, were retested since they showed rapid and systemic susceptibility to C. m. ssp. nebraskense. The retest results indicated that a gene(s) for susceptibility was present on chromosome arm 4S of inbred A632. These data, combined with results from progenies involving the M14 interchanges, suggested that 4S had a gene(s) conferring the largest effect on the susceptible response to C. m. ssp. nebraskense.
Subject Area
Agronomy
Recommended Citation
ROCHEFORD, TORBERT RICHARD, "GENETIC AND CYTOGENETIC STUDIES ON INHERITANCE OF SUSCEPTIBILITY IN MAIZE (ZEA MAYS L.) TO CLAVIBACTER (CORYNEBACTERIUM) MICHIGANENSE SSP. NEBRASKENSE (PLANT DISEASE)" (1986). ETD collection for University of Nebraska-Lincoln. AAI8629539.
https://digitalcommons.unl.edu/dissertations/AAI8629539