Stewart's and Goss' Wilts of Corn: Yield Reduction and Genetics of Resistance

Stewart's bacterial wilt caused by Erwinia stewartii ((Smith)Dye) and Goss' wilt caused by Clavibacter michiganense subsp. nebraskense (Schuster et al., 1973) are important bacterial diseases of corn. These diseases can affect corn plants at any stage of the plant growth. Plants infected at seedling stages often are stunted and may fail to produce ears. There is evidence that dent corn is more resistant than either flint or sweet corn. Consequently most sources of resistance have been identified in dent corn with only a few in sweet corn. A 3 x 2 x 4 factorial experiment in 1985 and a 4 x 2 x 4 factorial experiment in 1986 and 1987 arranged in a split-split-plot with main plots as a randomized complete block experimental designs with four replications were performed to evaluate yield-disease severity relationships. A 7 x 7 factorial experiment arranged in a split plot with main plot as a randomized complete block design with 5 replications were used to study the genetics of resistance of reaction of corn to these two diseases. Disease severity of Stewart's and Goss' wilts and the effect of these bacterial wilts on yield were dependent on the level of resistance and on the host plant growth stage at which disease onset occurred. Sweet corn hybrids were most susceptible and yield reduction was the most when plants were inoculated by the pathogens of these bacterial diseases at 3- to 5-leaf stage. Damage threshold for both diseases was 40% severity 1 wk before harvest, beyond which sweet corn yield decreased by 17 and 19% by weight and number of ears, respectively, for each 10% increase in severity. Dominance and partial dominance for susceptibility of corn inbred to Goss' and Stewart' wilts were observed. The heritability values ranged from moderate to high and were influenced by an additive-dominant gene action. Therefore conventional recurrent selection procedures should be useful for developing corn genotypes resistant to both diseases.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Plant Pathology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Suparyono

Contributors dc:contributor

• Pataky, Jerald K.

• Agriculture, Plant Pathology

Identifier

(UMI)AAI8908859

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70618