Relationships among reactions of sweet corn hybrids to goss' wilt stewart's bacterial wilt and northern corn leaf blight
Plant Disease 69(10): 845-848
ISSN/ISBN: 0191-2917 Accession: 006301806
Reactions to Goss' wilt [Corynebacterium nebraskensis] and Stewart's bacterial wilt [Erwinia stewartii] were highly correlated at the 1% level of probability for 75 midseason to late-season maturing sweet corn hybrids evaluated in the 1984 Illinois sweet corn disease nursery and as seedlings in greenhouse trials. In the disease nursery, correlation coefficients for comparisons of disease severity ratings of Goss' wilt and Stewart's wilt range from 0.64 to 0.77. Rank correlation coefficients for comparisons of hybrid rankings based on severity ratings for Goss' and Stewart's wilt ranged from 0.66 to 0.74 and agreed with correlations of severity ratings. Similar results were obtained in greenhouse trials. The similarity of hybrid reactions to the two bacterial diseases may have resulted from plant morphological characteristics, such as plant height, or from genetic resistance. Correlations between the two bacterial diseases and northern corn leaf blight (race 1 or 2 of Exserohilum turcicum) ranged from 0.34 to 0.63. Correlations between races 1 and 2 of northern corn leaf blight ranged from 0.61 to 0.83. The similarity of hybrid reactions to the two races of E. turcicum was probably due to polygenic resistance, which displayed little or no race specificity. Hybrid reaction to rust [Puccinia sorghi] was not correlated with reactions to the other diseases.