Introgression of Resistance to Northern Leaf Blight into Sweet Corn with the Sugary Enhancer Gene: A Genetic and Epidemiological Study

1992 ◽  
Author(s):  
John Juvik ◽  
Yehuda Levy ◽  
Jeral K. Pataky ◽  
Avri Bar Zur ◽  
David Dickinson
Keyword(s):  
Epidemiological Study ◽  
Sweet Corn ◽  
Leaf Blight ◽  
Northern Leaf Blight

scholarly journals Disease Severity and Yield of Sweet Corn Hybrids with Resistance to Northern Leaf Blight

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 57-63 ◽  
Author(s):  
J. K. Pataky ◽  
R. N. Raid ◽  
L. J. du Toit ◽  
T. J. Schueneman
Keyword(s):  
Disease Severity ◽  
Partial Resistance ◽  
Yield Loss ◽  
Sweet Corn ◽  
Correlation Coefficients ◽  
Inbred Lines ◽  
Leaf Blight ◽  
Northern Leaf Blight ◽  
Corn Hybrids ◽  
Highly Correlated

Reactions of supersweet (sh2) sweet corn to northern leaf blight (NLB) and associated yields were evaluated in Belle Glade, Florida and Urbana, Illinois in yield-loss trials, hybrid evaluations, and evaluations of breeding materials. Hybrids differed significantly for NLB in all trials. Severity of NLB ranged from 0 to 66% on 35 sh2 hybrids in yield-loss trials, and from 0 to 60% on 80 sh2 hybrids in hybrid evaluations. NLB ratings ranged from 1 to 9 (approximately 0 to 80% severity) on 375 hybrids and 186 inbred lines in evaluations of breeding materials. Various methods of rating NLB and ratings from multiple dates were highly correlated, with correlation coefficients ranging from 0.76 to 0.98. Yield, measured as weight of ears and number of marketable ears from inoculated plots as a percentage of that from control plots, decreased as disease severity increased. Linear or quadratic regression models explained 31 to 70% of the variation in percent yield as a function of disease severity at harvest. The effects of NLB on yield were limited by NLB-resistance in several hybrids, including CCO 3268, Chieftain, Crisp N Sweet 710A, Day Star, Envy, Forever, GSS 1526, Jupiter, Midship, Prime Plus, Sch 5005, and SummerSweet 7630. Although high levels of partial resistance to NLB were prevalent among 375 new experimental sh2 hybrids and 186 sh2 inbred lines evaluated in 1995, use of the gene HtN may increase in the near future as breeders are incorporating this resistance into new inbreds and hybrids. Breeders and plant pathologists would be wise to continue improving partial resistance to NLB without using the gene HtN in genotypes with adequate levels of partial resistance, because the widespread use of the gene HtN will select for virulent races of Exserohilum turcicum which occur in Florida, or for races with new combinations of virulence.

scholarly journals SWEET CORN INBREDS WITH PARTIAL RESISTANCE TO NORTHERN LEAF BLIGHT AND STEWART'S WILT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1067a-1067 ◽  
Author(s):  
A. C. Meyer ◽  
J. K Pataky ◽  
J.A. Juvik
Keyword(s):  
Partial Resistance ◽  
Sweet Corn ◽  
Leaf Blight ◽  
Exserohilum Turcicum ◽  
Northern Leaf Blight ◽  
Dent Corn ◽  
Erwinia Stewartii ◽  
Stewart's Wilt ◽  
Corn Inbred ◽  
Moderately Resistant

Approximately 200 sweet corn inbred lines were screened for two years for resistance to northern leaf blight, caused by Exserohilum turcicum, and Stewart's wilt, caused by Erwinia stewartii. Inbreds with the best levels of partial resistance to races 1 and 2 of E. turcicum included IL11d, IL676a, IL677a, IL685d, IL766a, IL767a and IL797a. Inbreds with the best partial resistance to E. stewartii included IL126b, IL676a, IL767a, IL772a, IL774g, IL797a, IL798a and M6011. Several of these resistant and moderately resistant inbreds had common ancestors; however, inspection of pedigrees suggested that resistance was derived from Puerto Rican, Bolivian, and other tropical sources and/or dent corn. Thus, many of the sweet corn inbreds may carry different genes for resistance and can be used for the development of populations with improved resistance.

Epidemiology of Northern leaf blight on sweet corn

1992 ◽  
Vol 20 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Y. Levy ◽  
J. K. Pataky
Keyword(s):  
Sweet Corn ◽  
Leaf Blight ◽  
Northern Leaf Blight

scholarly journals Reactions of Open-Pollinated Sweet Corn Cultivars to Stewart's Wilt, Common Rust, Northern Leaf Blight, and Southern Leaf Blight

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 939-944 ◽  
Author(s):  
J. K. Pataky ◽  
L. J. du Toit ◽  
P. Revilla ◽  
W. F. Tracy
Keyword(s):  
Cluster Analysis ◽  
Sweet Corn ◽  
Morphological Characteristics ◽  
Hierarchical Cluster ◽  
Leaf Blight ◽  
Northern Leaf Blight ◽  
Sources Of Resistance ◽  
Significant Difference ◽  
Southern Leaf Blight ◽  
Stewart's Wilt

Over 800 open-pollinated (OP) varieties of sweet corn were grown and named in the century prior to the development of hybrids, but only a few of the historically important OP cultivars exist today. Alleles that could improve disease resistance of modern sweet corn may be present in the OP cultivars still in existence. The objectives of this research were to compare 36 OP sweet corn cultivars to modern commercial hybrids for reactions to Stewart's wilt, common rust, northern leaf blight (NLB), and southern leaf blight (SLB), and to classify the OP cultivars based on phenotypic reactions to these four diseases. Plants were inoculated in 1994, 1995, and 1996 with Erwinia stewartii, Puccinia sorghi, Exserohilum turcicum, or Bipolaris maydis. Symptoms were rated on a whole-plot basis, and ratings were analyzed by analysis of variance (ANOVA). Means were separated by Bayesian least significant difference values. Some of the OP cultivars had phenotypes that were intermediate to moderately resistant to Stewart's wilt, common rust, NLB, or SLB, but none of the cultivars were more resistant than the best commercial hybrids. Distributions of ratings for rust, NLB, and SLB were less disperse for the OP cultivars than for commercial hybrids. Hence, the resistance of modern sweet corn germ plasm to Stewart's wilt, rust, and NLB appears to be greater than that of the OP cultivars. OP cultivars and four standard hybrids were placed into groups based on a hierarchical cluster analysis of disease reactions. The seven groups formed from the cluster analysis of disease ratings were considerably different than those formed from isozyme variation and morphological characteristics. The partial resistance of some cultivars, e.g., Golden Sunshine, Country Gentleman, Stowell's Evergreen, and Red, may be relatively diverse since these cultivars were placed in different groups based on isozyme and morphological variation. OP cultivars with moderate levels of resistance may be sources of resistance alleles not present in commercial hybrids.

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