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.

scholarly journals Identification and Inheritance of Delayed First Pustule Appearance to Common leaf Rust in Sweet Corn

1995 ◽  
Vol 120 (4) ◽  
pp. 667-672 ◽  
Author(s):  
G.R. Gingera ◽  
D.W. Davis ◽  
J.V. Groth
Keyword(s):  
Disease Severity ◽  
Partial Resistance ◽  
Sweet Corn ◽  
Rank Correlation ◽  
Corn Hybrids ◽  
Breeding Lines ◽  
Puccinia Sorghi ◽  
Mean Delay ◽  
Field Environment ◽  
Wide Range

Partial resistance effectively reduces common leafrust (Puccinia sorghi Schw.) epidemics in sweet corn (Zea mays L.). One measurable field component of partial resistance is delayed first pustule appearance (FPA), influenced by latent period and infection efficiency. This is the first report of delayed FPA against common rust in sweet corn. Our objectives were to determine 1) if differences in delayed FPA could be assessed in a field environment, 2) the relationship between delayed FPA and disease severity, and 3) the inheritance of delayed FPA. FPA was screened in a field environment during 1992 and 1993 using two susceptible U.S. station inbreds and 32 breeding lines selected for partial resistance to common rust. The range in mean delay in FPA on a genotype basis was 2.4 to 5.0 days in 1992 and 1.5 to 7.4 days in 1993. Although the rank correlation of genotypes between years was small (r = 0.27), several breeding lines had longer delayed FPA in both years while others produced shorter FPA delay in both years. Seven commercial sweet corn hybrids with a wide range of partial resistance did not differ (P ≤ 0.05) for delayed FPA. There was no correlation between disease severity and delayed FPA (r2 = 0.00 to 0.21) for breeding lines or commercial hybrids, indicating that selection for delayed FPA may be conducted independently of disease severity. In a generation mean analysis conducted in 1993 and 1994 for three high x low delayed FPA crosses, the genetic control of delayed FPA was primarily additive. Dominant genetic effects were found in two crosses and epistasis was not significant in any cross.

scholarly journals Bacterial Leaf Blight on shrunken-2 Sweet Corn

Plant Disease ◽  
1997 ◽  
Vol 81 (11) ◽  
pp. 1293-1298 ◽  
Author(s):  
J. K. Pataky ◽  
L. J. du Toit ◽  
M. R. Kerns
Keyword(s):  
Sweet Corn ◽  
Inbred Lines ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Economic Losses ◽  
Corn Hybrids ◽  
Slope Coefficient ◽  
Foliar Symptoms

Severity of bacterial leaf blight (BLB, caused by Acidovorax avenae subsp. avenae) on shrunken-2 (sh2) sweet corn hybrids grown in BLB-conducive environments and sporadic outbreaks of BLB in recent years warranted evaluations of the potential for this disease to cause economic losses. BLB symptoms on 122 sh2 hybrids, 30 sh2 inbred lines, and 29 crosses of the inbreds and the effects of BLB on yield (ear weight and marketable ears) were evaluated in 1994 and 1996. BLB severity ratings for 122 hybrids averaged 3.3 and 3.7 (on a scale of 1 to 9) in 1994 and 1996, respectively. Hybrid means ranged from 1.8 to 5.5 in 1994 and from 1.9 to 5.7 in 1996, with Bayesian LSD values of 1.20 and 1.22, respectively. There were no differences in BLB ratings among hybrids with yellow, white, or bicolored kernels. Severity of symptoms on 30 sh2 inbreds ranged from 1.5 to 5.7, whereas the reactions of 29 crosses of the inbreds ranged from 1.9 to 5. The slope coefficient of the regression of crosses on mid-parent values was not different from 1. Thus, mid-parent values gave a good indication of severity of BLB symptoms on crosses, with the exception of a few crosses that tended to be more severely infected than expected based on mid-parent values. Ear weights and number of marketable ears differed among hybrids in the 1994 trial, but there was no significant effect of BLB treatments on either of these measures of yield. In 1996, ear weights in inoculated plots were 10 and 15% lower than those from noninoculated plots for 2 of 12 hybrids. Despite moderately severe foliar symptoms, BLB did not affect yield substantially in these trials even among hybrids with the most susceptible reactions.

Effects of hybrid susceptibility and inoculation timing on Goss’s bacterial wilt and leaf blight severity and corn yield

Plant Disease ◽  
2021 ◽  
Author(s):  
Elizabeth C Bauske ◽  
Andrew J Friskop
Keyword(s):  
Disease Severity ◽  
Bacterial Wilt ◽  
Field Experiments ◽  
Yield Loss ◽  
Leaf Blight ◽  
Corn Yield ◽  
Yield Losses ◽  
Sequential Combination ◽  
High Level ◽  
Growing Region

Goss’s bacterial wilt and leaf blight (Goss’s wilt) of corn is the most important corn disease in North Dakota (ND), and yield loss due to the disease has not been reliably quantified in northern corn growing regions. To help quantify the amount of yield loss caused by Goss’s wilt, a total of six field experiments were conducted from 2015 to 2017. Experiments were designed in a randomized complete block with a split plot arrangement. Hybrids served as main plots and Clavibacter nebraskensis (Cn) inoculation timings as sub-plots. Three hybrids were used and classified as a susceptible, moderately susceptible, and resistant. Inoculation timings included a non-inoculated control, six to ten leaf collars (V6 to V10), reproductive silk stage (R1), or a sequential combination of V6 to V10 and R1. A high level of disease (greater than 50% on susceptible hybrid) occurred in three experiments, a low level of disease (less than 5% on susceptible hybrid) in one experiment, and no disease was reported in two experiments. A combined analysis of the high disease experiments indicated yield losses of 34 to 41% on the susceptible hybrid when Cn inoculation occurred at V6 to V10. Yield losses of 22 to 25% occurred on the moderately susceptible hybrid when C. nebraskensis inoculation occurred at V6 to V10, and statistical differences in yield loss were not found among inoculations timings on the resistant hybrid. Correlation analyses suggest that for every 1% increase in R1 disease severity on the susceptible hybrid, yield was reduced by 117 kg/ha (1.9 bu/A). The current study further demonstrates the importance of hybrid resistance and provides updated yield loss information on Goss’s wilt in a northern corn growing region.

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