Control of late blight in organic potato production: evaluation of copper-free preparations under field, growth chamber and laboratory conditions

AbstractIn organic potato production, the need for varieties with durable late blight resistance developed through classical breeding programmes is urgent. Besides late blight resistance, other variety characteristics needed in organic potato production are early canopy closure for weed suppression and good tuber dormancy to eliminate the need for (chemical) sprouting inhibition during storage, amongst others. This paper is a unique example of collaboration between researchers, farmers and professional breeders of both large, medium and small breeding companies. The aim of the resulting breeding project, Bioimpuls, was to provide a substantial impulse to both the organic and conventional potato breeding sector by enlarging the access to various sources of late blight resistance. The Bioimpuls activities include providing true seed populations for variety selection with five available sources of R-genes against Phytophthora infestans, early and advanced introgression breeding with six new R-genes, and education and communication. The results achieved over the 11-year period (2009–2019) are analysed. Many true seed populations containing multiple resistance genes are produced and selected, and a constant flow of breeding clones is entering the evaluation and positioning trials of companies. However, it will still take a considerable amount of time before varieties with stacked resistance genes will replace the new resistant single gene varieties entering the market in the next few years. Five out of six new sources of R-genes need more years of backcrossing before they are ready for commercial use. Bioimpuls successfully introduced a training course for farmer breeders, and published a manual for potato breeding.

Download Full-text

Corrigendum to: Integrated transcriptomics and metabolomics reveal induction of hierarchies of resistance genes in potato against late blight

Functional Plant Biology ◽

10.1071/fp16028_co ◽

2016 ◽

Vol 43 (12) ◽

pp. 1205 ◽

Cited By ~ 1

Author(s):

Kalenahalli N. Yogendra ◽

Ajjamada C. Kushalappa

Keyword(s):

Late Blight ◽

Resistance Genes ◽

Quantitative Resistance ◽

Potato Production ◽

Metabolic Reprogramming ◽

Specific Gene ◽

Molecular Events ◽

Pathway Regulation ◽

Molecular And Biochemical Mechanisms ◽

Resistant Genotypes

Late blight caused by Phytophthora infestans is a devastating disease affecting potato production worldwide. The quantitative resistance is durable, but the underlying molecular and biochemical mechanisms are poorly understood, limiting its application in breeding. Integrated transcriptomics and metabolomics approach was used for the first time to study the hierarchies of molecular events occurring, following inoculation of resistant and susceptible potato genotypes with P. infestans. RNA sequencing revealed a total of 4216 genes that were differentially expressed in the resistant than in the susceptible genotype. Genes that were highly expressed and associated with their biosynthetic metabolites that were highly accumulated, through metabolic pathway regulation, were selected. Quantitative real-time PCR was performed to confirm the RNA-seq expression levels. The induced leucine-rich repeat receptor-like kinases (LRR-RLKs) are considered to be involved in pathogen recognition. These receptor genes are considered to trigger downstream oxidative burst, phytohormone signalling-related genes, and transcription factors that regulated the resistance genes to produce resistance related metabolites to suppress the pathogen infection. It was noted that several resistance genes in metabolic pathways related to phenylpropanoids, flavonoids, alkaloids and terpenoid biosynthesis were strongly induced in the resistant genotypes. The pathway specific gene induction provided key insights into the metabolic reprogramming of induced defence responses in resistant genotypes.

Download Full-text

Phytoseiids as potential natural enemies of potato psyllids in organic potato production in South Texas, USA

Journal of the Acarological Society of Japan ◽

10.2300/acari.25.suppl_137 ◽

2016 ◽

Vol 25 (Supplement1) ◽

pp. S137-S145 ◽

Cited By ~ 1

Author(s):

Raul T. VILLANUEVA ◽

Gabriela ESPARZA-DIAZ ◽

Cal W. WELBOURN

Keyword(s):

Natural Enemies ◽

Potato Production ◽

South Texas ◽

Organic Potato

Download Full-text

Influence of Fertilization on the Colorado Potato Beetle,Leptinotarsa decemlineata, in Organic Potato Production

Environmental Entomology ◽

10.1093/ee/37.2.575 ◽

2008 ◽

Vol 37 (2) ◽

pp. 575-585 ◽

Cited By ~ 1

Author(s):

G. Boiteau ◽

D. H. Lynch ◽

R. C. Martin

Keyword(s):

Colorado Potato Beetle ◽

Leptinotarsa Decemlineata ◽

Potato Production ◽

Potato Beetle ◽

Organic Potato

Download Full-text

The Effects of Host Diversity and Other Management Components on Epidemics of Potato Late Blight in the Humid Highland Tropics

Phytopathology ◽

10.1094/phyto.2001.91.10.993 ◽

2001 ◽

Vol 91 (10) ◽

pp. 993-1000 ◽

Cited By ~ 50

Author(s):

K. A. Garrett ◽

R. J. Nelson ◽

C. C. Mundt ◽

G. Chacón ◽

R. E. Jaramillo ◽

...

Keyword(s):

Late Blight ◽

Potato Production ◽

Potato Late Blight ◽

Planting Density ◽

Susceptible Host ◽

Host Diversity ◽

Progress Curve ◽

Commercial Potato ◽

Diversity Effect ◽

Diversity Effects

A field study at three highland sites near Quito, Ecuador, was conducted to determine whether host-diversity effects on potato late blight would be as important as recently found in studies conducted in temperate areas. We compared three potato mixtures and use of mixtures in combination with different planting densities and two fungicide regimes. Treatment comparisons were made by absolute and relative measures of host-diversity effects and incorporating a truncated area under the disease progress curve as a means of standardizing comparisons across sites. Potato-faba intercrops consisting of only 10% potato provided an estimate of the effects of dilution of susceptible host tissue. Host-diversity effects were very different across study sites, with a large host-diversity effect for reduced disease only at the site most distant from commercial potato production. Planting density had little influence on host-diversity effects or on late blight in single-genotype stands. Fungicide use in combination with potato mixtures enhanced a host-diversity effect for reduced late blight. Potato-faba intercrops produced only a small decrease in potato late blight. Effects of host diversity on yield were variable, with the greatest increase in yield for mixtures treated with fungicides at the site most distant from commercial potato production. The effects of host diversity on late blight severity may be less consistent in the tropical highlands than in the temperate zone, but can contribute to integrated disease management.

Download Full-text

Assessing the Adequacy of the Simulation Model LATEBLIGHT Under Nicaraguan Conditions

Plant Disease ◽

10.1094/pdis-10-10-0702 ◽

2011 ◽

Vol 95 (7) ◽

pp. 839-846 ◽

Cited By ~ 5

Author(s):

Jorge Ulises Blandón-Díaz ◽

Gregory A. Forbes ◽

Jorge L. Andrade-Piedra ◽

Jonathan E. Yuen

Keyword(s):

Late Blight ◽

Simulation Model ◽

Disease Severity ◽

Field Experiments ◽

Durable Resistance ◽

Potato Production ◽

Potato Cultivars ◽

Disease Progress ◽

High Disease Severity ◽

Fungicide Control

In this study, the adequacy of the late blight simulation model LATEBLIGHT (version LB2004) was evaluated under Nicaraguan conditions. During 2007 to 2008, five field experiments were conducted in three potato-production regions in northern Nicaragua. Two susceptible (‘Cal White’ and ‘Granola’) and one resistant (‘Jacqueline Lee’) potato cultivars were evaluated without use of fungicides and with three application intervals (4, 7, and 14 days) of the fungicide chlorothalonil. The simulation model was considered adequate because it accurately predicted high disease severity in susceptible cultivars without fungicide protection, and demonstrated a decrease in the disease progress curves with additional fungicide applications, similar to that observed in the plots. The model also generally predicted inadequate fungicide control, even with a 4-day spray interval, which also occurred in the field. Lack of adequate fungicide protection would indicate the need for cultivars with higher levels of durable resistance, and that farmers should consider more effective fungicides applications (higher dosages or different chemistries) if susceptible cultivars are used.

Download Full-text

Development of Potato Late Blight Epidemics: Disease Foci, Disease Gradients, and Infection Sources

Phytopathology ◽

10.1094/phyto.1998.88.8.754 ◽

1998 ◽

Vol 88 (8) ◽

pp. 754-763 ◽

Cited By ~ 79

Author(s):

Maarten J. Zwankhuizen ◽

Francine Govers ◽

Jan C. Zadoks

Keyword(s):

Late Blight ◽

Potato Late Blight ◽

Point Sources ◽

Minor Importance ◽

Inoculum Sources ◽

Allotment Gardens ◽

Field Gradients ◽

Organic Potato ◽

The Mean

Natural potato late blight epidemics were studied to assess the relative impact of various inoculum sources of Phytophthora infestans in Southern Flevoland (the Netherlands) from 1994 through 1996. Disease surveys were combined with characterization of isolates for mating type and DNA fingerprint pattern using probe RG57. Seventy-four percent of the commercial potato fields with early foci were clearly associated with nearby infested refuse piles. Characterization of isolates from refuse piles and fields confirmed the association. Infected seed tubers, volunteer plants, and infested allotment gardens appeared to be of minor importance for late blight development in potato fields. Several foci in refuse piles, potato fields, and allotment gardens contained more than one genotype. Due to favorable weather in August 1994, infested organic potato fields became major inoculum sources, resulting in the spread of P. infestans to adjacent conventional potato fields. Analyses of disease gradients, both at the field and regional levels, confirmed the role of the organic fields as mid-season infection sources. The mean slope of field gradients downwind of refuse piles (point sources) was significantly steeper (100-fold difference) than the mean slope of field gradients downwind of organic fields (area sources). The genotypic composition of the P. infestans populations along the gradient and of the source populations in the organic potato crops did not differ significantly. Analysis of the region gradient revealed genotype-specific disease gradients. Control measures are recommended.

Download Full-text

Automatic late blight lesion recognition and severity quantification based on field imagery of diverse potato genotypes by deep learning

10.1101/2020.08.27.263186 ◽

2020 ◽

Author(s):

Junfeng Gao ◽

Jesper Cairo Westergaard ◽

Ea Høegh Riis Sundmark ◽

Merethe Bagge ◽

Erland Liljeroth ◽

...

Keyword(s):

Deep Learning ◽

Late Blight ◽

Disease Severity ◽

Severe Disease ◽

Learning Algorithms ◽

Resistance Breeding ◽

Potato Production ◽

Majority Voting ◽

Lesion Segmentation ◽

Fast Evaluation

AbstractThe plant pathogen Phytophthora infestans causes the severe disease late blight in potato, which results in a huge loss for potato production. Automatic and accurate disease lesion segmentation enables fast evaluation of disease severity and assessment of disease progress for precision crop breeding. Deep learning has gained tremendous success in computer vision tasks for image classification, object detection and semantic segmentation. To test whether we could extract late blight lesions from unstructured field environments based on high-resolution visual field images and deep learning algorithms, we collected ~500 field RGB images in a set of diverse potato genotypes with different disease severity (0-70%), resulting in 2100 cropped images. 1600 of these cropped images were used as the dataset for training deep neural networks. Finally, the developed model was tested on the 250 cropped images. The results show that the intersection over union (IoU) values of background (leaf and soil) and disease lesion classes in the test dataset are 0.996 and 0.386, respectively. Furthermore, we established a linear relationship (R2 = 0.655) between manual visual scores of late blight and the number of lesions at the canopy level. We also learned that imbalance weights of lesion and background classes improved segmentation performance, and that fused masks based on the majority voting of the multiple masks enhanced the correlation with the visual scores. This study demonstrates the feasibility of using deep learning algorithms for disease lesion segmentation and severity evaluation based on proximal imagery for crop resistance breeding in field environments.

Download Full-text