Resistance status of cultivated potatoes to early blight (Alternaria solani) in Denmark

TY - JOUR

T1 - Resistance status of cultivated potatoes to early blight (Alternaria solani) in Denmark

AU - Abuley, Isaac Kwesi

AU - Nielsen, Bent Jørgen

AU - Labouriau, Rodrigo

PY - 2018/2/1

Y1 - 2018/2/1

N2 - Field experiments were conducted in 2015 and 2016 to classify the resistance level to early blight of the main potato cultivars in Denmark. A total of 38 cultivars were used. The experiment was designed as a randomized complete block design (RCBD) with four replicates. The potatoes were inoculated by spreading barley (Hordeum vulgare) kernels infested with Alternaria solani and A. alternata. Disease assessment was done at weekly intervals starting from the onset of the first symptoms. The disease progress curves (DPC) of early blight on the cultivars were compared to that of Bintje. A multivariate analysis was performed with the apparent infection rate, the relative area under the disease progress curve, the time to reach 50% severity, the daily defoliation, the disease severity in the middle of the epidemic and the duration of the epidemic to classify the resistance level of the cultivars. The analysis of the DPC of the cultivars showed that none of the cultivars was completely resistant to early blight. However, the epidemic development differed between the different cultivars. The resistance levels of the cultivars were thus classified into classes I, II, III and IV interpreted as ‘very susceptible’, ‘susceptible’, ‘moderately slow blighting’ and ‘slow blighting’, respectively. All the late maturity cultivars were classified as class IV, and the earlier maturing cultivars were either class I or class II.

AB - Field experiments were conducted in 2015 and 2016 to classify the resistance level to early blight of the main potato cultivars in Denmark. A total of 38 cultivars were used. The experiment was designed as a randomized complete block design (RCBD) with four replicates. The potatoes were inoculated by spreading barley (Hordeum vulgare) kernels infested with Alternaria solani and A. alternata. Disease assessment was done at weekly intervals starting from the onset of the first symptoms. The disease progress curves (DPC) of early blight on the cultivars were compared to that of Bintje. A multivariate analysis was performed with the apparent infection rate, the relative area under the disease progress curve, the time to reach 50% severity, the daily defoliation, the disease severity in the middle of the epidemic and the duration of the epidemic to classify the resistance level of the cultivars. The analysis of the DPC of the cultivars showed that none of the cultivars was completely resistant to early blight. However, the epidemic development differed between the different cultivars. The resistance levels of the cultivars were thus classified into classes I, II, III and IV interpreted as ‘very susceptible’, ‘susceptible’, ‘moderately slow blighting’ and ‘slow blighting’, respectively. All the late maturity cultivars were classified as class IV, and the earlier maturing cultivars were either class I or class II.

KW - cluster analysis

KW - cultivar resistance

KW - foliage maturity

KW - graphical model

KW - integrated pest management

UR - http://www.scopus.com/inward/record.url?scp=85027725039&partnerID=8YFLogxK

U2 - 10.1111/ppa.12744

DO - 10.1111/ppa.12744

M3 - Journal article

SN - 0032-0862

VL - 67

SP - 315

EP - 326

JO - Plant Pathology

JF - Plant Pathology

IS - 2

ER -