Abstract
A total of forty one genotypes of onion were evaluated for their relative response to purple blotch complex caused by Alternaria porri and Stemphylium vesicarium under artificial epiphytotic condition in field during Rabi 2014-2015 and 2015-2016. Significant variation in disease severity among the onion genotypes was found over two years but the pooled analysis revealed that most of the variations were due to genotype x year interaction. None of the genotypes exhibited resistance to the disease complex. Of the test genotypes, eighteen were found moderately susceptible while twenty one were found susceptible to the disease complex. Two genotypes viz., Punjab Naroya and OSR-1364 exhibited highly susceptible reaction. However, six genotypes viz., P-96, P-30, P-121, OSR-1359, P-98 and OSR-1370 showed superior yield performance. Purple blotch complex exhibited highly significant negative correlation of 0.71 and 0.67 with fresh bulb yield and bulb size, respectively. Cluster analysis of onion genotypes was performed based on disease and yield variables and the genotypes were furthered grouped into five clusters based on average values of disease and yield variables.Int. J. Appl. Sci. Biotechnol. Vol 5(4): 498-504
Highlights
Onion (Allium cepa L.), known as “queen of kitchen” is one of the oldest known and important high value spice cum bulbous vegetable crop cultivated throughout India
Onion is highly susceptible to many foliar, bulb and root pathogens, which reduce its yield and quality (Cramer, 2000)
Uddin et al (2006) reported that the Stemphylium leaf blight (SLB) pathogen (S. vesicarium) is first to initiate infection, which is followed by subsequent infection by the pathogen of purple leaf blotch (PLB) (A. porri) and the disease is designated as purple blotch complex (PBC)
Summary
Onion (Allium cepa L.), known as “queen of kitchen” is one of the oldest known and important high value spice cum bulbous vegetable crop cultivated throughout India. Purple leaf blotch (PLB) caused by Alternaria porri (Ellis) Cif. and Stemphylium leaf blight (SLB) caused by Stemphylium vesicarium (Wallr.). The typical oval to elliptical lesions are colonised by either Alternaria porri, Stemphylium vesicarium or mixtures of both pathogens and Article may be cited as: R.K. Yadav et al (2017) Int. J. Since PLB + SLB are progressing together on the same host, it is considered to be a complex problem (Suheri and Price 2000 a, b). Uddin et al (2006) reported that the SLB pathogen (S. vesicarium) is first to initiate infection, which is followed by subsequent infection by the pathogen of PLB (A. porri) and the disease is designated as purple blotch complex (PBC). The present investigation was carried out to determine the source of resistance among onion genotypes against PBC under artificial epiphytotic conditions in the field
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