African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12209

Full Length Research Paper

Cultural, morphological, pathogenic and molecular characterization of Alternaria mali associated with Alternaria leaf blotch of apple

  T. A. Sofi*, Muzafer A. Beig, Gh. Hassan Dar, Mushtaq Ahmad, Aflaq Hamid, F. A. Ahangar, B. A. Padder and M. D. Shah        
Division of Plant Pathology, SKUAST- Kashmir, Shalimar, Srinagar-191121, Jammu and Kashmir, India.
Email: [email protected], [email protected]

  •  Accepted: 21 December 2012
  •  Published: 23 January 2013

Abstract

 

 

Alternaria blotch (Alternaria mali) causes severe foliar damage to apple trees in Kashmir. Twenty one (21) isolates of A. mali were collected from different locations and characterized for cultural, morphological, pathogenic and molecular variations. A. mali colonies varied in their cultural behaviour ranging from velvety to cottony, mostly appressed, with regular to irregular margins. Colour of colonies ranged between light to dark olivacious. Isolates impregnated media with colour ranging between grey to brown. Growth rate of isolates was between 5.86 to 8.21 mm/day with fast growth in isolate Am-13 and least in Am-5. Morphological variations in size, shape and septation of hyphae, conidiophore and conidia were observed in the isolates with significant variations in conidiophore and conidial septation. Average conidial size ranged from 21.36 to 31.74 x 8.34 to 14.48 µm. Isolates exhibited variations in incubation period, number and size of the lesions were produced. The dendrogram analysis, based on cultural, morphological and pathogenic studies, revealed variation within A. malipopulation. At 67% similarity matrix, all the isolates formed 2 clusters with 12 and nine isolates in cluster I and II, respectively. However, dendrogram on molecular (random amplification of polymorphic DNA, RAPD) basis revealed five clusters at 68% Dice similarity coefficient. There was no congruence between RAPD pattern and cultural, morphological and pathogenic characters. Isolates identical for one spectrum were often dissimilar for other spectrum. The results demonstrate existence of considerable variation in cultural, morphological, pathogenic and molecular characters of A. mali isolates prevalent in Kashmir valley.

 

Key words: Apple, Alternaria mali, variability, cultural, morphological, pathogenic, RAPD.

Abbreviation

RAPD, Random amplification of polymorphic DNA; UPGMA,

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