Abstract

CHAVEZ, Alice  and  KOHLI², Mohan. Identification of fungi in black point disease of wheat. Investig. Agrar. [online]. 2013, vol.15, n.2, pp.133-137. ISSN 2305-0683.

The black point of wheat grains is characterized by darkening of the embryonic region of the kernels which negatively impacts the flour color and quality and is penalized at the commercial level. The National Institute of Technology, Normalization and Metrology (INTN) has established a limit on the percent of black pointed kernels to be commercialized nationally. Given the importance of this problem, the present study was designed to identify pathogens associated with the black point disease. There were analyzed the seed of 114 varieties and advanced genetic lines produced in 2012. On the other hand, the study was also utilized to determine the presence and importance of Pyricularia fungus as seed pathogen. One hundred grains were selected randomly and quantified for black point. Three to five of the infected grains of each material were seeded on the PDA culture medium in Petri dishes, which were incubated at 25°C for 6 days before identifying the colonies. All the genetic materials under study demonstrated between 1 and 8 percent of black point infection. In total 11 fungi belonging to the following genera were identified to be causing the black point in wheat grains: Curvularia, Alternaria, Helminthosporium, Fusarium, Pyricularia, Drechslera, Nigrospora, Septoria, Cladosporium, Chaetomium, and Melanospora. The pathogens Curvularia, Alternaria, Helminthosporium and Fusarium, were the most predominant fungi isolated from the black pointed kernels. The fungus Pyricularia, was identified only in six out of 114 samples studied.

Keywords : Black pointed,; wheat, fungi; pathogens.

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