Morpho-physiological and Pathogenic variability among Alternaria lini and A. linicola causing Seedling and Leaf Blight of Linseed

Author: Sujata Kumari, Srinivasaraghavan A., R.B.P. Nirala, Ramesh Nath Gupta and Kalmesh Managanvi

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Abstract

A total of 19 isolates including four Alternaria linicola and 15 Alternaria lini collected from different agro-ecological zones of Bihar were studied for morpho-physiological and pathogenic variability. In A. linicola, colony colour was found to be greyish-black to grey-white with smooth colony margin. The maximum spore size was found in ALC-2 (40.2-44.6 × 9.5-10µm) with up to 9-12 horizontal and 3-4 vertical septation. Days taken to sporulation was found maximum in ALC-1 (14 days) and minimum in ALC-4 (10days). Similarly, colony colour in A. lini was white or whitish grey to greyish black with smooth margin. Maximum spore size was found in ALN-14 (21.4-23.6 X 12.3-12.9µm) with a septation of 5-7 × 2-3. Days taken to sporulation was found maximum in ALN-1, 6 & 15 (16 days) and minimum in ALN-3 & 12 (11days). Maximum growth on potato dextrose agar (PDA) was achieved after two weeks of incubation. The mean mycelial dry weight of six isolates measured at different temperature conditions revealed that 25 °C was the most favorable condition for mycelium production (57.2mg). Among the different isolates, ALN 15 (44.2mg) was found to be performing better at all temperatures. Interestingly, the A. linicola isolates performed better at lower temperatures (15 °C). Similarly, the Relative Humidity (RH) of 90 per cent was found better for all the isolates tested except ALN-4 where maximum radial growth (37.3) was found at 80 per cent RH. The Detached leaf technique was found useful in differentiating the isolates and may be employed for screening of germplasm. Among the different isolates, ALN-4 isolated from lower leaves from the oil seed field of BAU farm was found more aggressive than other isolates.

Keywords

Alternaria lini, A. linicola, seedling blight, Linseed, Detached leaf assay

Conclusion

The present investigation has revealed considerable variability among both Alternaria lini and Alternaria linicola causing seedling blight and leaf blight respectively. Considering the level of variability the breeding programme must focus on identification of durable resistance to both the distinct pathogens which often co-exists and incite mutually confusing symptoms.

References

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How to cite this article

Sujata Kumari, Srinivasaraghavan A., R.B.P. Nirala, Ramesh Nath Gupta and Kalmesh Managanvi (2023). Morpho-physiological and Pathogenic variability among Alternaria lini and A. linicola causing Seedling and Leaf Blight of Linseed. Biological Forum – An International Journal, 15(8a): 434-440.