Vol. 11, Issue 1 (2022)

Author(s):
RN Bunker and NS Tanwar

Abstract:
The present study was carried out on cultural and pathogenic variability of 8 isolates of Colletotrichum graminicola (Ces.) Wilson under laboratory and field condition. Isolates were recovered from sorghum anthracnose infected leaves of eight locations of four states viz., Rajasthan, Andhra Pradesh, Uttarakhand and Madhya Pradesh sorghum growing regions of India during 2014 and 2015. The anthracnose severity score in these locations were ranged from 4.0 to 8.0 with considerable variations in symptoms and lesions pattern. Isolates showed significant variability in cultural and morphological charters. The maximum colony diameter (88.9 mm) with highest sporulation (10.2 x 10⁴ conidia/mm²) was found in isolate Hyr Cg-08 (Hyderabad), Whereas, mean size of conidia and setae length and width was recorded from 29.7 μm to 32.4 μm x 4.8 μm to 5.3 μm and 112.8 to 134.8 x 5.4 to 5.8 µm respectively. The diameter of acervuli was ranged between195.8 to 219.4 µm. The 5 local isolates from Rajasthan were studied for their pathogenic virulence, all isolates were exhibited significant variation in latent period and anthracnose severity on 18 tested sorghum genotypes. The pooled data of two years were revealed that isolates, Udr Cg-01 (Udaipur) was the most virulent, exhibited highly susceptible reaction (7.2 to 8.5 score) on 5 sorghum lines viz; IS 2312, Kekri local, Rampur local, SU-45 and Maldandi and susceptible reaction on 6 sorghum lines followed by Bhl Cg-03 showed highly susceptible reaction (7.4 and 8.3) on 2 land race Rampur local and Kekri local respectively. Whereas, three lines IRAT 204, CSV 21 and PJ-1430 showed lowest disease score (1.9-2.5) across all the five isolates. Analysis of variation in anthracnose severity revealed that resistance in sorghum lines was variable and dependent on the environment, indicating potential differences in virulence of C. graminicola populations at different locations and over years. The resistant line can be use for further breeding programme for source of stable resistance against sorghum diseases.