Morphological Variation among Different Isolates of Colletotrichum gloeosporioides Isolated from Various Crops in Western Maharashtra, India

Abstract

Present investigation reveals the study of morphological variation among different isolates of Colletotrichum gloeosporioides isolated from various crops. Forty one diseased specimens were collected from different localities of Western Maharashtra and subjected to tissue isolation on PDA. Out of 41 specimens obtained from different hosts, 14 isolates from 14 various hosts were found to be pathogenic when inoculated on respective plant part. These 14 isolates were used for further study and further abbreviated as Cg-1 to Cg-14. Colletotrichum gloeosporioides isolated differed significantly in all morphological traits except the type of mycelium. Mycelium of all isolates was septate. Maximum average mycelial growth rate of 12.14 mm day -1 was observed in isolates Cg-1 and Cg-14, isolated from pomegranate and sweet orange respectively. Almost all these 14 isolates were referred as fast growing. Isolates viz. Cg-7, Cg-9, Cg-10, Cg-11, Cg-12 and Cg-13 do not produce acervuli in culture. In rest of the 8 isolates, acervuli formation was noticed within 10-25 days after inoculation. The early development of acervuli after 10 days of inoculation was observed in Cg-3, Cg-5 and Cg-8. Cg-1 from pomegranate was poor in acervuli formation ability and required more time (18-20 days). The maximum length of acervuli were recorded in Cg-2, Cg-3 and Cg-5 (175µm) respectively. While it was minimum (137.67 µm) in Cg-4 and was statistically undifferentiable from Cg-1, Cg-6, Cg-8 and Cg-14.The average size of acervuli ranged between 137.67 -175.00 X 87.67 -170 µm. Extremely large acervuli was produced in culture of Cg-5 isolated from mango. There was a considerable variation in average length of the setae. The average maximum length of setae was (87.67µm) recorded in isolate Cg-8, which was isolated from chilli. The shortest setae were observed in Cg-2 and Cg-6 having average length of 60.00µm, isolated from custard apple and strawberry respectively. The average length of setae among all these isolates was recorded in between 60.00 -87.67 µm. All these 14 isolates produced conidia in pure culture within 7 days after inoculation. The average length and width of conidia of C. gloeosporioides ranged between10.00-12.33 X 3.00-4.33 µm and this difference was statistically significant. Large sized conidia (12.33 X 4.33 µm) was recorded in Cg-8, isolated from chilli. While that of small sized conidia (10.00 X 3.00 µm) were recorded in Cg-2 and Cg-9, isolated from custard apple and ginger respectively. The maximum L X B ratio (3.33) was observed in Cg-2 and Cg-9, both these isolates were from custard apple and ginger. While it was minimum (2.75) in Cg-14 i.e. isolated from sweet orange. There was great deal of variation in the colony characters within C. gloeosporioides isolates. The colony colour was the most variable factor and none of the isolate was found to be identical with each other. The most predominant colour was creamy white to gray with various intermediate shades. While in case of colony colour at reverse, most of the isolates had...

Screening of black pepper varieties against anthracnose under nursery conditions

“…Screening black pepper against anthracnose 88 days of isolation and full growth was achieved on 8 th day. The cultural characteristics, spore morphology, pigmentation and pathogenicity of the isolated pathogen was same as reported by Sankar (2002) and Bandgar et al (2018).…”