RAPD analysis of Sclerotium rolfsii isolates causing collar rot of eggplant and tomato

Abstract

Eight isolates of Sclerotium rolfsii from four strategically geographical sites of Bangladesh were characterized and their cultural properties like average linear mycelial growth, colony colour, colony consistency, growth pattern and sclerotia formation were studied. Isolates varied in mycelial growth and other growth characteristics and were grouped into three. The highest linear growth was displayed by S₈. DNA concentration of eight isolates varied from 1150-7200 ng/?l. DNA fingerprinting by RAPD prompted the grouping of isolates. Selected 3 primers generated 20 bands with size ranging from 100-1500 bp. Out of the 20 bands, 9 bands (45%) were polymorphic and 11 bands (55%) were monomorphic among the eight isolates of Sclerotium rolfsii. The co-efficient of gene differentiation (G_st) was 1.000 reflecting the existence of high level of genetic variations among the 8 isolates. The lowest genetic distance and highest inter isolate similarity was found in S₁ and S₂ which would be homogeneous. The highest genetic distance and lowest inter isolate similarity found in S₃, S₇ and S₃, S₈ pair which would be most divergent isolates. The cluster analysis also revealed that S₃, S₇ and S₈ belong to different clusters. All five varieties of eggplant and tomatoes were graded as susceptible when inoculated with eight isolates. Plant mortality 93.33% was recorded in S₄, S₆ and in S₈. Considering the isolate factor the most virulent isolate would be S₈ whereas the less virulent isolate would be S₂ and S₇. Host plant of S₈ was tomato collected from Thakurgaon. S₂ and S₇ were collected from BAU farm and Dinajpur and host plants were lentil and tomato respectively. It is evident that Sclerotium rolfsii from Thakurgaon on host tomato is more virulent.

Int. J. Agril. Res. Innov. & Tech. 6 (1): 47-57, June, 2016