Evaluation of resistance in rapeseed lines against Sclerotinia rot (Sclerotinia sclerotiorum)

Abstract

Sclerotinia rot (SR) caused by Sclerotinia sclerotiorum (Lib) de Bary is a very serious disease of rapeseed
in northern Iran. Genotypic diversity of 26 S. sclerotiorum isolates collected from rapeseed fields in Mazandaran
province was assessed using mycelial compatibility grouping (MCG) using MCG tests, the isolates were
grouped into 10 groups that two groups were individual and the remaining eight groups were consisted of two
to four isolates. In vitro, the reaction of 7 rapeseed [Brassica napus (L.)] genotypes was investigated
against three MCGs and area under disease progress curve (AUDPC) was calculated. Wersoona and Hayola
401 with 2.90 and 3.05 and Westar with 6.65 exhibited considerably minimum and maximum level of AUDPC
respectively. Under field conditions, genotypes Z-15 exhibited high level of tolerance with disease index
54.16, while Sarigol and Z-17 demonstrated to be more susceptible to SR. Reaction of some genotypes such
as Z-15 and RGS003 was indicated similar reaction against SR under both in vitro and vivo conditions.