Milky mushroom, Calocybe indica which is considered as the third most popular and
ommercially grown mushroom in Asia is the result of huge revolution in the mushroom technology
recent years with respect to types and strains of cultivated mushrooms. Mutation was carried out by
pplying gamma radiation with different doses (10,250,500,750 and1000gray) on C. indica mycelia
own on Potato Dextrose Agar (PDA). Post radiation observation on the mushroom morphology was
etected. When measured 14 days after irradiation, strain 2 take less time to complete mycelia growth
nd mycelial growth of cultures treated with low dose (10 gray) was faster than that of unirradiated
ultures. High doses (250, 500, 750, 1000 gray) inhibited mycelial growth significantly. As radiation
ose increased over 250 gray, the growth parameter gradually decreased to reach a minimum at 1000
ay. Color and odor were not changed by irradiation. Mutants showed wide range of variability. In
e present study, inter simple sequence repeat (ISSR) assays were used to identify DNA
olymorphism among the mutant strains of C. indica, to identify DNA polymorphism among the
utants and non-treated (0.0gray) samples through ISSR assay, a total of 10 random primers were
creened, ISSR analysis showed high degree of variation yielding 58 bands including 40 polymorphic
ands (39 shared and one unique band with molecular size 1050 pb in ST.1 by the dose 1000 gy).
hese findings indicated a medium level of genetic diversity among the studied C. indica strains and
eir mutants. The cluster analysis revealed three main clusters ,Cluster I consisted of only fourteen
enotypes, cluster II consisted of three genotypes (CI-1.1000gy , CI-2.0gy and CI-2.10gy) while
enotype CI-1(500gy) revealed a completely different banding profile with all 10 selected primers
nd stood quite distinct from other genotypes in the final cluster .This study indicated that strains of
indica and their mutants show abundant diversity in morphological and genetic diversity, and that
NA polymorphism detected by ISSR analysis offered a useful molecular marker for the
entification of mutants in gamma radiation-treated mushroom . |
