Download - OAR@ICRISAT

(shorl stature), and 18.6 x 10" (potato led character) were observed in regenerated plants
while lrequencies d only 0.6 x 10'' for male sterility and 1.7 x 10' for early ripening was
observed from EMS treatments. From inheritance studies male sterility and shot stature
appeared to behave as single gene recessive mutank potato leaf character appeared to be
in a homozygous state; and resistance was controlled by a single dominant gene.
Novak et al. (1988) compared gamma ray induced and tissue culture induced mutations in
plants derived from zygotic embryos. They observed a greater frequency of variation In tiwe
culture induced than in irradiated or Irradiated followed by in vitro regeneration treaiments.
Inadidion followed by in vitro regeneration produced chlorophyll variations of 2.07% at 5 Gray
units (Gy) and 2.23% at 10 Gy, tissue culture 1.94%, and irradiation 0.22% at 5 Gy and 0.24%
at 10 Gy. 14.25% and 9.87% of the plants regenerated in vitro after exposure to 5 Gy and 10
Gy respectively showed morphological variations. Irradiated material gave 3.4390 at 5 Gy and
2.77% at I0 Gy, and tissue culture alone gave 5.39% of morphological variants. Early flowering
variants were observed at 0.42% and 0.07% frequency when subjected to 5 and 10 Gy d
irrcdiation; 0.5% in tlssue cultured plants; 2.89% and4.1446 in regenerated plantsafter exposure
to 5 and 10 Gy respectively. Neg~itiu et al., (1984) extensively reviewed mutagenesis d
protoplasts and the selection of biochemical mutants.
All reporls agree that somaclonal variation has produced an order of magnitude grecrter
numbers of variants than EMS or irradiatlon, although the two kinds of treatments may or may
not generate the same spectrum ol mutations.