B. Barnabas et al., Colchicine, an efficient genome-doubling agent for maize (Zea mays L.) microspores cultured in anthero, PL CELL REP, 18(10), 1999, pp. 858-862
The construction of maize genotypes with high haploid induction capacity ma
de it possible to study the effect of colchicine on maize androgenesis in v
itro. Anther cultures of three hybrids were treated with 0.02% and 0.03% co
lchicine for 3 days at the beginning of microspore induction. Colchicine ad
ded to the induction medium had no negative influence on the androgenic res
ponses (anther induction, induction of structures of microspore origin and
their regeneration ability) of the genotypes examined. However, significant
ly higher fertility was observed in plants originating from colchicine-trea
ted microspores, especially at 0.03%. Cytological examinations showed that
colchicine treatment before the first microspore division efficiently arres
ted mitosis and resulted in homozygous doubled-haploid microspores. Under t
he experimental conditions, the antimitotic drug had no later effect on the
division symmetry of the microspore nucleus, and unequal divisions remaine
d dominant. Callus formation from the induced microspores seemed to be more
typical (ranging between 60-70%)! but embryo frequency was increased by ap
proximately 10%, especially at the higher colchicine concentration. These r
esults suggest that the mechanism of colchicine action in premitotic maize
microspores may differ from that previously observed in wheat.