HAPLODIPLOIDIZATION OF MAIZE (ZEA-MAYS L) THROUGH INDUCED GYNOGENESISASSISTED BY GLOSSY MARKERS AND ITS USE IN BREEDING

Reliable detection of haploids at the seedling stage is a prerequisite for the use of haplodiploidization through in situ gynogenesis in mai ze breeding. The use of recessive alleles of glossy genes as markers m akes this detection possible in various materials. Two synthetics with a wide genetic basis: flint glossy1 CGT and dent glossy6 DGT were stu died. After pollination with the FIGH 1 inducer, they produced haploid seedlings at a rate of 0.64 and 0.93%, respectively. The rate is incr eased (0.94% on average) for the CGT (C-0) synthetic after selfing, in S-1 progenies. The distribution of 203 S-1 families showed a signific ant deviation in comparison with a Poisson distribution. The DCT synth etic showed an increase in induction rate when a new synthetic was for med with doubled haploid (DH) lines, suggesting that 'inductibility' m ay have some genetic effects. No spontaneous doubling was shown by the haploid seedlings of either synthetic. Colchicine treatment allowed a recovery of male fertility in 30 to 60% of detected haploids accordin g to the experiments. The progeny recovery rate was influenced by the genetic basis, as the DGT synthetic gave better results than the CGT s ynthetic. The growing period also had an influence upon the recovery o f fertile ears. Hybrids produced from heterotic DH lines showed an agr onomic potential similar to standard hybrids. It is concluded that in situ gynogenesis assisted by the use of glossy markers can now be used in maize breeding.