EVALUATION OF MEIOSIS IN CUCUMBER (CUCUMIS-SATIVUS L) MONOHAPLOIDS

Detailed meiotic studies were conducted for the first time on nine hap loid plants representing four different genotypes of cucumber (Cucumis sativus L. n=x=7). At diakinesis and metaphase I frequency of rod typ e bivalents was very low (0.1 per pollen mother cell - PMC) being obse rved in 4.3% of PMCs of one haploid plant. The frequency of diads, tri ads and polyads (72-84%) was higher than tetrads and pollen was 100% s terile. Very rare bivalents associations and fragmentations of chromos omes are discussed as well as divisions of chromosomes up to chromonem a. It is concluded that very little chromosome homology and no evidenc e of duplication is to be found within the haploid set of cucumber chr omosomes and that the basic chromosome number is seven.