Study of Some Characteristics Related to the Sexual Reproduction in Autotetraploid Vicia narbonensis

Some parameters such as frequency of pod formation, average number of seeds per pod and percentage of empty pods were used to evaluate the variation of fertility in autotetraploid Vicia narbonensis. The results showed that the autotetraploid and diploid parents had the same number of ova per gynaecium. However, the tetraploid seedling produced fewer seeds per pod and per seedling than their corresponding diploids; the poor fertilization of many ovum was probably behind the decline of fertility in the autotetraploids. Several factors may be involved: the low efficiency of diploid pollen (related to a relatively slow growth of the pollen tubes), an unbalanced meiosis for a great number of mother cells of pollen grains and a significant morphological modification of the reproductive system due to the passage from the diploid to the tetraploid state.