A natural amphidiploid from an onion species hybrid Allium cepa L X Allium fistulosum L
Jour Heredity: 25-32
A fertile amphidiploid has been obtained from the cross A. cepa L. X A. fistulosum. This amphidiploid shows greater vegetative vigor than either parent, as evidenced by increased height, larger stomata, larger flowers, larger pollen grains, greater wt. of seed, and more rapid growth of seedlings. It is a perennial like A. fistulosum. Bulbing is intermediate. Second-generation plants are very uniform in appearance and set seed readily. The haploid number of chromosomes is 8 in both parent sp. and 16 in the amphidiploid. Meiotic behavior is fairly regular. 16 bivalents are generally found at 1st metaphase. Fragments, chroma-tin bridges, and micronuclei are observed but are less frequent than in the sterile diploid hybrids obtained from the same species cross. During meiosis both the random and localized type of chiasma formation are found in different bivalents in the same cell.