Stabilization of new types of diploids 2n equals 22 24 through selfing of aneuploids 2n equals 21 22 derived from crossing of sesquidiploids 2n equals 29 aac and brassica campestris 2n equals 20 aa
Lee, K.H.; Namai, H.
Euphytica 60(1): 1-13
ISSN/ISBN: 0014-2336 DOI: 10.1007/bf00022252
Aneuploids with 2n = 21 and 2n = 22 derived from crossing of sesquidiploids (2n = 29, AAC) and Brassica campestris (2n = 20, AA) were selfed successively in order to follow the changes in chromosome number of the progenies for three consecutive generations. Progenies with 2n = 22, 23 and 24 obtained after selfing of S0 generation and the succeeding S1, S2 and S3 generations were analyzed in terms of pollen stainability, % seed set as well as cytogenetically based on meiotic behaviour with the aim of determining the possibility of addition of one or more alien chromosomes into n = 10 species which may lead to differentiation of single or plural disomic addition lines. The generation of aneuploids with 2n = 21 progressed in such a way that most plants seem to revert to the 2n = 20 chromosome number of B. campestris after selfing. From 2n = 22 aneuploids, however, the succeeding progenies showed high frequency of plants with two additional chromosomes which accounted for 50.6% and 52.9% of total S3 progenies via 2n = 22 and 2n = 24 S2 generations, respectively. The meiotic behaviour of these progenies indicated evidence for a rule governing the frequency distribution of chromosome number among these addition lines and high possibility to breed such disomic plants with 2n = 22. A method of selecting stable aneuploids was suggested in addition to the possible role of pollination biology at various processes of such breeding program.