Cytology of multisomic addition line 'NJ04-8089' in Brassica napus L.

摘要

A B genome chromosome multi-somic addition line "NJ04-8089" in Brassica napus (AACC 2n=38)was identified from offsprings derived from BC1F1of Brassica napus/Brassica carinata (BBCC 2n=34)//B. napus. Results from cytological observation showed that somatic chromosome number was 2n=45 observed from either root-tip or baby ovary cells of "NJ048089". 7 univalent scattered around the equator at Metaphase Ⅰ(MI) of pollen mother cells (PMCs) meiosis. A chromosome configuration of 19Ⅱ + 7Ⅰ formed at MI. Some lagged chromosomes formed at Anaphase Ⅰ (AI). The 19 divalent observed could be the result of the homologous pairing of AACC chromosomes and the 7 additional chromosomes were the chromosomes of B genome coming from B. carinata according to known relationships between chromosome of A-A, C-C, A-C, B-A and B-C genome. It indicates that the 7 chromosomes likely that they originated from B genome of Brassica carinata.An unequal chromosome number with a wide range of distribution from 2n=38 to 2n=51 found in root-tip cells of seeds harvested from "NJ04-8089" plant after bagging which resulted in an unequal chromosome number in each of the gametes produced from it. Out of the total root-tip observed there was 17.28%, 13.58% and 20.99% having achromosome number of 2n=43, 2n=44 and 2n=45 respectively. It indicated that the 7 univalent was randomly assorted to each of the polar at AI but some of them acted as a group staying in one side of the cell in stead of random assorting.