Stable progeny production of the amphidiploid resynthesized Brassica napus cv. Hanakkori, a newly bred vegetable
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Resynthesized Brassica napus cv. Hanakkori (AACC, 2n = 38) was produced by cross-hybridization between B. rapa (AA, 2n = 20) and B. oleracea (CC, 2n = 18) as a new vegetative crop. Many studies have provided evidences for the instability and close relationship between A and C genome in the resynthesized B. napus cultivars. In fact, seed produced to obtain progeny in Hanakkori had unstable morphological characters and generated many off-type plants. In this study, we investigated the pollen fertility, chromosome number, structure, and behavior linked to various Hanakkori phenotypes to define factors of unstable phenotypic expression in the progeny. Hanakkori phenotypes were categorized into five types. The results of pollen fertility, chromosome number, and fluorescence in situ hybridization analysis for somatic mitosis cells indicated that the off-type plants had lower pollen fertility, aberrant chromosome number, and structures with small chromosome fragments. Observation of chromosomes at meiosis showed that the meiotic division in off-type plants led to appreciably higher abnormalities than in on-type plants. However, polyvalent chromosomes were observed frequently in both on- and off-type plants in diplotene stage of meiosis. We assume that the unstable morphological characters in resynthesized progeny were the result of abnormal division in meiosis. It results as important that the plants of normal phenotype, chromosome structure and minimized abnormal meiosis are selected to stabilize progeny.
KeywordsChromosome Number Pollen Fertility rDNA Locus Chromosome Fragment Meiosis Stage
We are very grateful to Dr. Ki-Byung Lim (Brassica Genome Team, National Institute of Agricultural Biotechnology, Rural Development Administration, Korea), for providing the CentBr2 probe. This research was also supported by the regional agriculture research funding in Yamaguchi prefectural Technology Center for Agriculture and Forestry, Japan. This was supported by Female researcher training system: reform and acceleration funding in Science and Technology Promotion Funding.
- Lim KB, Hans DJ, Yang TJ, Park JY, Kwon SJ, Kim JS, Lim MH, Kim JA, Jin M, Jin YM, Kim SH, Lim YP, Bang JW, Kim HI, Park BS (2005) Characterization of rDNAs and tandem repeats in the heterochromatin of Brassica rapa. Mol Cell 19:436–444Google Scholar
- Lim KB, Yang TJ, Hwang YJ, Kim JS, Park JY, Kwon SJ, Kim JA, Choi BS, Lim MH, Jin M, Kim HI, Jong HD, Bancroft I, Lim YP, Park BS (2007) Characterization of the centromere and peri-centromere retrotransposons in Brassica rapa and their distribution in related Brassica species. Plant J 49:173–183PubMedCrossRefGoogle Scholar
- Nishi S, Kawata J, Toda M (1959) On the breeding of interspecific hybrids between two genomes, C and A of Brassica through the application of embryo culture techniques. Jpn J Breed 8:215–222Google Scholar
- Taguchi T, Sakamoto K, Terada M (1993) Variations in somatic hybrid plants between cabbage and Chinese cabbage. Plant Biotechnol 10:138–143Google Scholar
- Zhang B, Hondo K, Kakihara F, Kato M (2001) Production of amphidiploids between A and C genomic species in Brassica. Jpn Soc Breed 3:31–41Google Scholar