Yamaguchi Prefectural Technology Center for Agriculture and Forestry, Yamaguchi 753-0214, Japan.
Theor Appl Genet. 2011 Dec;123(8):1433-43. doi: 10.1007/s00122-011-1678-5. Epub 2011 Aug 23.
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.
通过甘蓝型油菜（AACC，2n=38）与白菜型油菜（AA，2n=20）和甘蓝型油菜（CC，2n=18）的杂交，合成了一种新的营养作物——再合成甘蓝型油菜 Hanakkori。许多研究为再合成甘蓝型油菜品种中 A 和 C 基因组的不稳定性和密切关系提供了证据。事实上，为了获得 Hanakkori 后代，产生的种子具有不稳定的形态特征，并产生了许多异型植物。在这项研究中，我们研究了花粉活力、染色体数目、结构和与各种 Hanakkori 表型相关的行为，以确定后代中不稳定表型表达的因素。Hanakkori 表型分为五种类型。花粉活力、染色体数目和体细胞有丝分裂细胞荧光原位杂交分析的结果表明，异型植物的花粉活力较低，染色体数目异常，结构中带有小染色体片段。减数分裂过程中染色体的观察表明，异型植物的减数分裂分裂导致异常明显高于同型植物。然而，在减数分裂的二价体阶段，在同型和异型植物中都经常观察到多价染色体。我们假设再合成后代中不稳定的形态特征是减数分裂中异常分裂的结果。重要的是，要选择具有正常表型、染色体结构和最小异常减数分裂的植物来稳定后代。
