Application of aneuploid plants to plant breeding in genus Nicotiana

非整倍体在植物遗传学研究中有着重要的作用，并有可能用于植物育种。首先，为了研究在二倍体和单倍体互补体中添加额外染色体对基因平衡的影响，对欧洲林烟草（Nicotiana sylvestris）（n=x=12）进行了三体（2n+1）和二体单倍体（n+1）植株的产生试验。将三倍体与二倍体之间的F_1代植株与二倍体植株回交。从B_1代中选出61株三体植株。根据叶片形态和花形态将这些三体植物分为12个类型。利用12种类型的三体进行花药培养。在获得的二体单倍体中，有5种植株的器官发育较弱。由B220三体植株衍生的二体单倍体的花明显小且畸形，而相应的三体植株则产生正常的花和叶，且明显大于正常二倍体。Thu 关于我们 三体系B220将是一个非常有用的栽培品种。然而，在种子繁殖的物种中，额外染色体的低传递阻止了这些植物成为农业上有用的品种。在B220系中，2n × 2n+1杂交的额外染色体转移率很低。这是由于n+1花粉粒发育延迟，在开花时未完全成熟。在2n × 2n+1杂交中，延迟授粉1天和通过尼龙网选择的小花粉粒授粉增加了额外染色体的转移。特别是用30和25 μ m尼龙筛筛选的花粉，其额外染色体的转移率极高，分别为51.9%和70.4%。第二，用物理诱变剂（如X射线）处理B220二体单倍体花药中的花粉粒，可能是一种有效的方法，诱导染色体片段的复制，从而诱导大叶和大花。染色体组加倍可使复制的染色体片段部分产生纯合植株。在X射线处理的花药诱导的试管苗中发现了许多染色体畸变。然而，迄今为止，还没有获得具有农艺性状的染色体片段的有用重复的单株。看来，为了试图产生一种在农业上有用的特异性复制，将需要大量的易位。少

Aneuploids have been useful for studying the genetics of many plant species and have possibility to be used for plant breeding. Firstly, in order to investigate the genic balance influenced by addition of an extra chromosome to diploid and haploid complements, an experiment was carried out on the production of trisomic (2n+1) and disomic haploid (n+1)plants in Nicotiana sylvestris (n=x=12). F_1 plants between triploid and diploid were backcrossed with the diploid plants. Sixty one trisomic plants were selected from the B_1 progenies. These trisomic plants were grouped into 12 types by the leaf shape and flower morphology. The anther culture was performed using the 12 types of trisomics. Among the obtained disomic haploids 5 types of plants developed frower organ. The flower of disomic haploid derived from B220 trisomic plant was conspicuously small and malformed, while the corresponding trisomic plant produced normal and remarkably larger flowers and leaves than the normal diploid. Thu … More s , trisomic line B220 will be very useful as a cultivar. However, in seed-propagated species, the low transimission of the extra chromosome has prevented such plants from becoming agriculturally useful cultivars. In line B220, the transfer of the extra chromosome in 2n x 2n+1 crosses was very low. This was due to the delayed development of n+1 pollen grains, which are not full maturity at the time of anthesis. The transfer of the extra chromosome in 2n x 2n+1 crosses was increased by a 1 day delay in pollination and also by pollination of small pollen grains selected through nylon meshes. Especially, pollen selected by using 30 and 25 m nylon meshes induced an extremely high transfer of the extra chromosome, namely 51.9% and 70.4%, respectively. Secondly, pollen grains in the anthers of disomic haploids of B220 treated before culture with physical mutagen such as X-rays, may be a useful method to induce the duplication of a chromosome segment which induces large leaf and flower. Doubling of genome may result in homozygous plantlets in the portion of duplicated chromosome segment. We realized many chromosome aberrations in plantlets induced by the anther treated by X-rays. No single plant with a useful duplication of the chromosome segment for agronomic character, however, has been achieved until now. It seems that in order to attempt to produce a specific duplication which is useful agriculturally, a huge number of translocations will be required. Less