Xie Li, Ke Li-Zhen, Lu Xiao-Qi, Chen Jianjun, Zhang Zhi-Sheng
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China.
Mid-Florida Research and Education Center, Environmental Horticulture Department, Institute of Food and Agricultural Sciences, University of Florida, Apopka, FL, United States.
Front Plant Sci. 2022 Jun 6;13:883470. doi: 10.3389/fpls.2022.883470. eCollection 2022.
The formation of gametes with somatic chromosome number or unreduced gametes (2 gametes) is an important process involved in the origin of polyploid plants in nature. Unreduced gametes are the result of meiotic mutations occurring during micro- and mega-sporogenesis. 2 gametes have been identified or artificially induced in a large number of plant species. Breeding of plants through 2 gametes can be advantageous because it combines genetic effects of polyploidy with meiotic recombination and sexual hybridization to produce tremendous genetic variation and heterosis. 2 gametes also occur in ornamental plants, but the potential of using 2 gametes in ornamental plant breeding has not been extensively exploited. Ornamental plants are primarily produced for their esthetic appearance and novelty, not for food and yield, and they can be readily propagated through vegetative means. Triploids, tetraploids, and plants with even higher ploidy levels produced through 2 gametes can be propagated through tissue culture to fix their phenotypes, thus leading to the development of new cultivars. In this review article, we intend to discuss the mechanisms underlying the formation of 2 gametes, techniques for 2 gamete identification, methods for enhancing 2 gamete formation, and the current status in the use of 2 gametes for development of novel ornamental plants. We believe that polyploidy breeding through 2 gametes represents a viable way of developing new cultivars, new species, and even new genera of ornamental plants.
具有体细胞染色体数目的配子或未减数配子（2n配子）的形成是自然界多倍体植物起源所涉及的一个重要过程。未减数配子是在小孢子和大孢子发生过程中发生的减数分裂突变的结果。在大量植物物种中已鉴定出或人工诱导出2n配子。通过2n配子进行植物育种可能具有优势，因为它将多倍体的遗传效应与减数分裂重组和有性杂交相结合，产生巨大的遗传变异和杂种优势。2n配子也存在于观赏植物中，但在观赏植物育种中利用2n配子的潜力尚未得到广泛开发。观赏植物主要因其美观的外观和新奇性而生产，而非用于粮食和产量，并且它们可以很容易地通过营养方式繁殖。通过2n配子产生的三倍体、四倍体以及更高倍性水平的植物可以通过组织培养进行繁殖以固定其表型，从而培育出新的品种。在这篇综述文章中，我们打算讨论2n配子形成的潜在机制、2n配子鉴定技术、增强2n配子形成的方法以及利用2n配子培育新型观赏植物的现状。我们认为通过2n配子进行多倍体育种是培育观赏植物新品种、新物种甚至新属的一种可行方法。
