禾本科三倍体: 形成、鉴定与利用

禾本科三倍体的形成途径包括2n配子融合、倍性间杂交、多精受精和胚乳培养。其中, 2n配子融合和倍性间杂交分别为自然界和人工合成三倍体的主要途径。该文介绍了形态学观测、染色体分析、流式细胞术和分子标记等倍性鉴定方法在禾本科三倍体中的应用及其优缺点。目前, 三倍体在禾谷类作物中无直接应用价值, 但可作为通往多倍体、非整倍体和转移异源基因的遗传桥梁。多年生禾本科三倍体(特别是异源三倍体)在饲草或能源作物中已得到广泛应用, 在该类型禾本科作物中均可直接尝试三倍体育种。多倍体的三倍体育种和无融合生殖三倍体育种可作为未来禾本科三倍体的研究方向。三倍性胚乳培养可以一步合成三倍体, 多精受精可以实现遗传上3个不同基因组的一步融合, 在三倍体研究中应予以重视。鉴于2n配子融合、多精受精的稀有特性和倍性间杂交、胚乳培养频繁的染色体变异, 高通量三倍体鉴定技术的发展将是三倍体研究实现突破的关键。

Triploid in Poaceae: Formation,Detection, and Utilization

The formation pathway of triploid in Poaceae includes 2n gamete fusion, interploidy cross, polyspermy, and endosperm culture. The fusion of reduced male (n) and unreduced female gamete (2n) is the main method for forming natural triploids. Interploidy cross is the main method for synthesizing artificial triploids. The application of ploidy identification methods such as morphological observation, chromosome analysis, flow cytometry and molecular markers in gramineous triploids is introduced, and the advantages and disadvantages of different methods are also discussed. At present, triploid has no direct application value in cereal crops, but it can be used as a genetic bridge to synthetize polyploid and aneuploid, as well as to transfer alien genes from wild species to cultivated species. Gramineous triploids (especially allotriploid) are widely cultivated for forage or biofuel production, suggesting that triploidy breeding may be directly performed in this type of grasses. We discuss the future prospect of research on gramineous triploid, e.g., polyploid- and apomixis-triploid breeding. Particularly, endosperm culture can synthesize triploids in one step, and polyspermy can achieve one-step fusion of three genetically different plant genomes, which should be paid attention to in the triploidy research. Due to rare occurrence of 2n gamete fusion and polyspermy, and frequent chromosomal variation in ploidy hybridization and endosperm culture, the development of high-throughput triploid identification technology will become the key for breakthrough in triploidy generation/breeding.