与香蕉种质离体保存相关的几个遗传学问题

Several Genetic Considerations for the in vitro Conservation of Musa Germplasm

目前香蕉种质的离体保存主要有缓慢生长保存和超低温保存两种方法。综合有关文献综述和讨论了香蕉种质离体保存过程涉及的遗传多样性、遗传稳定性和完整性、适应等遗传学问题。在开展香蕉种质离体保存的过程中,对离体保存所带来的遗传学方面的影响加以重视并设法减少其影响十分重要:(1)香蕉的生物学特性决定了香蕉种质的离体保存主要以始于吸芽茎尖的培养物作为保存材料;为减少取样环节样本容量较小带来的影响,建议保存数量较大的种质份数。(2)离体保存尤其是缓慢生长保存会引起香蕉种质的遗传不稳定性,因此有必要进行定期的检测。目前香蕉种质遗传稳定性的检测方法主要有形态鉴别、超微结构的观察、同工酶分析和分子标记等。(3)与缓慢生长保存相比较,超低温保存除了在保存过程中香蕉种质遗传稳定性较高,在实现对香蕉种质的长期保存方面也具有明显的优越性。

At present the methods of in vitro conservation of banana genetic resources include slow growth conservation and cryopreservation. This article summarizes and discusses several genetic considerations involved in the process of in vitro conservation such as genetic diversity,genetic stability and integrity,adaptation . In the process of in vitro conservation, it is important to be aware of the genetic consequences of in vitro conservation and make efforts to reduce the impact: (1)The biological characteristics of Musa germplasm determine that shoot-tip cultures from suckers are the most common in vitro conservation material. As the sample size is generally very small, it is recommended that larger number of accessions may have to be maintained. (2)In vitro conservation especially slow growth conservation can cause the genetic instability of Musa germplasm. It is necessary to monitor germplasm accessions periodically using morphological, cytological, isozymes analytical and molecular techniques. (3) When using cryopreservation, not only the genetic stability of Musa germplasm is expected much higher than using slow growth conservation but also the long-term storage can be realized.