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温带果树作物防治病虫害的费用已占生产费的主要部分,同时大量采用化学处理造成的环境公害正引起人们日益忧虑。因而在大多常规果树育种计划中,抗病性已成为一项重要目标。虽然在这方面已取得一些显著成就,但由于大多数果树树种的世代时间长以及遗传上的复杂性,进展甚慢。其复杂性是指栽培品种只能作为无性系而保持下来,并且不可能通过有性繁殖产生相同的基因型。由于通过体细胞突变可能在其他遗传背景不变的情况下改变少数性状,因此,其前景是引人的。在一些果树栽培品种中发生自然突变,以及在另一些果树栽培品种中诱发突变,都证明这种途径至少对某些性状来说是可行的,其中也包括了抗病性。果树作物突变育种方面的成就还很有限,一部分原因可能是这类作物固有的困难,但也可能是由于过去采用的方法有缺陷。本文报道了在果树中诱发和选择突变体的新技术,特别是提出了关于抗病性方面获得成功的一些基本准则。所需抗病性的类型毫无疑问会影响所采用的手段。在理论上,看来单基因抗性与多基因抗性相比对诱发突变引起的变异有更强的反应。但是,在苹果短枝型自然突变体和在朗阿什顿(Long Ashton)诱发苹果突变体的初步结果中所见到的复合效应证明,将一些主要病害的田间抗性作为研究对象是有理由的。
The cost of temperate fruit tree pests and diseases has accounted for the major part of the production costs, and the extensive use of chemical pollution caused by environmental pollution is cause for growing concern. Thus in most conventional fruit tree breeding programs, disease resistance has become an important goal. Although some remarkable achievements have been made in this regard, progress has been slow due to the long generation and the genetic complexity of most fruit tree species. Its complexity means that cultivars can only be maintained as clones, and it is not possible to generate the same genotype through sexual reproduction. Because somatic mutations can alter a few traits with other genetic backgrounds unchanged, their prospects are intriguing. Natural mutations in some fruit tree cultivars and mutations in other fruit tree cultivars have demonstrated that this pathway is at least feasible for certain traits, including disease resistance. Achievements in the mutation breeding of fruit tree crops are still limited, partly because of the inherent difficulties of such crops, but may also be due to the shortcomings of the methods used in the past. This article reports on new techniques for the induction and selection of mutants in fruit trees, and in particular some of the basic guidelines for success in disease resistance. The type of disease resistance required undoubtedly affects the approach taken. In theory, it seems that single-gene resistance has a stronger response to mutagenesis-induced mutations than polygenic resistance. However, the combined effect seen in the preliminary results of apple spur type natural mutants and induced apple mutants in Long Ashton demonstrated that it was justified to target field resistance in some major diseases of.