用RAPD和SSR分子标记鉴定小金海棠F1代 杂种实生苗的研究

小金海棠（Malus xiaojinensis）具有多种抗逆特性，是苹果属植物中一种珍贵的野生种质资源。由于小金海棠具有无融合生殖特性，早期准确、快速、有效地鉴定其F1代杂种实生苗对于研究利用其众多抗逆基因具有重要意义。RAPD技术是现有鉴定果树杂种实生苗最为简单、快速和有效的分子标记技术，但RAPD技术本身存在一定的不稳定性。笔者对小金海棠和山荆子（M. baccata）F1代杂交实生苗79个单株进行了RAPD分析，并用SSR标记对RAPD标记的初步鉴定结果进行了进一步的验证。结果显示，RAPD标记鉴定出的杂种实生苗有72.2%得到SSR标记的证实。研究的结果还表明，“叠加”和“新带”两种RAPD带型，结合RAPD标记特异位点数可以为小金海棠F1代杂种实生苗提供可靠的鉴定依据。研究为利用RAPD技术早期快速鉴定果树杂种实生苗提供了新的信息和依据。

Identification of the F1 Hybrids of Malus xiaojinensis Using RAPD and SSR Molecular Markers

Malus xiaojinensis Cheng et Jiang is resistant or tolerant to multiple environmental stresses, and thus a precious wild germplasm in the genus Malus Miller. Because of its apomictic reproduction character, an accurate and rapid identification of the F1 hybrid seedlings of Malus xiaojinensis is of great importance to both genetic study and utilization of the precious genes in the germplasm. RAPD (Random Amplified Polymorphic DNA) marker is a simple, fast, and economic molecular technique for identifying the hybrid of fruit trees, but the relatively low reproducibility of some bands is still a practical problem with the RAPD molecular technique. To find a solution to this problem, 79 F1 seedlings from M. xiaojinensis×M. baccata were first analyzed using RAPD molecular markers, and then the assumed hybrid seedlings based on RAPD makers were tested by using SSR (Simple Sequence Repeat) markers in this study. The results show that 72.2% hybrid seedlings identified based on RAPD markers are confirmed by SSR markers. Our results also show that two kinds of RPAD patterns, “combination of the parents’ bands” and “appearance of the non-parental band(s)”, used in combination with the number of the specific RAPD bands, can be to used to identify the F1 hybrid seedlings of M. xiaojinensis with good accuracy. As a result, our study provides new information on the utilization of RPAD markers in identification of hybrid seedlings of fruit trees.