Prunus L. (Rosaceae), a genus of over 230 species, exhibits gametophytic self-incompatibility system (GSI). In this study, we explored the patterns of variability in Plum genotypes carrying different reproductive systems, using 36 microsatellite markers (SSRs) and the S-locus. The analysis of genetic diversity showed a rich genetic variability of the studied genotypes. Linkage Disequilibrium decayed rapidly in analyzed plums reaching the significant value (r² = 0.1) at 7.5 cM. Also, we examined the patterns of variability at the end of the sixth linkage group to emphasize the effect of the S-locus on the surrounding region. The genetic diversity in the genomic neighborhood of the S-locus is related to the negative frequency dependent selection (NFDS) which can extend the high polymorphism at the selected locus to closely linked neutral sites. We conducted a drought stress on Tunisian plum to test their response. The analysis of five morphological parameters tested under drought conditions allowed selecting five plum genotypes (one hexploid and four diploid) characterized by their important tolerance to drought stress. These genotypes may be selected as important rootstock for varietal improvement.

李属（蔷薇科），属230多种，表现出配子体自交不亲和系统（GSI）。在这项研究中，我们使用36个微卫星标记（SSR）和S-基因座，研究了携带不同生殖系统的李子基因型的变异性模式。遗传多样性分析表明，所研究的基因型具有丰富的遗传变异性。连锁不平衡在分析李子迅速衰减到达显著值（[R在7.5平方厘米= 0.1）。另外，我们检查了第六个连锁群末尾的变异性模式，以强调S基因座对周围区域的影响。S基因组邻域的遗传多样性-基因座与负频率依赖性选择（NFDS）有关，其可以将选定基因座处的高多态性延伸至紧密连接的中性位点。我们对突尼斯李子进行了干旱胁迫以测试其响应。对在干旱条件下测试的五个形态学参数的分析允许选择五个以其对干旱胁迫具有重要耐受性为特征的李子基因型（一个hexploid和四个二倍体）。这些基因型可以被选作重要的砧木，以改善品种。