Negri Valeria, Tiranti Barbara
Dipartimento di Biologia Applicata, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy.
Genetica. 2010 Oct;138(9-10):985-98. doi: 10.1007/s10709-010-9485-5. Epub 2010 Sep 11.
The effectiveness of in situ (on-farm) and ex situ conservation strategies to maintain total genetic diversity was assessed in a threatened Phaseolus vulgaris L. landrace. Farmer seed lots (subpopulations) were sampled initially and then after in situ and ex situ multiplication (two locations). The number of plants used in the ex situ multiplications (120) was much larger than that normally used in germplasm bank procedures and the farmer seed lots were kept separate. In situ, the landrace was multiplied by each farmer with the usual population size. Eighty plants from the initial population, the in situ and the two ex situ multiplications were individually tested using 26 microsatellite markers. Most of the genetic parameters showed a consistent decline in the ex situ populations compared with the in situ population, with a notable loss of less frequent alleles. The differentiation among the farmer subpopulations increased when the multiplication took place outside of the adaptation area. Although 120 plants were multiplied in each ex situ cycle, a bottleneck effect was present. In addition, tests for neutrality detected three loci that are involved in pathogen response and are potentially under selective effects. The diversity conservation and the management practices of autogamous landrace crops are discussed.
在一个受到威胁的菜豆地方品种中，评估了原位（农场内）和异位保护策略对维持总遗传多样性的有效性。最初对农民种子批次（亚种群）进行采样，然后在原位和异位繁殖后（两个地点）再次采样。异位繁殖中使用的植株数量（120株）远多于种质库程序中通常使用的数量，且农民种子批次保持分开。在原位，每个农民以通常的群体规模繁殖该地方品种。使用26个微卫星标记对来自初始群体、原位繁殖群体和两个异位繁殖群体的80株植株进行单独测试。与原位群体相比，大多数遗传参数显示异位群体持续下降，频率较低的等位基因显著丢失。当在适应区域之外进行繁殖时，农民亚种群之间的分化增加。尽管每个异位繁殖周期繁殖120株植株，但仍存在瓶颈效应。此外，中性测试检测到三个与病原体反应有关且可能受到选择作用的位点。讨论了自花授粉地方品种作物的多样性保护和管理实践。
