F1 hybrid inviability in Eucalyptus: the case of E. ovata × E. globulus
F1 hybrid inviability in Eucalyptus: the case of E. ovata × E. globulus
复制标题
桉树中 F1 杂种的不存活性：以 E. ovata × E. globulus 为例
作者：
G. Lopez;B. Potts;P. Tilyard
比较了两种共生林木卵形桉和蓝桉的近亲繁殖和杂交对适应度的影响，旨在解释它们在自然界中杂交的稀有性。在田间试验中，对自花授粉、开放授粉、两个物种异型杂交以及种间杂交的成功进行了监测，从结籽到 10 年的生长。仅与 E. ovata 雌性获得的种子杂交存在单方面障碍。与种内杂交型相比，F1 杂种在生命周期的几乎所有阶段都表现出较低的生存能力，并且与它们在自然界中直接竞争的开放授粉 E. ovata 半同胞相比，明显处于选择性劣势。卵形桉和蓝桉的开花时间重叠，但 F1 杂交种的开花时间较晚，几乎与任何一个物种都没有重叠。 F1 杂交种的异步开花和繁殖适应性下降将明显限制高世代杂交的机会。近亲繁殖同样对两个物种的适应性产生有害影响，并且 F1 杂种与 E. ovata 自身最具竞争力。有人认为，亲本种群近交水平的变化可能是影响杂种相对适应性及其对纯种基因库影响潜力的关键因素。通过近亲繁殖降低纯种的适应性可能会导致杂交对小型创始人或残余种群产生最大的进化影响。
The impact of inbreeding and hybridization on fitness was compared in the two co-occurring forest tree species, Eucalyptus ovata and E. globulus, aimed at explaining the rarity of their hybrids in nature. The success of selfing, open-pollination and outcrossing of both species and interspecific hybridization was monitored from seed-set to 10-year’s growth in a field trial. There was a unilateral barrier to hybridization with seed-set obtained only with E. ovata females. The F1 hybrids exhibited reduced viability compared to intraspecific cross-types at virtually all stages of the life cycle and are clearly at a selective disadvantage compared with their open-pollinated E. ovata half-sibs with which they would directly compete in nature. Eucalyptus ovata and E. globulus overlap in their flowering time but the F1 hybrids flowered later with virtually no overlap with either species. The asynchronous flowering and reduced reproductive fitness of F1 hybrids would markedly limit the opportunity for advanced generation hybridization. Inbreeding similarly had a deleterious effect on the fitness of both species, and the F1 hybrids were most competitive with the E. ovata selfs. It is argued that changes in inbreeding levels of parental populations may be a key factor affecting the relative fitness of hybrids and their potential to impact on the pure species gene pool. Reduced fitness of the pure species through inbreeding may result in hybridization having its greatest evolutionary impact in small founder or relict populations.
果蝇同胞物种之间杂种雄性不育的遗传学：种间研究揭示了复杂的上位性网络。
影响因子：
3.3
作者：
Palopoli,MF;Wu,CI
通讯作者：
Wu,CI