Asymmetrical hybridization between Trillium apetalon and T. tschonoskii for the formation of a hybrid T. miyabeanum (Melanthiaceae)
Asymmetrical hybridization between Trillium apetalon and T. tschonoskii for the formation of a hybrid T. miyabeanum (Melanthiaceae)
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DOI：
10.1007/s00606-022-01806-2
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发表时间：
2022-04-01
影响因子：
1.9
通讯作者：
Ohara, Masashi
中科院分区：
文献类型：
--
作者：
Maekawa, Ryo;Mitani, Takuya;Ohara, Masashi
Trillium apetalon（4x）和T. tschonoskii（4x）通常在两个物种同域生长的地方杂交，导致四倍体T.产于日本北海道。本研究的目的是确定哪个隔离因子是负责的频率和不对称性的混合T。miyabeanum形成的同域种群的T. apetalon和T. tschonoskii。我们研究了T. miyabeanum形成：开花物候，育种系统，遗传隔离和杂种不活力。此外，我们还研究了开花物候对繁殖成功的影响（即，种子产量和异交率）和产量（即，胚珠产生）。apetalon和T. tschonoskii。我们计算了每个隔离障碍对总生殖隔离的绝对贡献，发现开花物候和两个亲本物种之间的繁殖系统差异在T. apetalon是母本。此外，T.作为母本的无瓣花的生活力比正反交的生活力低，并且没有达到开花期。特别是交配前隔离，特别是开花物候和育种制度的绝对贡献高于其他隔离因素的两个方向。T. miyabeanum之间杂交的不对称性，说明T. apetalon和T. tschonoskii可能是由强烈的交配前隔离引起的。隔离势垒的不对称性可促进T. tschonoskii为T.宫部。
Trillium apetalon (4x) and T. tschonoskii (4x) hybridize commonly where both species grow sympatrically, leading to the formation of tetraploid T. miyabeanum in Hokkaido, Japan. The present study aimed to determine which isolation factor is responsible for the frequency and asymmetry of hybrid T. miyabeanum formation in a sympatric population of T. apetalon and T. tschonoskii. We examined the contributions and strengths of four reproductive isolation barriers of T. miyabeanum formation: flowering phenology, breeding system, genetic isolation, and hybrid inviability. In addition, we also investigated the effect of flowering phenology on reproductive success (i.e., seed production and outcrossing rates) and outputs (i.e., ovule production) for T. apetalon and T. tschonoskii. We calculated the absolute contribution of each isolation barrier to the total reproductive isolation and found that flowering phenology and differences in breeding systems between the two parental species were more effective when T. apetalon was the maternal parent. Furthermore, hybrids with T. apetalon as the maternal parent had lower viability than those of the reciprocal cross and did not reach the flowering stage. Particularly, absolute contribution of premating isolation, especially by flowering phenology and breeding system, was higher than that of other isolation factors for both crossing directions. For the formation of T. miyabeanum, we concluded that asymmetry of hybridization between T. apetalon and T. tschonoskii would be caused by strong premating isolations. The asymmetry of the isolating barriers may promote T. tschonoskii as the maternal parent of T. miyabeanum.