■波斯核桃(Juglansregia)是一种经济上重要的坚果果实,因其营养丰富的内核和木材质量木材而在世界范围内种植。核桃树大多是异型的,根据基因型,一些品种是原生的,而其他人则是有质子的。尽管当雄性和雌性花朵重叠时,自交是可能的,物种的二人制促进了异交。除了有性生殖,一些报道表明,无融合生殖元素可能出现在核桃品种的商业果园中,在过去的二十年中,据报道,核桃通过无融合生殖生产坚果。然而,根据细胞胚胎学观察和/或分子标记-后代测试,没有关于无融合生殖生殖发生的可靠研究。这项研究探讨了分子和细胞学分析的结合使用,以获得对J.regia的种群遗传学和生殖系统的新见解。
■我们使用微卫星基因分型,系统分析了8种不同栽培核桃基因型的后代植物的生殖起源,并对5种栽培核桃基因型进行了细胞学研究,这些基因型是从离体花朵产生的种子集,阐明繁殖模式。
■这些细胞计数和基因分型分析不支持任何无性繁殖模式或通过种子无性繁殖,并且所研究的所有个体被鉴定为通过杂交产生的合子植物。同样,细胞学结果并没有完全证实无融合生殖的第一个成分,即无融合瘤。另一方面,根据组织学证据,不定胚似乎发生在低频率。总的来说,我们的发现表明,配子体无融合生殖的发生是不可能的。但是不能完全排除孢子体无融合生殖。
UNASSIGNED: Persian walnut (Juglans regia) is an economically important nut fruit species cultivated worldwide for its nutritious kernel and timber quality wood. Walnut trees are mostly hetero-dichogamous and, depending on the genotype, some cultivars are protogynous, while others are protandrous. Although selfing is possible when male and female blooms overlap, the dichogamy of the species promotes
outcrossing. In addition to sexual reproduction, some reports indicate that elements of apomixis may occur in commercial orchards of walnut varieties and in the last two decades, nut production by apomixis has been reported in walnut. However, there are no reliable studies on the occurrence of apomictic reproduction based on cytoembryological observations and/or molecular marker-progeny tests. This study addresses the combined use of molecular and cytological analyses to gain new insights into the population genetics and reproduction systems of J. regia.
UNASSIGNED: We systematically analyzed the reproductive origin of individual progeny plants from 8 different cultivated walnut genotypes using microsatellite genotyping and carried out cytohistological investigations of 5 cultivated walnut genotypes arising seed sets from isolated flowers, to shed light on the mode of reproduction.
UNASSIGNED: These cytometric and genotyping analyses did not support any asexual mode of reproduction or asexual propagation by seed and all individuals studied were identified as zygotic plants produced by crossing. Likewise, the cytological findings did not confirm completely the first component of apomixis, namely apomeiosis. On the other hand, according to histological evidence, adventitious embryony seems to take place at low frequency. Overall, our findings suggest that the occurrence of gametophytic apomixis is unlikely in J. regia, but sporophytic apomixis cannot be completely ruled out.