College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China.
PLoS One. 2012;7(8):e44337. doi: 10.1371/journal.pone.0044337. Epub 2012 Aug 30.
With the objective of combining multiple resistant traits from wild relative species in florist's chrysanthemums, trigeneric hybridization was conducted by crossing two intergeneric F(1) hybrids Chrysanthemum grandiflorum × Artemisia vulgaris and Chrysanthemum crassum × Crossostephium chinense.
METHODOLOGY/PRINCIPAL FINDINGS: To assess post-pollination phenomena, we investigated pollen germination on the stigma and embryo development, using fluorescence and scanning electron microscopy and paraffin-embedded sections, respectively. We selected eight putative trigeneric hybrid lines that showed the greatest morphological differences from the parents from among the progeny derived via embryo rescue. The hybridity of one trigeneric hybrid was further confirmed by fluorescent genomic in situ hybridization; in addition, the aphid resistance and salt tolerance of this hybrid were higher than those of the chrysanthemum parent and the C. grandiflorum × A. vulgaris F(1) hybrid, respectively.
CONCLUSIONS/SIGNIFICANCE: The enhanced aphid resistance of the hybrid line reflects the inheritance of chromosomes from A. vulgaris, which carries genes that encode bioactive components. The enhanced salt tolerance of the trigeneric hybrid is attributable to inheritance of genetic materials from Chrysanthemum crassum and Crossostephium chinense, which act to maintain the compartmentation of Na(+) and K(+) ions and their selective transportation among different organs to avert deleterious effects and protect the photosynthetic apparatus. The results indicate that trigeneric hybridization between different bigeneric hybrids is a promising method for combination of multiple stress-resistance traits for improvement of chrysanthemum.
为了将花卉菊花的野生近缘种的多个抗性性状结合在一起，我们通过杂交两个属间 F(1)杂种菊花大丽花×蒿属和菊花粗毛菊×满天星进行了三生杂种的杂交。
方法/主要发现：为了评估授粉后的现象，我们分别使用荧光和扫描电子显微镜以及石蜡包埋切片法研究了花粉在柱头上的萌发和胚胎发育。我们从通过胚胎拯救获得的后代中选择了八个表现出与亲本最大形态差异的假定三生杂种系。一个三生杂种的杂种性通过荧光基因组原位杂交进一步得到确认；此外，该杂种的抗蚜虫性和耐盐性分别高于菊花亲本和菊花大丽花×蒿属 F(1)杂种。
结论/意义：杂种系抗蚜虫性的增强反映了来自蒿属的染色体的遗传，蒿属携带编码生物活性成分的基因。三生杂种耐盐性的增强归因于菊花粗毛菊和满天星遗传物质的遗传，这些物质作用是维持 Na(+)和 K(+)离子的区室化及其在不同器官之间的选择性运输，以避免有害影响并保护光合器官。结果表明，不同双生杂种之间的三生杂交是将多个抗逆性性状结合在一起以改良菊花的一种很有前途的方法。
