5种常绿杜鹃组杜鹃杂交亲和性及播种繁殖研究

以庐山植物园栽培的常绿杜鹃组(Sect. Ponticum)4个亚组的5种杜鹃为材料，开展了亚组间的6个种间杂交试验，包括云锦杜鹃亚组(Subsect. Fortunea)、耳叶杜鹃亚组(Subsect. Auriculata)、银叶杜鹃亚组(Subsect. Argyrophylla)和树形杜鹃亚组(Subsect. Arborea)，以坐果率、种子千粒重、萌发率、绿苗率等为评价指标，分析探讨了其种间杂交的可育性及其规律.结果表明：1)常绿杜鹃组亚组间的种间杂交坐果率为57.14%～88.89%，达到中、高级水平；2)杂交种子千粒重低于对应母本的自然结实种子，但仅井冈山杜鹃♀×皱叶杜鹃♂与母本间达到显著水平；3)杂交种子萌发率大多高于其母本自然结实的种子，表现出某种“超亲和”(super affinity)现象，但不同的亲本组合间存在一定差异；4)部分杂交组合的绿苗率显著低于母本，表现出杂交衰退(hybrid weakness)现象；5)6个杂交组合可育性综合评价得分8～10分，均达到高育型水平.结果表明，常绿杜鹃组亚组间杂交具有高可育性.该结果为常绿杜鹃组杜鹃的杂交育种提供了依据.

Study on crossing compatibility and seeding propagation of 5 Rhododendron species in Sect. Ponticum

Using 5 Rhododendron species from 4 subsections of Sect. Ponticum of genus Rhododendron in Lushan Botanical Garden as materials， including Subsect. Fortunea， Subsect. Auriculata， Subsect. Argyrophylla and Subsect. Arborea， we conducted an interspecific hybridization experiment with six cross combinations， to study the compatibility within this section. The reproducibility and discipline of interspecific hybridization were analyzed and discussed， with the fruit setting rate， 1000-seed weight， germination rate and green seedling rate as the evaluation indexes. The results were as follows. 1) The fruit setting rate of the interspecific hybridization among R. Sect. Ponticum species was 57.14%-88.89%. 2) The thousand-seed weight from the fruits of hybridization was lower than that from the female parent's natural fruits， while only the seeds of the R. jinggangshanicum ♀×R. denudatum ♂ reached a significant level. 3) The germination rate of hybrid seeds is mostly higher than that of their female parent's natural seeds. Some “super affinity” phenomenon were showed， however， there were some differences among different cross combinations. 4) The green seedling rate of some cross combinations were significantly lower than that of the female parent， indicating the hybrid weakness. 5) The comprehensive fertility evaluation scores of six cross combinations reach 8-10 points， and all of them reached high fertility level. It's concluded that the interspecific hybridizations of R. Sect. Ponticum have high fertility. This result provided a basis for the future cross breeding of R. Sect. Ponticum.