花楸树(Sorbus pohuashanensis)与北京花楸(S.discolor)远缘杂交亲和性解析OA

[Objective]The study aims to investigate the cross-compatibility between Sorbus pohuashanen-sis and S.discolor,to provide a theoretical basis for hybrid breeding of Sorbus.[Method]The mating system and reciprocal cross-compatibility between S.pohuashanensis and S.discolor were investigated through observ-ing flowering phenology,floral characteristics,artificial pollination experiments,and fluorescence microscope ob-servation of pollen tube growth.The authenticity of hybrid progenies was identified using 11 pairs of SSR prim-ers.[Result]The full-bloom stage and end of flowering period of S.pohuashanensis occurred later than those of S.discolor.with flowering periods overlapping in mid-April.The average ovule numbers were 6.70 for S.po-huashanensis and 9.27 for S.discolor,while average pollen grains per floret were 26 666.67 and 5 757.14,re-spectively.The pollen-ovule ratio was 3 980.10 and 621.05,respectively,and the outcrossing index was 4 for both species.The stigmas of both species showed high receptivity one day before flowering and on the first flow-ering day.Pollen of both species was able to adhere to and germinate on reciprocal stigmas.Crossing combina-tion of S.pohuashanensis×S.discolor exhibited higher compatibility than crossing combination of S.discolor×S.pohuashanensis.The artificial pollination experiment indicated that the mating systems of both species were outcrossing and self-incompatible,with average fruit-setting rates of 44.10%(S.pohuashanensis×S.discolor)and 49.04%(S.discolor×S.pohuashanensis).SSR marker analysis identified 114 hybrid progenies of S.po-huashanensis and S.discolor with 100%authenticity.Only three pairs of primer combinations(sorsb3,sorse10,sorsd39)were required to identify all the hybrid progenies.[Conclusion]Both S.pohuashanensis and S.discolor exhibited outcrossing and self-incompatible mating systems,and were reciprocally cross-compatible.