The Affinity of Rhododendron hybridum and Several Wild Rhododendron

Using Rhododendron hybridum as the female parent, 11 wild species and 1 cultivar of Hymenanthes sub., Tsutsusi sub., Rhododendron sub., Pseudorhodorastrum sub. and Pentanthera sub. were used as the male parent for distant hybridization. The vitality of the male pollen was measured, and the fruit setting rate, seed setting rate and seed germination rate of the hybrid were statistically analyzed to explore the affinity of the distant hybridization of Rhododendron. Results show that after the hybrid of R. hybridum and different Rhododendron, their fruit setting rate, seed setting rate and seed germination rate are different, reflecting different hybrid affinities. Among them, R. irroratum, R. pachypodum, R. fuyuanense, R. delavayi, R. rigidum as the male parent, do not obtain hybrid seeds, belonging to hybrid unaffinity. As a paternal cross, R. fortune, R. simsii, R. molle and R. molle ‘Jingzhizhu’ have higher fruit set rate, seed setting rate and seed germination rate, and have strong hybrid affinity. R. decorum, R. decorum subsp. disprepes and R. yunnanense have weak affinity as a male parent.