Abstract: In order to effectively utilize the wild strawberry resources and improve the efficiency of the establishment of the introgression line, seed setting rate and seed emergence rate of the diploid RG × octaploid Hongyu reciprocal crosses were measured, and the chromosome ploidy of the progeny of the interspecific hybrid were examined using Carbo fuchsin dyeing and flow cytometry. Leaf structure, plant type, soluble solid content and anther activity of the hexaploid RH28 and its parents were investigated. The results showed that the seed setting rate of RG × Hongyu hybrid was 22%, higher than that of Hongyu × RG (15%), and the seed emergence rate of RG × Hongyu hybrid was 12.04%, lower than that of Hongyu × RG (20.83%). The percentage of plants with different ploidy was 2x 19.57%, 3x 45.65%, 4x 19.57%, 5x 13.04% and 6x 2.17% in the progeny of RG×Hongyu hybrid, and 3x 20.0%, 4x 26.67%, 5x 26.67% and 6x 26.67% in the progeny of Hongyu×RG hybrid, respectively. Interspecific hybrid offspring RH28 plants were slightly higher than RG, with fewer branches than RG, and could produce a small number of stolons. The thickness of leaf cell tissue was between two parents, indicating that leaf tissue structure was in direct proportion to chromosome ploidy. Flower size and stamen number were between two parents. Pollen could be detected in all stages of flowering, and the vigor intensity of anther was lower than that of Hongyu, but the vigor trend of anther was similar to that of Hongyu, and it was the strongest from the big bud stage to 1^st day after flowering. Interspecific hybrid RH28 progenie showed a trend of superior in pollen activity, stolon growth characteristics, plant type, fruit quality, etc., which provided a reference for the utilization of excellent wild strawberry resources and interspecific hybrid breeding methods.

Key words: strawberry, interspecific hybridization, ploidy, hybrid seed setting rate, anther viability, hexaploid