Development and determination of genetic similarity of parental lines and F1 hybrids in strawberry

Modern cultivated strawberry is propagated vegetatively using stolons and crowns, but this clonal propagation of strawberry makes propagation labor-intensive and time-consuming, and introduces the risk of the virus and pathogen transfer from the mother plant to the nursery plant. Therefore, there has long been a need for seed–propagated strawberry cultivars. We tested the genetic similarity of seed-propagated F1 hybrids strawberry using seven simple sequence repeat markers. We detected high (> 0.90) genetic similarity among individuals of F1 hybrids developed by crossbreeding between these inbred lines and individuals of S9 or S11 inbred lines derived from ‘Benihoppe’, ‘Toyonoka’, and ‘Akihime’, original cultivars. The genetic similarity among inbred lines increased with the advancement of selfing generations, and that of F1 hybrids produced through hybridization between inbred lines was also very high. Although the genetic similarity among these individual of inbred lines and F1 hybrids was very high, some variation was detected, but it did not result in morphological differences. With the advancement of selfing generations, the yield and fruit weight tended to decrease in the F1 hybrids. To develop commercially useful seed-propagated cultivars, the effects of different cross combinations or crossing among and within selfing generations should be investigated.