In onion, seven stages of umbel development were distinguished with regard to the size of umbels, flower buds and developmental stages of male and female gametophytes. At the beginning of blooming, the stage at which buds are most often collected for induction of gynogenesis, flower bud length ranged from 2.0 to 5.0 mm, and the stages from archesporial cell to mature embryo sac were observed in the ovules. Microspores and bicellular pollen grains were observed in the anthers. Flower bud size was not an accurate indicator of pollen development. Buds of the same size but originating from umbels at different developmental stages were characterized by different stages of pollen development.
The aim of our study was to evaluate the genetic relationship of Rhododendrons from Rhododendron collection at Tomaszkowice in Pogórze Wielickie. Leaves and leaf buds of three evergreen Asiatic species: R. aureum, R. brachycarpum, R. purdomii, six cultivars from Catawbiense Hybridum group (R. catawbiense): Catharine van Tol, Nova Zembla, Album Novum, Boursoult, Old Port, Hachmann’s Charmant and one cultivar from Yakushimanum Hybridum group: Koichiro Wada were investigated. Two plants from each accession were analysed. DNA was isolated by Ziegenhagen and Scholz [1998] protocol, dedicated to the difficult species in terms of high quality DNA extraction. After isolation, DNA was amplified with 19 RAPD primers. We obtained 255 RAPD markers and worked out a dendrogram, which illustrated the level of genetic diversity among the tested plants. Our study confirmed a close relationship between rhododendrons from Catawbiense Hybridum group. Another group was constituted by R. aureum and R. purdomii. The third group consisted of R. brachycarpum and Koichiro Wada cv.