New varieties and promising hybrids of Pelargonium grandiflorum hybridium hort. in humid subtropics of Russia

A genetic collection of the genus Pelargonium L’Herit. ex Ait., with 40 % stock represented by Pelargonium grandiflorum hybridium hort., is originated at the Federal Subtropical Research Centre of the Russian Academy of Sciences. The main collection varieties, including Aristo, Elegance, Candy Flowers, Hazel and Bermuda, are foreign selections attaining their best qualities under optimal soil and climatic conditions. Cultivation in humid subtropics disturbs their growth and development, at the same time as deteriorating their productivity and ornamental value. The research aimed to study the hybrid stock towards the selection of hardiest, most ornamental and long-flowering forms corresponding to a specified variety model. The variety model developed for Russian subtropic agroclimate incorporated a main set of economically valuable and adaptively significant traits. Over 30 varietal crossbreedings have been conducted to select for promising recombinants and hybrid families. A high variability of phenotypic ornamental traits has been observed in the crosses offspring. We identified 15 promising hybrids from the total morphological trait combination. Adaptive selection against stress factors has been proved effective. The most successful combinations were Hazel Ripple x Yashma, Hazel Cherry x Rozovyy Briz and A. Darling x Rozovyy Briz. A subset of elite forms (Kd-15-43, Kr-16-28 and Kc-18-22) maximising the number of significant breeding traits have further been selected towards a higher total score (≥95). K.j.-17-15, Kq-18-04 and K.ya-16-03 were recognised promising for large-flowered form selection. The Yagodnyy Tsvet variety, Kv-18-01 and K.d.-18-09 hybrids (over 35 inflorescences) have been identified as sources for high flower production. K.p-17-65, Kr-16-28 and Kc-18-22 were the hybrids with flowering period exceeding 100 days. All crosses were based on Hazel as a maternal form sourcing the trait.