Assessment of heterosis and important decorative traits in new rose hybrids in F1

Abstract

The article presents the research results of intervarietal roses hybridization: the parent varieties were studied according to the main decorative indicators, the effect of heterosis of F1 hybrids over the parents was evaluated by the following traits: plants height, flower diameter, number of petals per flower, number of flowers blooming in one flowering wave (rose productivity). The analysis of inheritance of quantitative traits in hybrids according to the degree of dominance was carried out. The research was conducted in accordance with generally accepted national field and laboratory methods and standards. According to the research scheme, valuable decorative traits of introduced rose varieties were studied, parental pairs for selection were chosen, hybridization was carried out, peculiarities of heterosis manifestation and inheritance of quantitative traits in hybrids by the degree of dominance were evaluated. Valuable decorative traits in promising hybrid rose progeny were also evaluated, followed by selection of valuable genotypes to improve selective traits in new varieties. According to the research, plants height varies from 43.2 cm («Goldelse» variety) to 102 cm («Hans Gonewein Rose» variety), and the average value for the varieties is 71.4 cm. The average flower diameter was 7.6 cm, and the largest flower diameter (more than 9 cm) was observed in the varieties «Amelia», «Lidka» and «Nostalgie». The largest number of petals was in the «Cream Abundanc» variety – 67.0 pcs, while the smallest – in the «Santa Monika» variety – 15.6 pcs. The largest number of flowers per bush formed during one flowering wave was observed in «Hans Gonewein Rose» and was equal to 424.4 pcs. During the initial study of rose hybrids their main quantitative indicators were evaluated. The tallest were hybrids from the combinations P1×P3 and P2×P6 – 105.7 cm and 103.5 cm respectively. The average height of the varieties was 69.0 cm. The largest flower diameter, which exceeded 9.0 cm, was observed in hybrids from combinations: P10×P2, P9×P7 and P1×P6. The number of petals in the hybrids varied from 12 per flower to 62. Hybrids of the combinations P5×P10 and P7×P4 had the highest average number of flowers per flowering wave and were equal to 144.5 and 102.0 pcs. respectively. Compared to the parental forms, the studied offspring usually had negative true and hypothetical heterosis. The dominance degree (hp) in most hybrids had negative overdominance (hp<-1). Among the combinations the highest positive heterosis (Hip and Hspr) for the studied parameters was in hybrids P5×P10, P1×P3, P9×P7 and P1×P6. Among all first-generation hybrids negative heterosis by all indicators was found in 31.3%. For green construction and selection process as carriers of decorative valuable and biological indicators the hybrids from combinations are quite promising: P5×P10, P10×P2, P10×P5, P8×P6, P2×P6, P6×P8, P5×P6, P1×P6 and P7×P9. Key words: rose, selection, hybridization, heterosis, degree of dominance, hybrid, decorative traits.