In Vitro Mutation Induction of Saintpaulia Using Ethyl Methanesulfonate

This study has been performed to investigate the efficiency of the chemical mutagen ethyl methanesulphonate (EMS) to induce mutations in Saintpaulia. In vitro leaf sections of Saintpaulia cv. Crystobal were exposed to various EMS treatments at 0%, 0.2%, 0.4%, and 0.6% for 30, 60, 120, and 240 min after which adventitious shoots were recovered from the treated explants. Shoots producing at least six leaves were induced to root and the resulting plantlets were transplanted to soil. A total of 1838 plantlets was grown to flowering stage and 10 mutants were identified. Four of the mutants were variegated leaf chimeras and the remaining six presented variations at the level of flower color and/or fringe. Results in the present study showed the efficiency of EMS to induce in vitro mutation of Saintpaulia and the method can be used in the future to assist breeding in this popular ornamental plant.

Effect of Fertilizer Concentration on Growth of Variegated and Non-variegated Double Impatiens

Double impatiens (Impatiens wallerana) `Blackberry Ice' (variegated-leaf type) and `Purple Magic' were grown on flood benches and irrigated with 50, 100, 200, or 300 mg·L–1 N to study the effect of fertility on growth and development. Leaf, stem, bud, and total shoot dry mass exhibited a quadratic concentration effect with maximum growth for both cultivars occurring at 100 mg·L–1 N. Tissue concentrations of N, P, and K exhibited a quadratic concentration effect and increased with fertilization concentration, however, levels were higher for `Blackberry Ice' than `Purple Magic' over all fertilization concentrations. Tissue Mg levels also increased with fertilization concentration, but levels were higher for `Purple Magic'. Tissue Ca concentrations were similar for both cultivars and levels decreased as the fertilizer concentration increased. For maximum shoot growth and flower bud production, growers should apply 100 mg·L–1 N when growing double impatiens on flood benches.