Niigata Prefectural Library

ISHS XXX International Horticultural Congress IHC2018: International Symposium on Ornamental Horticulture and XI International Symposium on Postharvest Quality of Ornamental Plants Origin of the Rhododendron kaempferi related species and cultivars estimated by SSR analysis

Evergreen azaleas grow in acid soil and suffer from iron deficiency when cultivated in substrate with pH higher than 6.0. In order to select tolerant plants, 11 azalea genotypes were tested for 21 days in alkaline solution (pH 9), buffered with sodium hydrogen carbonate (1 g·l-1). Leaf damage, root length and mortality rate were recorded. While leaf damage and mortality rate allowed to discriminate genotypes, root development appeared not directly linked to iron deficiency tolerance. Rhododendron ‘Juko’, R. scabrum, R. macrosepalum ‘Hanaguruma’, R. x pulchrum ‘Oomurasaki’, and R. x pulchrum ‘Sen-e-oomurasaki’ resulted iron efficient genetic resources, useful for azalea cultivation and gardening in calcareous soils. On the contrary, R. obtusum ‘Kirin’, R. tosaense, R.x mucronatum ‘Fujimanyo’ and R. obtusum ‘Susogo-no-ito’ resulted iron deficiency sensitive genotypes. R. x mucronatum ‘Ryukyushibori’ and R. indicum ‘Kinsai’ showed intermediate responses.