2019 ASHS Annual Conference

Caladiums are ornamental aroids often grown in containers and in the landscape for their colorful and variably-shaped leaves. For the last seven decades, Florida has been the leading producer of caladium tubers, providing essentially all the tubers used in the world. A public caladium breeding program was initiated in 1976 at the University of Florida/IFAS to satisfy Florida growers’ need for new caladium varieties. Since then, hybridization among existing varieties and rigorous selection have resulted in the development and release of more than 30 new cultivars with bright leaf colors, novel coloration patterns, multiple leaf development, and high tuber yield potential. In response to industry needs, the breeding program has included resistance to Pythium root rot, Fusarium tuber rot and bacterial blight, and tolerance to sunburn injuries as breeding objectives. Towards these objectives, a number of sources of disease resistance have been identified. A number of the released cultivars showed improved resistance to Fusarium tuber rot and tolerance to sunburns. Other breeding approaches including somaclonal variation and ploidy manipulation are being explored. Inheritance studies over the past 15 years have revealed a group of five closely linked loci controlling five important foliar traits (main vein color, leaf spots, blotches, leaf rugosity and lemon green leaf background color) and an independent locus controlling leaf type. Chromosome number variation was founded to be the main cause of high frequency somaclonal variation in caladium. In addition, research revealed a wide range of chromosome number (and nuclear DNA content) variation among caladium species.