2017 ASHS Annual Conference

Abutilon menziesii is an attractive ornamental shrub native to the Hawaiian Islands. The species is listed as federally endangered and is considered critically endangered on the IUCN Red List. As the plant is endemic to dry forests, it is considered to have excellent heat and drought tolerance and can be used for xeriscaping. Abutilon ×hybridum is an attractive ornamental plant having several species from South America as parents. One drawback with Abutilon ×hybridum is that flowering is reduced during the summer months in the southeastern United States. The purpose of this research was to determine if Abutilon menziesii and Abutilon ×hybridum could be hybridized. In 2014, 15 reciprocal crosses were made as each species has perfect flowers. Only one cross, Abutilon menziesii × Abutilon ×hybridum #2012-3, produced a single schizocarp with four seeds. All four seeds germinated and the resulting plants demonstrated intermediate morphological characteristics between the two parents. One hybrid seedling has survived since 2014. The hybrid is sterile and does not produce viable pollen. The period of bloom in the greenhouse is very similar between the hybrid and the male parent. Sterility may have occurred since A. menziesii is a tetraploid (2n=4x=28) whereas A. ×hybridum is a diploid with a different base chromosome number (2n=2x=16). While A. menziesii is known to hybridize with two other endemic Hawaiian species (A. eremitopetalum and A. sandwicense, ploidy unknown), this is the first report of a Hawaiian species hybridizing with a species originating from germplasm native to South America. Morphological differences between the parents and the hybrid will be discussed.