2018 ASHS Annual Conference

Hardy hibiscus (H. moscheutos) is a perennial shrub with showy blooms and is hardy from USDA zones 4 to 9. Selections of hardy hibiscus were crossed with a Florida native, H. moscheutos var. incanus (swamp rose mallow), for introgressing various traits. F1 and F2 seedlings varied in phenotypic traits, particularly foliage and flower color. The objective of this study was to determine inheritance of these two traits. Two experimental lines of Hibiscus moscheutos were each crossed with swamp rose mallow and resulting F2 populations were evaluated Summer 2015. Seed for evaluating both traits was obtained from crosses and selfings conducted Summer 2016. Seedlings were planted Spring 2017 and evaluated Summer 2017 in Watkinsville, GA. From the F2 populations, foliage color was observed to fit the Mendelian inheritance ratio of 3:1, where red foliage is dominant to green. To evaluate this observation, selfing of each original parent plant and a plant from each of the F2 populations was conducted and progeny were evaluated for foliage color. Results indicated the two parental experimental lines to be homozygous dominant (χ² = 0 for each) for a gene controlling foliage color, and the other parental line, H. moscheutos var. incanus, to be homozygous recessive, having all green foliage (χ² = 0.14). Progeny from selfing a red foliage plant from each of the F2 populations also fit the expected red:green foliage values (χ² = 0 and 0.03). To evaluate inheritance of flower color, two groups of crosses were conducted: one, using a red-flowered parent with white to blush-colored parents and the second, using two red-flowered parents. Reciprocal crosses of Hibiscus xmoscheutos ‘Robert Fleming’ USPP# 14,776 with three experimental lines of H. moscheutos indicate red flower to be maternally inherited from ‘Robert Fleming.’ When ‘Robert Fleming’ was pollinated with each of the three white/blush-flowered experimental lines, progeny displayed only red/dark pink flowers. Whereas, when ‘Robert Fleming’ was used as pollinator on the three experimental lines, progeny exhibited flowers ranging from white, pink to red. Additionally, selfing of H. xmoscheutos ‘Robert Fleming’ yielded only red-flowered progeny. Reciprocal crosses between two intraspecifc experimental lines of H. moscheutos bearing red flowers yielded progeny with flower color segregating out to red, pink, and white. Flower color ratios observed suggest the trait to be controlled by two genes. This information on inheritance of foliage and flower color can prove useful for further breeding work of hardy and swamp rose mallow hibiscus.