plant hybridization project that aims to benefit California’s floriculture industry is entering its second phase at California State University, Fresno this fall.

Following successful efforts to establish DNA "markers" for two species of the hibiscus plant, research specialist Maria Jenderek and plant science professor Arthur Olney will attempt to create a new hybrid containing the "best" characteristics of both. What could result is a hardy new landscape plant that would add brilliant color to the landscapes of inland California homes.

Of the two hibiscus species, one is H. syriacus, also known as rose of Sharon or shrub althea. It is a hardy shrub that can endure extremes in heat and cold, but it produces flowers of only "modest" size and color, noted Olney in explaining the research project. Its cousin H. rosa-sinensis, or tropical hibiscus, produces brilliant flowers but is grown only along the California coast because it can’t endure the colder inland temperatures.

"Our objective is to create somatic hybrids between these two species that will have the large showy flowers and also be cold hardy," Olney said. Although the two hibiscus are related, genetically they are "too far apart" to be crossed by conventional methods; thus the unconventional approach. The technique will include protoplast fusion, which involves isolating individual cells from each of the two species, breaking down the cell walls, and fusing the DNA-containing cell membranes together using electrical current.

"We hope to enable the cells to rejuvenate with characteristics of both species," Olney said. This will probably be the most difficult goal to achieve since the cells can easily be damaged when fused by this method, he added.

In order to determine whether the new hybrid does carry characteristics of both H. syriacus and H. sinensis, Jenderek and Olney will examine ultra-violet "photographs" of the DNA using a technique that exposes randomly amplified polymorphic DNA, or RAPD markers. This method avoids the months of time it would take to actually grow the new plants to maturity and observe the flower characteristics.

Jenderek has presented initial project results to the scientific community at the Congress on In Vitro Biology held in Washington D.C. this summer. Those same results are available in a research note just published by the California Agricultural Technology Institute (CATI). It is entitled "Development of Randomly Amplified Polymorphic DNA Markers Characteristic of Hibiscus rosa-sinensis and H. syriacus."