Title

Development of novel cultivars of Euonymus alatus and Lolium perenne

Date of Completion

January 2011

Keywords

Agriculture, Horticulture|Agriculture, Plant Culture

Degree

Ph.D.

Abstract

Euonymus alatus, commonly known as 'burning bush', is an extremely popular landscape plant in the United States because of its excellent fall color. As E. alatus is also highly invasive, development of sterile, non-invasive, seedless triploid E. alatus is in high demand. Here I report the first successful protocol for producing triploid E. alatus using endosperm tissues as explants. In my study, 50% of immature endosperm explants and 14% of mature endosperm explants formed compact, green calli after culture in dark for 8 weeks and then under light for 4 weeks on Murashige and Skoog (MS) medium supplemented with 2.22 μM BA and 2.69 μM NAA. Approximately, 5.6% of the immature endosperm-derived calli and 13.4% of mature endosperm-derived calli initiated shoots within 8 weeks after they were cultured on MS medium with 4.4 μM BA and 0.5 μM IBA. Eighty-five percent of shoots rooted after culture on woody plant medium (WPM) containing 4.9 μM IBA for 2 weeks and then on hormone-free WPM medium containing 2.0 g·L-1 activated charcoal for 4 weeks. Twelve independently regenerated triploid plants have been identified through flow cytometry. Because triploid plants cannot produce viable seeds, thus are sterile and non-invasive, some triploid E. alatus plant lines reported here can be used to replace the currently used invasive counterparts. ^ Perennial ryegrass (Lolium perenne L.) is an important cool-season grass used in athletic fields, lawns and golf courses. Mutation breeding technique was utilized for generating dwarf mutants of 'Fiesta 4' perennial ryegrass to reduce management costs of turfgrass. Five mutants exhibiting dwarf characteristics were selected and evaluated in the greenhouse along with the wild-type (WT) used as a control. The data from the greenhouse study indicated that the leaf extension rates of all the mutants were low and tiller counts were not significantly different compared with the WT. Among all the mutants tested, only EMS-18 plant line displayed turf characteristics superior to the WT. Two EMS mutants namely. GAD-2 and EMS-19 had lower canopy height and higher root/shoot biomass compared with the WT under field conditions. ^