Mutation Breeding of Salvia coccinea with Ethyl Methanesulfonate

Abstract

Salvia coccinea is a valuable flowering annual that attracts hummingbirds and bees to the garden, but few cultivars are commercially available. There is a limited range of petal colors and no leaf variegation. This research aimed to improve the ornamental value of S. coccinea by inducing mutations with ethyl methanesulfonate (EMS). The standard, red-flowered species was selected for treatment by exposing seeds to 0%, 0.4%, 0.8%, or 1.2% EMS for 8, 12, or 24 hours. The optimal treatment rate was determined to be 1.2% EMS for 8 hours, which generated desirable mutations near the median lethal dose (LD50). The M1 population had a 53% germination rate and was completely morphologically uniform. By the M2, mutations included differences in leaf shape and flower size in addition to albina, chlorina, virescens, and chimeral chlorophyll changes. A 1% mutation rate was achieved in this breeding program with seven unstable mutations and six stable mutations. The normalized difference vegetation index (NDVI) values were measured to determine differences in chlorophyll content between lethal albina mutations, chartreuse chlorina and virescens mutations, and typical leaf color. Future work will investigate the stability and heritability of chlorophyll variegation by hybridizing these selections with coral-flowered accessions of S. coccinea.