Development of an EMS Mutant Population and Isolation of Non-pungent Mutants in Capsicum annuum

Abstract

Induction of mutation using chemical mutagens has proved a useful tool in crop improvement and has advantages over transgenic approaches in view of legislative restrictions and intellectual property. Among chemical mutagens, ethyl methanesulfonate (EMS) has been widely used to generate novel traits. An EMS mutant population has been generated consisting of about 4,000 M2 lines using a Korean landrace of Capsicum annuum, Yuwol-cho. In total, 1,480 M2 lines were evaluated for novel traits. Various mutant phenotypes were observed in the 353 M¬2 lines, which include variations in plant growth (small size, dwarfism), and in development of leaves (variegation, color, and morphological changes), flowers (inflorescence, morphology, and organ color changes) and fruits (shape and color changes). Most of these mutant phenotypes were inherited recessively. Mutants were given names according to their phenotypic characteristics with new names designated if there were no previous examples of similar phenotypes. These phenotypic data will contribute to identify novel genes controlling phenotypes related to crop improvement and genetic studies in C. annuum. Additionally, to isolate non-pungent mutant lines, pungency of mutants was firstly tested using Gibbs reagent in 917 M2 lines. A total of six non-pungent M2 lines were isolated from 917 M2 lines. HPLC analysis was performed for six M2 lines (mature green stage fruits) and these six M2 lines turned out to contain very low capsaicinoids. To confirm inheritance of non-pungency, M3 lines were generated and four individuals (221-2-1, 2, 3, 4) from one M2 line showed low-pungency. In future study, these selected mutants will be used for identification of genes controlling pungency.