Isolation of chemically induced mutants in Borage (Borago officinalis L.)

Abstract

γ-Linolenic acid (GLA, 18:3 Δ6,9,12) has been reported to be helpful in the treatment of a wide range of disorders. Borage (Borago officinalis L.) is an annual plant of renewed interest because the seeds are an important source of CLA. The failure to retain mature seeds until harvest limits the total seed and GLA yield per plant and is the major limiting factor for the commercial production of borage. In the course of a mutagenesis program, an agronomically good line of white-flowered borage (RG-001) was treated with ethyl methane sulfonate. As a result of this program, several types of mutants were identified in the M2 generation of plants: a chlorotic mutant (type A); a mutant with increased number of sepals, petals, and ovules but reduced fertility (type B); and mutants with closed flowers (type C1) or partially opened flowers (type C2) that had increased seed retention. The type C mutants are the first reported borage plants with a nonshattering habit. After crossing type B plants with normal plants, a new mutant (type B1) was obtained with higher fertility and higher seed production per flower than those from normal plants. These mutants could be used to develop borage lines that would be superior to those currently available as a source of GLA.