A rapid method to increase the number of F₁ plants in pea (Pisum sativum) breeding programs.

In breeding programs, a large number of F-2 individuals are required to perform the selection process properly, but often few such plants are available. In order to obtain more F-2 seeds, it is necessary to multiply the F-1 plants. We developed a rapid, efficient and reproducible protocol for in vitro shoot regeneration and rooting of seeds using 6-benzylaminopurine. To optimize shoot regeneration, basic medium contained Murashige and Skoog (MS) salts with or without B5 Gamborg vitamins and different concentrations of 6-benzylaminopurine (25, 50 and 75 mu M) using five genotypes. We found that modified MS (B5 vitamins + 25 mu M 6-benzylaminopurine) is suitable for in vitro shoot regeneration of pea. Thirty-eight hybrid combinations were transferred onto selected medium to produce shoots that were used for root induction on MS medium supplemented with a-naphthalene-acetic acid. Elongated shoots were developed from all hybrid genotypes. This procedure can be used in pea breeding programs and will allow working with a large number of plants even when the F-1 plants produce few seeds.