New approaches towards the shortening of generation cycles for faster breeding of protein legumes

In order to shorten generation cycles, a greenhouse strategy was used as control and compared with an in vitro plus in vivo strategy for pea and bambara groundnut, as well as to an in vitro only strategy for pea and grass pea. Using an in vitro plus in vivo system and embryo axis explants, nearly six generations per year for Pisum and over four generations for Vigna were obtained, compared with two generations in the field. Using successive generations from seed to seed in pea, the mean duration for one generation was 67.2 +/- 4.6 days in 'Frisson', against a mean of 143 +/- 3 days in the field. With the in vitro only strategy in pea, 6.87 generations per year were obtained with 'Frisson' and 5.24 with 'Terese', while with grass pea genotypes over three generations per year were possible. All plants obtained were morphologically normal and fertile. These results show the feasibility of using such strategies to reduce significantly the duration of generation cycles in legumes, thus offering novel approaches for breeding these important crops.