Rescuing abortive inter-EBN potato hybrids through double pollination and embryo culture.

Regeneration of inter-EBN hybrids among potato species was achieved using embryo rescue techniques. Tetraploid hybrids between 4x(2EBN) Solanum stoloniferum x 4x(4EBN) S. tuberosum Gp. Andigena as well as diploid hybrids between 2x(1EBN) S. chancayense x 2x(2EBN) S. chacoense were obtained by culturing immature hybrid embryos in nutrient medium. Identification of appropriate embryo developmental stages was critical in developing a suitable protocol for rescuing viable hybrid embryos. The use of IVP clones as the second pollinator in 4x(2EBN) x 4x(4EBN) crosses reduced premature fruit drop and helped to identify triploid hybrids. Morphological and cytological examination confirmed true hybridity for a few of the regenerated plants. Male sterility and meiotic abnormalities were characteristic of the hybrids. Several S. stoloniferum-Andigena hybrids were successfully backcrossed to Gp. Andigena.