Evaluation of In Vitro Chromosome-doubled Regenerates with Resistance to Potato Tuber Moth [Phthorimaea opercullella (Zeller)]

In vitro chromosome doubling by the use of the variation induced by zeatin riboside was applied to generate tetraploid individuals to introgress potato tuber moth (PTM) resistance from diploids to tetraploids. This approach is especially important when the expression of desirable traits is strongly influenced by cytoplasmic factors. The levels of PTM resistance and yield performance was evaluated in chromosome-doubled regenerates and their corresponding original diploids. The levels of PTM resistance were maintained in the derivatives. Test of yield performance in two years indicated chromosome-doubled regenerates generally had comparable yield with their diploid original potato clones. These results demonstrated that in vitro chromosome doubling could be an effective method to convert valuable 2x potato germplasm into the 4x level without the considerable loss of PTM resistance nor productivity.