Tetraploid potato hybrids through protoplast fusions and analysis of their performance in the field.

Data on the production of tetraploid hybrid plants after electrofusion of protoplasts from various diploid (2n = 2x =24) Solarium tuberosum and S. phureja are reported. Ten different fusion combinations were used. Six hybrids with the tetraploid chromosome number 2n=4x=48 were tested under field conditions for their performance in various agronomic traits (tuber type, tuber yield, underwater weight of tubers, numbers of tubers, mean weight per tuber). Tuber yield in five of the six hybrid clones was similar to that of cv Bintje. One hybrid clone (35-4) had three times higher tuber yield than cv Bintje. The mean tuber weight of this hybrid was similar to that of cv Bintje. The results of this study prove that fertile tetraploid somatic hybrids having similar or higher tuber yield than that of cv Bintje can be obtained through somatic hybridization. This technique is now included in commercial potato breeding programs in The Netherlands.