Patterns of phenotypic and tuber protein variation in plants derived from protoplasts of potato (Solanum tuberosum L. CV. bintje)

Abstract Patterns of phenotypic and tuber protein variation were analysed in plants derived from protoplasts of the potato cultivar Bintje ( Solanum tuberosum L.). Phenotypic variation was analysed in plants grown under greenhouse and field conditions as well as in lightsprouts. Isoelectric focusing was used for separation of tuber proteins of second generation tuber progeny of plants derived from protoplasts (protoclones). The results showed that a wide range of phenotypic variation occurred among the protoclones. The frequency of the variant plants was much higher among the late regenerants than among early regenerants revealing the influence of culture age on variation. The analysis of first and second generation tuber progeny showed that the morphological alterations of a majority of the variant protoclones were transmitted to the tuber progeny. Some of the normal and variant protoclones segregated or showed new phenotypes among the tuber progeny, suggesting somatic segregation of chimeras. Variation in tuber protein patterns was detected in the tuber progeny of three out of 26 morphologically variant protoclones and of one among the 85 normal-looking protoclones. The tuber progeny of two protoclones showed the deletion of a protein band at pI ∼ 6, one segregated for the loss and retention of another band at pI ∼ 7 and one had a deletion of the band at pI ∼ 7. The former three protoclones originated from the same callus, and the latter one from a different callus. The origin of variation is discussed.