SOLANUM PHUREJA GENES ARE EXPRESSED IN THE LEAVES AND TUBERS OF ANEUSOMATIC POTATO DIHAPLOIDS

The expression of leaf isozymes and tuber patatin in dihaploids derive d from the Solanum tuberosum cv. Pentland Crown was investigated. Seve n of the dihaploids were aneusomatic containing additional chromosomes from the S. phureja dihaploid inducer. Of these, four genotypes expre ssed leaf isozymes characteristic of the S. phureja dihaploid inducer, and the tubers of three aneusomatic dihaploids contained a S. phureja form of patatin. Aneusomatic dihaploids in which the proportion of ce lls containing additional S. phureja chromosomes was relatively small (i.e. 1-15 %) did not express leaf isozyme markers or patatin bands ch aracteristic of the dihaploid inducer or showed only faint expression of one or two markers. However, those with a high proportion of cells containing additional chromosomes (50-55 %) had a range of strongly ex pressed leaf isozymes that were characteristic of the dihaploid induce r and also expressed the S. phureja tuber patatin. One dihaploid genot ype was exclusively euploid (2n = 24), yet is expressed a S. phureja l eaf isozyme marker and S. phureja tuber patatin, suggesting recombinat ion or chromosome substitution between the genome of the S. phureja di haploid inducer and the cultivar Pentland Crown.