Development of SSR Markers to Characterize Potato (Solanum tuberosum L.) Somaclones with Improved Starch Accumulation

THIS STUDY aimed to establish functional SSR markers corresponding to variations in starch accumulation in potato somaclones. In addition to the original cultivar Lady Rosetta, fourteen callus-sourced somaclones were investigated for their starch and sugar contents as well as dry matter content. Of the selected somaclones, one represented clones with the same starch content of the original cultivar and another represented those of lower starch content. The remaining somaclones have higher starch content, compared with original cultivar. The combined results of two growing seasons unveiled significant positive correlation between dry matter content and starch content which was absent when replacing starch with soluble sugars. Insignificant correlations were recorded between sugar content and starch content. Based on the transferability of SSR markers between species, six SSR primers characterizing variation in starch accumulation in sweet potatoes were exploited to assess genetic diversity among the selected potato clones. The analysis generated distinct and reproducible banding patterns with 68 bands, of which 62 were polymorphic. The utilized primers reflected high resolving power appeared in PIC of 0.457 in average and amplification of 44 unique bands, distributed in all studied clones except one of those containing higher starch content, compared with the original cultivar. This fingerprint is a prerequisite for recruiting clones with distinguished starch accumulation potential, addressed in the present study, in breeding programs targeting the improvement of starch accumulation in potato tubers. On the other hand, the utilized primers failed to establish phylogenetic relationship corresponding to starch content of the addressed clones. This may be attributed to utilization of few primers that did not cover a considerable proportion of the addressed genome.