Two Crops in One Plant – Pomato

Potato, (Solanum tuberosum) the king of the tuber crops is one of the world most valuable basic food crops with the highest world demand. This tetraploid (4x = 48) annual plant belongs to the Solanaceae nightshade family grown for its starchy edible tubers. Tomato, (Lycopersicon esculentum) is a warm season crop belongs to Solanaceae family. This diploid (2x = 24) flowering plant is extensively cultivated for its edible fruits. Both of these most popular crops have accelerating high demand in the world. Therefore, scientist tried to enhance these crops efficiency using the biotechnology.

Somatic hybridization is a promising technique used to produce somatic hybrid from sexually incompatible distinct species (Figure 1). First cell walls of the diploid somatic body cells (except sperm and egg cells) are removed to create protoplast in this procedure. Mechanical method or cellulose and pectinase enzymes can be use in this process to obtain protoplast. Then these somatic protoplasts from two different species are fuse together to create a hybrid. This somatic hybrid between potato and tomato is named as pomato. Then these hybrid colonies grow on the plate and select for the precise pomoto hybrid to continue for the further growing steps. Next this pomato hybrid grows in a sterile environment on a nutrient medium following the plant tissue culture technique. Thanks to the totipotency ability of plant cells this pomato hybrid develops into a callus then to the plantlets. After few weeks of hardening process in the green house these pomato plants are ready to grow in the field. This new gene combination is leading to enhancement of the current gene pool.

Still some arguments are continuing against for the genetically modified organisms. Therefore, rather than utilizing this advance technique, simple grafting technique is widely used to produce pomato (Figure 2).  Grafting is effectively uses to yield both potatoes and tomatoes from a single pomato plant since both crops are belonging to nightshade family. So graft from tomato shoot and potato rootstock creates this pomato which increase the productivity without affecting the quality of the crop.

Pomato is a smart approach for the small space gardening specially applies in urban areas because this will save space, time and labor.

References

• Okamura M. 1994, Pomato: Potato Protoplast System and Somatic Hybridization Between Potato and a Wild Tomato. Springer-Verlag Berlin Heidelberg GmbH, Germany, <https://link.springer.com/chapter/10.1007/978-3-642-57945-5_14>, pp. 209-223.
• Melchers G., Sacristan M. D. & Holder A. A.1978. ‘Somatic hybrid plants of potato and tomato regenerated from fused protoplasts’. Carlsberg Research Communications, 43, 203-218.