Israel is often in the news, but rarely as the center of some of the greenest advances in modern agriculture. Without Israeli ingenuity, low-pressure drip irrigation would never have come into use. Today the emitter device invented there is the foundation for water-conservation gardening around the world.

But Israel is also hard at work testing fruiting plants from dry climates around the world. Its dwindling water supply demands new and innovative dryland crops that offer new types of food. Among the most promising fruits for arid-zone American gardens is the apple cactus, Cereus peruvianus. This large, branching treelike columnar cactus produces some of the most delicious and beautiful fruits for gardens.

The species originates in Peru, which is evidenced by its botanical name. There it is known as pitaya. The plants have long contributed to the indigenous food supply. They were imported into Southern California long ago and are well established in both residential and botanical gardens.

Israeli farmers received their original seed from the same California botanical gardens. In Israel, they were planted in a massive study to determine how varied a species it was in terms of both fruit quality and water demand. They didn't want cuttings because these would be all identical clones of the parent plant. Only by growing from seed could the agronomists find the best producers, which would become their parent stock. Cuttings from these outstanding individuals will be the progenitors of Israel's apple-cactus orchards.

Salinity in the water is a common problem in the Middle East, so these seedlings were tested for tolerance of alkaline conditions. They would survive on reclaimed or desalinated water, which can result in increasingly alkaline soils. The cactus was also studied for spine density, for those with few spines would be far less painful to cultivate and harvest. Finally, the density of flowers and ease of pollination were observed to ensure the parent plants would be prolific. Ultimately, these plants passed their tests and became one of the most innovative crops for Israel and elsewhere in the world where heat, drought, alkalinity and poor soils limit human food supply.

In Southern California, many very old apple-cactus plants have become massive specimens. Along the coast they tend to grow larger overall, with thicker segments and more abundant branching. However, this vegetative prosperity is offset by the fact that the fruit tastes rather bland. Only in the blistering desert, as is the case in Israel, does the apple cactus reach its maximum sweetness.