Tomato Breeding Project Fueled By Over 1,000 Backyard Gardeners In 2005, gardeners Craig LeHouiller and Patrina Nuske-Small created the Dwarf Tomato Project. They wanted to preserve the flavor and beauty of heirloom tomatoes, without taking up too much space. They started crossbreeding heirloom tomatoes with smaller dwarf tomato plants. To do so, they enlisted volunteers from all over the world. Over 1,000 people have participated so far. You can even buy the seeds and plant them in your own garden! Ira talks with the project’s co-founder, gardener and author, Craig LeHoullier, based in Hendersonville, North Carolina.   Southwestern States Break The Dam On Water Stalemate Southwestern states have been aware for decades that their use of Colorado River water is not sustainable. Forty million people depend on the watershed across seven states, several tribes, and northern Mexico. After intense pressure from the federal government, Arizona, California, and Nevada presented a plan last month to cut water use in these states. While the proposal isn’t final, it’s an important step in a long stalemate among southwestern states hesitant to use less water. The three states propose cutting 3 million acre-feet in water use through 2026—about ten percent of their total water allocation. The federal government plans to spend $1.2 billion to pay water users for the cuts. Joining Ira to break down what this plan means for southwest states is Dr. Sharon Megdal, director of the University of Arizona’s Water Resources Research Center in Tucson, and Luke Runyon, managing editor and reporter for KUNC, in Grand Junction, Colorado.   Tracking The Saguaro Cacti Decline One of the most iconic symbols of the American Southwest is the saguaro cactus—the big, towering cactus with branching arms. Saguaro are the most studied variety of cactus, yet there’s still much we don’t know about them. Once a decade, researchers from the University of Arizona survey plots of roughly 4,500 saguaro to assess the health of the species. This past year there was a record low number of new cacti growing—the fewest since they started decadal surveys in 1964. What’s driving this decline? Ira talks about the state of saguaro cacti with Peter Breslin, postdoctoral researcher at the University of Arizona’s Desert Laboratory on Tumamoc Hill, based in Tucson, Arizona.   These Conservation Scientists Are Keeping The Sonoran Desert Diverse Many Americans might be surprised just how expansive and diverse the Sonoran Desert actually is. The 100,000 square-mile desert stretches across the border between the U.S. and Mexico, with the northernmost regions in southern California and Arizona making up just one third of the desert. The sweeping terrain is home to thousands of plant and animal species and contains every existing biome in the world—from timber tundras to rolling grasslands to arid desert basins. The majority of the Sonoran is within the Baja California peninsula and the Mexican state of Sonora, which includes the Gulf of California. The gulf alone is teeming with life—famed ocean explorer Jacques Cousteau once called the desert, “the world’s aquarium.” Ira talks about the rich biodiversity of the Sonoran Desert and the importance of scientific collaboration across the border with Ben Wilder, director and co-founder of Next Generation Sonoran Desert Researchers, and Michelle María Early Capistrán, a conservation fellow at Stanford University and board member of the Next Generation of Sonoran Desert Researchers.   To stay updated on all-things-science, sign up for Science Friday's newsletters. Transcripts for each segment will be available the week after the show airs on sciencefriday.com.