example, in the home gardens of South and Southeast Asia. Before World War II, the majority of produce grown in the United States was heirlooms. In the 21st century, numerous community groups all over the world are working to preserve historic varieties to make a wide variety of fruits, vegetables, herbs, and flowers available again to the home gardener, by renovating old orchards, sourcing historic fruit varieties, engaging in seed swaps, and encouraging community participation. Requirements The definition and use of the word heirloom to describe plants is fiercely debated. One school of thought places an age or date point on the cultivars. For instance, one school says the cultivar must be over 100 years old, others 50 years, and others prefer the date of 1945, which marks the end of World War II and roughly the beginning of widespread hybrid use by growers and seed companies. Many gardeners consider 1951 to be the latest year a plant could have originated and still be called an heirloom, since that year marked the widespread introduction of the first hybrid varieties. It was in the 1970s that hybrid seeds began to proliferate in the commercial seed trade. Some heirloom varieties are much older; some are apparently pre-historic. Another way of defining heirloom cultivars is to use the definition of the word heirloom in its truest sense. Under this interpretation, a true heirloom is a cultivar that has been nurtured, selected, and handed down from one family member to another for many generations. Additionally, there is another category of cultivars that could be classified as "commercial heirlooms": cultivars that were introduced many generations ago and were of such merit that they have been saved, maintained and handed down—even if the seed company has gone out of business or otherwise dropped the line. Additionally, many old commercial releases have actually been family heirlooms that a seed company obtained and introduced. Regardless of a person's specific interpretation, most authorities agree that heirlooms, by definition, must be open-pollinated. They may also be open-pollinated varieties that were bred and stabilized using classic breeding practices. While there are no genetically modified tomatoes available for commercial or home use, it is generally agreed that no genetically modified organisms can be considered heirloom cultivars. Another important point of discussion is that without the ongoing growing and storage of heirloom plants, the seed companies and the government will control all seed