A limited number of grapefruit and orange commercial cultivar budwood are available for growers, and some 30 varieties of dooryard, or non-commercial, cultivar budwood are available for the general public. For years, local nurseries and growers have routinely grafted, or tightly spliced, sweet citrus budwood onto hardier sour orange rootstocks to produce bountiful, healthy trees that do well here.
Most citrus grown in Texas is on sour orange rootstock.
CTV has killed millions of citrus trees on sour orange rootstock in other citrus-producing areas of the world. CTV has plagued citrus producers in California, Florida and Mexico, but only mild strains of the disease have been found among a few Lower Rio Grande Valley citrus trees, since no disease symptoms have been seen on CTV-infected trees. When enough of a particular commercial variety becomes available, the Texas Department of Agriculture will make it mandatory to obtain virus-free budwood only from the Citrus Center. Small numbers of specialty varieties, including Meyer lemon, tangerines, blood orange, pummelo, and satsuma budwood, imported from California's virus-free budwood program, are also available. Other research efforts to stave off CTV include chemical and biological control studies, cross-protection methods, and alternate rootstock studies.