Fruit Quality of New Cold-Hardy Opuntias from Northern and High-Elevation Sites in Mexico
Tolerance to freezing weather of about 12°C is the major biological barrier to commercial Opuntia fruit production in Texas. Since one of the most severe freezes killed all commercial cactus varieties to ground level in December 1989, three new germplasm collections with potential for increased cold hardiness were obtained at Texas A&M University-Kingsville. In the summer of 1998, these collections were 8-, 7-, and 5-growing-seasons old. Despite a record drought in the spring of 1998, for the first time many clones produced significant quantities of fruit. The fruit of these new clones was analyzed for fruit size, seed content, pH, and sugar content. A yellow-fruited spiny fruit (1402) and a spiny orange-fruited clone (1403) collected at 2200 m elevation near Saltillo, Mexico, had a good balance of yield and fruit quality and deserve further evaluation, especially for use in cold areas. Of the 29 clones in the selection program for survival at 16°C by Lorenzo Martinez Medina, clone 1436 had the greatest potential for production and total soluble solids (TSS). Two clones (1452 and 1458) obtained from a major collection trip in northern Mexico had promise. Clone 1452, a spineless red-fruited clone from a region where 16°C temperatures occurred, had good production of moderate TSS fruit (12.6), while clone 1458 had early production of high TSS (13.5) yellow fruit. Particular attention was paid to the seed content of the fruits because development of low-seedy varieties has been deemed an important priority for first-time consumers. Six new clones with potential for low seediness were identified. Two of these clones, a spineless yellow-fruited clone (1260) from Algeria and a spiny orange-fruited clone from Mexico (1403), had sufficient yield, fruit size, and TSS to have immediate commercial potential. The remaining clones with low seed contents (1391, 1267, 1414, and 1434) either had too small fruit size, too low yield, or too low TSS to be commercially acceptable. However, these latter clones have potential for use as parents in a breeding program.