This disclosure relates to a new and distinct variety (cultivar) of sweetpotato named ‘CX-1’.
This new variety of sweetpotato (Ipomoea batatas (L.) Lam.) was developed by selection of ‘Xushu 18’, and designated ‘CX-1.’ It was selected for large roots, very high dry matter content and higher yield. Field tests were conducted in Florida and South Carolina. Although there are a large number of sweetpotato varieties, there is a wide range of appearance, growth parameters, and uses, not a lot is known about the genetics of this crop species. Sweetpotato is the 7th largest food crop in the world and is a major food staple in many countries, mostly in the tropics.
Sweetpotatoes are underground storage roots, not tubers. The botanical description of a tuber is a short, thickened portion of an underground stem. The tuber has eyes composed of a ridge bearing a ‘scale-like’ leaf with tiny meristematic buds in the axial of this scale-like leaf. The sweetpotato is a true root, not an underground tuber that has buds. The anatomy of a storage root is the same as any root, with an additional ability to expand radially to store additional starch and nutrients. The sweetpotato crop is asexually propagated crop from ‘seed’ roots and plant cuttings.
Currently grown U.S. sweetpotato varieties were developed to be eaten as a highly nutritious and delectable vegetable. This variety type has been bred for specific traits for that use. They produce relatively uniform, attractively shaped storage roots, with dark orange flesh, a sweet, delicious flavor, and a moist texture (from 77% to 81% moisture). The typical size of these roots is from 6 to 16 ounces. The typical fresh weight yields of these varieties will range from 12 to 15 tons of marketable roots per acre.
The sweetpotato variety Xushu 18 is a variety that was publicly released in 1972 from China. It was bred by researchers in Jiangsu Province, China. Xushu 18 was a seedling from a cross from the variety Xindazi and breeding line 52-45. (Gitoner, C. 1996. Potato and Sweetpotato in China: systems, constraints, and potential. International Potato Center. Lima, Peru).
‘Xushu 18’ has been a popular variety in China, a country that is a major producer of sweetpotatoes. Researchers in China report that during several decades, dozens of new varieties derived by mutation from named varieties have been registered. Researchers in Xuzhou, China report that a single plant resulting from a selection of ‘Xushu 18’ with superior characteristics was named ‘Xu 77-6’ and was selected to replace normal ‘Xushu 18’ (Daifu, M., Hongmin, L., DaPeng, L., and Yi, W. 2000. Sweetpotato varieties decline in China and the present practices. International Workshop on Sweetpotato Decline Study Sep. 8-9 2000. Kyushu National Agricultural Experiment Station. Miyakonojo, Japan.)
‘Xushu 18’ was not developed as a table vegetable. It was developed for its production of starch and for animal feed. It is not sweet or delicious, but is white fleshed, very bland and very dry,—about 28% dry matter. Commercial yields in China have been reported from 6.88 ton up to 18.5 tons of fresh root weight per acre (Gitoner, 1996). Currently there are no sweetpotato varieties, with high dry matter content, commercially grown in the U.S. for industrial uses such as starch and ethanol.
Starting with the ‘Xushu 18’, a distinctive, new cultivar was selected and developed for large roots, high dry matter and higher total yield. The original ‘Xushu 18’ cultivar was obtained from the Plant Genetic Resourses Unit, USDA, ARS, Griffin, Ga. In Spring 2008 ‘CX-1’, was first asexually propagated as cuttings from a single plant selection of ‘Xushu 18’. At the test farm in Colleton County, S.C., a single plant was selected for very high yield and propagated there for multiple location testing. After years of field trials, it was determined that a selected high-yielding single plant of Xushu 18, named ‘CX-1’, produced a higher yield of sweetpotatoes with a higher dry matter content compared to published data on ‘Xushu 18’ (Table 1).
TABLE 1Fresh Fresh Weight inWeight inRoot DryResearcherLocationStatusTons/haTons/AMatter %Ma Daifu, China Virus 4017.829CIP(mean 19 Freelocations)uVirus 3415.228CheckGruneberg, PeruMean3013.625Crop SciTingo MariaHighest7031.5NRaLa MolinaLowest 5 2.2NRXie Yi Zhi, ThailandHighest2712.026ARCRyan-BohacUSAFL49.033‘CX-1’USASC37.533aNR is Not Reported;ha = hectors;A = acresWolfgang, G., Manrique, K., Zhang, D, and Hermann, M. 2005. Genotype X Environment interactions for a diverse set of sweetpotato clones evaluated across varying ecogeographic conditions in Peru. Crop Science. 45:2160-2171.Zhi, X. Y. Effect of Potassium on the yield of three sweet potato varieties. 1991. Asian Regional Vegetable Research Center. Proceedings of Training Workshop.Daifu, M., Hongmin, L., DaPeng, L., and Yi, W. 2000. Sweetpotato varieties decline in China and the prevent practices. International Workshop on Sweetpotato Decline Study Sep. 8-9, 2000. Kyushu National Agricultural Experiment Station. Miyakonojo, Japan.
Sweetpotato roots of ‘CX-1’ can be used to produce both starch and fuel ethanol. Estimates of at least 1500 gallons per acre of sweetpotatoes were based on field tonnage per acre, and on laboratory tests of the amount of ethanol produced per ton of dry matter from storage roots. Sweetpotato roots of ‘CX-1’ were also used to make chips and fries. The high dry-matter ‘CX-1’ roots are more suited to making chips and fries than those made from the sweet, watery-textured vegetable types of sweetpotato like the leading U.S. variety, ‘Beauregard’, (19-20% dry matter). The dry matter content of the ‘CX-1’ cultivar is at least 32%. In contrast, commercial vegetable type sweetpotatoes cultivars have a dry matter content that ranges from 19 to 23%. The texture of the ‘CX-1’ is dry and mealy in contrast to vegetable types that are moist and sweet with visible syrup in the flesh. The chips made from ‘CX-1’ were crisp, and light in color, similar to a commercial chip made from the white potato. (FIG. 5). Both the ‘CX-1’ chips and fries with high dry matter take up significantly less oil and were less bitter than these products made from the white potato.
When properly cured and stored at 50° to 60° F., the ‘CX-1’ variety can store up to one year. Long-term storage is a genetically controlled trait and a requirement for any successful cultivar in the temperate zones of agricultural production like the U.S. This is in contrast to typical tropical dry fleshed varieties that will deteriorate very quickly in storage. The asexual reproductions run true to the original sweetpotato and to each other in all respects.
Samples of the ‘CX-1’ variety will be deposited and maintained.