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T.E. Morelock, J.C. Correll, and L.P. Brandenberger

Downy mildew (Blue mold) is probably the most common spinach disease in most parts of the world, and it can be a problem in the mid-South. Frequently, other diseases such as white rust and fusarium cause major crop loss. The Arkansas breeding program was initiated 25 years ago to address white rust and fusarium, as well as other diseases that destroy spinach crops. Since single gene resistance is not available for most spinach diseases, it was necessary to utilize polygenic resistance to develop varieties that are resistant to most of the common spinach diseases that occur in the Arkansas River Valley of Arkansas and Oklahoma. Highly resistant genotypes have been developed by using disease nurseries and field screening, so frequent selections are made based on the reaction to 3-4 diseases.

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T.E. Morelock, D.R. Motes, and A.R. Gonzalez

Southernpeas (Vigna ungurculata) are a popular crop in the southeastern United States. They are an important crop to Arkansas processors, market gardeners, and home gardeners. While the bulk of the acreage produced in the state is pinkeye purple hull types, there is a demand for other horticultural types. At present, there is not a well-adapted blackeye that is available to producers in the state. For that reason, Arkansas Blackeye #1 is being released. Arkansas Blackeye #1 has been widely tested under the designation Arkansas 91-245. It produces a medium-sized bush plant that is well suited to conventional or narrow row spacing and matures 2 to 3 days earlier than Coronet under Arkansas conditions. Arkansas Blackeye #1 produces yield similar to the best pinkeye purple hull types. Samples have been canned by the Food Science Dept. at the Univ. of Arkansas and the canned samples have compared favorably to the industry standards.

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T.E. Morelock, D.R. Motes, and A.R. Gonzalez

Southernpea (cowpea), Vigna ungiculata L. Walp, is an important processing and fresh-market vegetable in the southern United States. While many of the newer varieties are early maturing, there is still a need for late-maturing, high-yielding varieties. Arkansas 92-552 fills this niche. It is a bush plant that produces silver pods in the upper portion of large plants that are free of basal runners. The seed are medium size with a bright pink eye. Maturity is 5 to 7 days later than `Coronet' under Arkansas conditions. The variety processes well and canned peas have been rated equal to `Coronet' by consumers panels. The yield potential is high and it has produced higher yield than `Coronet' in replicated trials in Arkansas. 92-552 is also resistant to rootknot nematode.

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J.A. Kirkpatrick, J.B. Murphy, and T.E. Morelock

Interest in the health benefits of vegetables prompted an investigation of the levels of carotenoids in commercial varieties and UA breeding lines of spinach. Plant carotenoids perform a critical function as antioxidants, providing protection against a variety of reactive oxygen species generated primarily during photosynthesis. When ingested by humans, these compounds maintain their antioxidant activities and are receiving considerable attention in relation to multiple health benefits, including cancer prevention. While the best-known and most-studied carotenoid is beta-carotene, other carotenoids are now receiving attention due to their higher antioxidant activity compared to beta-carotene. Most dark-green leafy vegetables, such as spinach and kale, are relatively high in carotenoids, especially lutein. In this study, significant differences in average content of both lutein and beta-carotene were found between genetic lines of spinach. Some lines exhibited considerable variation between plants, while others were highly uniform. There was a very high correlation (r 2 = 0.96) between lutein content and betacarotene content. The significant difference between spinach lines suggests that improvement of general carotenoid antioxidants and lutein could be obtained through a breeding program.

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Justin Butcher, T.E. Morelock, and D.R. Williams

Fresh-shelled southernpeas [Vignaunguiculata(L.) Walp.] is a popular vegetable. Postharvest storage of fresh-shelled peas is a crucial step in the production process. Farmers strive to produce a product that is high in quality and freshness with appropriate texture and appealing color. Improper storage and handling of southernpeas will result in deterioration. In an effort to prevent potential losses of southernpeas, this study was conducted to determine the best method to ship and store shelled peas. Five southernpea varieties: `Early Acre', `Early Scarlet', `Excel Select', `Coronet', and `Arkansas Blackeye #1' were planted in a randomized block design at the University of Arkansas. Twelve mature green pods of each variety were subjected to a sweated and unsweated treatment and then shelled. After shelling, seed were subjected to four different environmental conditions, and each treatment was evaluated for changes in physical appearance. Objectives of the study were to determine the best variety and environmental condition to maintain a quality marketable product. The study showed that a refrigerated environment at or near 3 to 5 °C allowed the crop to be stored for up to 2 weeks. It also appeared that sweating assisted with the shelling process and maintained appearance of each variety longer.

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L.P. Brandenberger, T.E. Morelock, and J.C. Correll

Spinach germplasm (707 accessions) from collections from six countries were screened for resistance to race 4 of the downy mildew pathogen Peronospora farinosa f. sp. spinaciae; these collections contained germplasm that originated from 41 countries. The predominant species examined was Spinacia oleracea L., however, eight accessions of S. turkestanica Iljin and two accessions of S. tetrandra Stev. were also tested. About 40 seedlings of each accession were inoculated. The cultivar St. Helens was included as a susceptible control in each test. The majority of accessions tested (>98%) were susceptible to race 4. Nine accessions exhibited some resistance to race 4 (9% to 38% of the seedlings within an accession were resistant), and two accessions, CGNO 9546 and SPI 82/87, exhibited a high level of resistance (60% and 80% resistant, respectively). Resistance identified in several of the accessions in this study may be useful for breeding for race 4 resistance.

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Hallie G. Dodson, J.B. Murphy, and T.E. Morelock

Anthocyanins are naturally occurring plant pigments that are classified as flavonoids. Anthocyanins have important antioxidant properties which may help in prevention of cancer, arthritis, and cardiovascular disease. Finding common sources and possibly increasing levels of anthocyanins in food could be important to human health. This research project determined amount and type of anthocyanins in 16 cultivars and breeding lines of cowpeas (Vigna unguiculata). The information obtained from this research project will be used to improve anthocyanin content of cowpeas by breeding. Of the 16 cultivars and breeding lines, only a black cowpea breeding line, 95-356, contained measurable levels of 3 types of anthocyanins: delphinidin, peonidin, and an unknown anthocyanin. Total anthocyanin content was 0.00242 mg·g–1, which is equal to 0.21 mg per ½-cup serving. In another study with 95-356 Rabi A. Musah, found a total anthocyanin content of 121.26 mg per serving and also found three other types of anthocyanins. The difference in the studies could be explained by the storage time of two weeks after the anthocyanins were extracted, but before they were eluded in this study. Additional studies are needed to determine if cowpeas can provide anthocyanin levels comparable to other fruits and vegetables.

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J.M. Al-Khayri, F.H. Huang, T.E. Morelock, and H.T. Zhang

The objective of this study was to determine the efficacy of Agrobacterium tumefaciens in transforming spinach (Spinacia oleracea L.) callus. Callus was induced from leaf disks of `Baker' on Murashige and Skoog (MS) medium supplemented with 2 mg L-1 kinetin and 0.5 mg L-1 2,4-D. Callus was cut into 2-mm pieces, and 0.5 g of callus was placed in each 250-ml flask which contained 20 ml of MS liquid medium. The suspension cultures were inoculated with 100 μl of an overnight culture of A. tumefaciens harboring pMON 9749 (provided by S. Rogers, Monsanto Co., St. Louis), a plasmid cointegrated with kanamycin resistance and β -glucuronidase (GUS) genes. After coculturing for 2 days at 22C with shaking at 100 rpm, the medium was replaced with selection medium containing (in μg/ml) 75 kanamycin, 100 cefotaxime, and 200 carbenicillin and maintained for 3 weeks. Transient expression of GUS gene in transformed cells was detected with X-glu assay. This method resulted in a high level of transformation and provides the first report of transformation in spinach. This study was funded by a grant (92-B-32) from the Arkansas Science & Technology Authority.

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J.M. Al-Khayri, F.H. Huang, T.E. Morelock, and T.A. Busharar

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T.E. Morelock, J.L. Bowers, D.R. Davis, and D.R. Motes

Southernpeas are an important crop to Arkansas processors, market gardeners and home gardeners. While the bulk of the acreage produced in the state is pinkeye purple hull types, there is a demand for other horticultural types. At present some processors consider `White Acre' to be the standard of cream pea quality, but under Arkansas conditions, `White Acre' produces excessive vine growth, is very late to mature and is susceptible to bacterial blight. For these reasons, the Arkansas Agricultural Experiment Station announces the release of `Early Acre'. `Early Acre' has been widely tested under the designation Arkansas 84-154 and produces a very compact bush plant that has seed similar in size and shape to `White Acre', but matures 8-10 days earlier under Arkansas conditions. Although the plant type is well suited to narrow row spacing, `Early Acre' has produced yields similar to `White Acre' when both are planted at conventional row spacings. Samples have been canned by the Dept. of Food Science at the University of Arkansas and the samples have been rated equal to `White Acre' in processed quality. “Early Acre' has exhibited high levels of resistance to bacterial blight in replicated yield trials under field epidemics in both Arkansas and Texas.