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  • Author or Editor: J. W. Moyer x
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Abstract

‘Scarlet’ sweet potato [Ipomoea batatas (L.) Lam.], designated NCM-283 during testing, was released by the North Carolina Agricultural Research Service. ‘Scarlet’ is a dark-skinned sweet potato with orange flesh intended for growers and consumers desiring deep red to purple skin color. The major advantage of this cultivar over other red sweet potatoes is the greater intensity and stability of the dark skin color. The skin color is distinctly darker at harvest and more stable in storage than those of ‘Copper Skin Jewel’, the most widely grown red skin cultivar in North Carolina, and ‘Red Jewel’, a cultivar popular in other areas of the southeastern United States but not grown in North Carolina. Many characteristics of ‘Scarlet’ are similar to ‘Jewel’ (2); foliage growth habit, disease resistance, and insect resistance are all similar. However, ‘Scarlet’ has a distinct root shape and it scored significantly higher in baking trials.

Open Access
Authors: and

Abstract

‘Pope’ is a new cultivar of sweet potato [Ipomoea batatas (L.) Lam] developed at North Carolina State University that is high-yielding and early-maturing with high resistance to Fusarium wilt, root-knot nematodes, and flooding damage in the field. ‘Pope’ is named for Daniel T. Pope, who was the sweet potato breeder at North Carolina State University until his retirement in 1975.

Open Access

Fingerprinting using molecular markers is a highly effective method of cultivar identification that is a powerful aid to traditional methods based on morphology. Amplified fragment length polymorphism (AFLP) is a robust and reliable method for generating molecular markers that has been used to evaluate many crops for a variety of applications. In this study, AFLP was used to develop and validate robust genetic fingerprints for poinsettia (Euphorbia pulcherrima Willd. ex Klotzch) cultivars. Polymorphism selection was completed to facilitate the identification of useful polymorphisms and minimize future fingerprinting costs and time. Poinsettia is a highly variable crop subject to genetic drift and variable cultivars. Validation of polymorphisms to remove those associated with intracultivar variation improved the reliability of the fingerprinting. The result was a poinsettia AFLP database that defines the genetic fingerprints of 104 cultivars. Cluster analysis illustrated differentiation of most poinsettia cultivars tested. Selection of a subset of AFLP polymorphisms resulted in clustering of cultivars according to known origin and breeding program. This method has applications not only for cultivar identification for cultivar protection, and maintenance of cultivar uniformity, but also has the potential application of developing markers for important traits.

Free access

Abstract

‘White Delite’ is a moist-type, white-fleshed sweet potato [Ipomoea batatas (L.) Lam] developed at North Carolina State Univ. in 1979 and tested as NC1135. There is a consistent but limited demand for white-fleshed sweet potatoes. These types are certainly not as widely grown in the United States as orange-fleshed types and usually are confined to sales at local farmers’ markets or for planting in home gardens. Cultivars presently available have little disease resistance and poor yield potential. This cultivar provides a high-yielding, excellent quality white-fleshed cultivar for local markets and/or garden types.

Open Access

Abstract

‘Sweet Red’ is a moist-type sweet potato [Ipomoea batatas (L.)] developed at North Carolina State Univ. in 1976. It was evaluated as NC727 in regional yield trials by the National Sweet Potato Collaborator Group in 1981 (observational test), 1982, and 1983 (advanced tests). The release of ‘Sweet Red’ provides the industry with a high-yielding, high-quality, red-skinned sweet potato.

Open Access

The establishment of a sweet potato repository in Georgia that will eventually accept and distribute true seed of sweet potato [Ipomoea batatas (L.) Lam.] raised the question of seed transmission of viruses, especially of sweet potato feathery mottle virus (SPFMV). Seedlings obtained from virus-infected parent plants were free of viral infection. Examination of virus distribution in virus-infected plants determined that SPFMV was present in vegetative tissue, but not in reproductive organs, indicating that the probability of SPFMV transmission in sweet potato through seed is very low.

Free access

Fluorescent amplified fragment length polymorphism (F-AFLP) and microsatellites (SSRs) were used to evaluate new guinea impatiens (Impatiens hawkeri W. Bull) cultivars. Ninety-five quality-selected polymorphic fragments from 10 F-AFLP+3 primer combinations were used to evaluate 100 cultivars representing a variety of colors, forms, and breeding programs. Jaccard similarities and unweighted pair-group method of the arithmetic average (UPGMA) clustering formed a dendrogram with three cultivar groups, to a large extent clustering the cultivars by breeder with a high cophenetic correlation coefficient. A small insert genomic library was created and 442 kb of new guinea impatiens sequence was screened for repetitive motifs, resulting in 14 microsatellite markers. A subset of 46 cultivars representing five commercial breeding companies and 11 cultivar series was selected for microsatellite analysis. Seven loci were polymorphic, with two to six alleles per locus. Although both methods were equally effective in distinguishing the cultivars from one another, the topologies of the dendrograms for the two methods were different. The topology of the AFLP dendrogram reflected possible relationships based on cultivar series and breeding company, while the SSR dendrogram did not. The objectives of this research were to develop and validate both F-AFLP and SSR methodologies for new guinea impatiens, identify markers that can be reliably used for fingerprinting, and create a database for future cultivar comparisons.

Free access

Abstract

‘Carolina Nugget’ (Fig. 1) is a moist sweet potato developed at N.C. State Univ. in 1954. In 1957 and 1958, it was tested throughout North Carolina in regional tests as the experimental clone NC 172. Although it never has been released officially as a cultivar, it has been grown for commercial use in several southern states under many different names (e.g., Red Nugget, Carolina Nugget, Golden Nugget). The formal release and naming of this sweet potato cultivar should alleviate the confusion that has occurred when growers market or buy plant material.

Open Access

When sweetpotato chlorotic stunt crinivirus (SPCSV) and sweetpotato feathery mottle potyvirus (SPFMV) infect sweetpotato [Ipomoea batatas (L.) Lam.], they interact synergistically and cause sweetpotato virus disease (SPVD), a major constraint to food productivity in east Africa. The genetic basis of resistance to these diseases was investigated in 15 sweetpotato diallel families (1352 genotypes) in Uganda, and in two families of the same diallel at the International Potato Center (CIP), Lima, Peru. Graft inoculation with SPCSV and SPFMV resulted in severe SPVD symptoms in all the families in Uganda. The distribution of SPVD scores was skewed toward highly susceptible categories (SPVD scores 4 and 5), eliminating almost all the resistant genotypes (scores 1 and 2). Likewise, when two promising diallel families (`Tanzania' × `Bikilamaliya' and `Tanzania' × `Wagabolige') were graft inoculated with SPCSV and SPFMV at CIP, severe SPVD was observed in most of the progenies. Individual inoculation of these two families with SPCSV or SPFMV, and Mendelian segregation analysis for resistant vs. susceptible categories led us to hypothesize that resistance to SPCSV and SPFMV was conditioned by two separate recessive genes inherited in a hexasomic or tetradisomic manner. Subsequent molecular marker studies yielded two genetic markers associated with resistance to SPCSV and SPFMV. The AFLP and RAPD markers linked to SPCSV and SPFMV resistance explained 70% and 72% of the variation in resistance, respectively. We propose naming these genes as spcsv1 and spfmv1. Our results also suggest that, in the presence of both of these viruses, additional genes mediate oligogenic or multigenic horizontal (quantitative) effects in the progenies studied for resistance to SPVD.

Free access