Search Results

You are looking at 1 - 10 of 16 items for

  • Author or Editor: Arthur Q. Villordon x
  • Refine by Access: User-accessible Content x
Clear All Modify Search
Free access

Arthur Q. Villordon and Don R. LaBonte

Clonal propagation assures the maintenance of genetic purity of a sweetpotato variety. The existence of foundation seed programs further contributes to the conservation of favorable genetic constitution in a commercial cultivar. However, the improvement of current maintenance procedures is necessary as shown by the occurrence of mutations and the decline of certain commercial varieties. Information on the nature and extent of changes in sweetpotato would therefore be useful in this regard.

`Jewel' clones obtained from eight state foundation seed programs were subjected to yield tests and a RAPD-based assay. Differences in nearly all yield grades were detected during the 1991, 1992, and 1993 seasons. The yield of U.S. No. 1 grade roots varied from 27% to 46%. The quality factors measured also varied: % alcohol insoluble solids varied by 13%, while sucrose ranged from 9.6% to 19%. Total DNA was extracted from each clone and assayed against 40 primers. All primers produced amplified fragments. A total of 110 reproducible bands was generated by 38 primers. Putative polymorphic markers were scored in 21 (18.58%) of these bands based on the presence or absence of amplified products. The results suggest an underlying cause for the variability observed in phenotypic traits within sweetpotato clones.

Free access

Arthur Q. Villordon and Don R. LaBonte

Our research examined whether plants originating from adventitious sprouts from fleshy sweetpotato roots are genetically more variable than plants that arise from pre-existing meristematic regions, i.e., nodes. Our study compared one plant each of `Jewel', `Sumor', and L87-95 clonally propagated for seven generations both nodally and through adventitious sprouts. PCR-based analysis of 60 samples (10 nodal and 10 adventitiously derived plants/genotype) showed 20% polymorphism among adventitious materials vs. 6% among nodally derived plants. An “analysis of molecular variance” showed that differences between propagation methods accounted for 30% of the total marker variability. Our results support previous findings that, relative to non-meristematic materials, meristematic regions strictly control cell division and DNA synthesis that exclude DNA duplication and other irregularities.

Free access

Arthur Q. Villordon and Don R. LaBonte

Genetic uniformity was assessed among sweetpotato (Ipomoea batatas) clones propagated through adventitious and nodal procedures. A single sprout each of `Jewel,' `Sumor,' and L87-95 was used as source of clonal plants that were simultaneously propagated through conventional adventitious procedures and a tissue culture-based nodal culture technique. A sample of 15 decamer primers generated 64 scorable amplified fragments in a PCR-based assay, 29 of which were putatively polymorphic across n = 60 samples (10 each of nodal and adventitiously derived plants/genotype). Within adventitiously derived materials, putative polymorphisms ranged from 4.7% to 31.3% depending on the genotypic class. In contrast, putative polymorphisms ranged from 0.0% to 3.1% among nodally derived samples. Marker loci differentiated genotypes as well as putative marker phenotype variants through a multidimensional scaling analysis of the genetic similarity matrix. An `analysis of molecular variance' shows that genotypic effects accounted for 88.7% of the total molecular marker variability, while propagation effects (within genotypic groups) accounted for 11.3%. Results confirm that clonal plants derived from preexisting meristematic regions are more genetically uniform than plants propagated from adventitious origins.

Free access

Arthur Q. Villordon and Don R. LaBonte

Polymorphism analysis and yield tests were conducted among `Jewel' sweetpotato clones [Ipomoea batatas (L.) Lam] obtained from eight state foundation seed programs. Initially, 38 arbitrary primers generated a total of 110 scorable DNA fragments in a sample of virus-indexed plants from each clone source. The number of marker loci scored for each primer varied from one to eight with an average of 2.89. Twenty-one bands (19.1%) were scored as putative polymorphic markers based on the presence or absence of amplified products. Further estimation of variability within each clone source was accomplished by an assay of 10 sample plants per clone group by 14 marker loci generated by four selected primers. Polymorphic bands ranged from 7.1% to 35.7 % in five of eight clone groups. Field studies show variation in nearly all yield grades measured. In three tests during the 1991 and 1992 seasons, yield differences ranged from 27% to 46% within the economically important U.S. no. 1 root grade. The results suggest the usefulness of arbitrarily-primed markers in detecting intra-clonal sweetpotato DNA polymorphisms and indicate an underlying genetic cause for phenotypic variability in the crop.

Free access

Edward W. Bush, Don R. LaBonte, Ann L. Gray, and Arthur Q. Villordon

Production of disease-free sweetpotato [Ipomoea batatas (L.) Lam.] transplants is of major importance to certified and foundation seed programs and producers. Sweetpotato roots are traditionally planted and cuttings are harvested from propagation beds. The objective of this study was to investigate the efficiency of producing cuttings in nursery containers. Virus-tested and virus-infected `Beauregard' sweetpotato transplants were harvested from planting beds for the purpose of producing cuttings for transplants. Cuttings were established in 3.7-L plastic nursery containers filled with 100% pine bark amended with either low, medium, or high rates of Osmocote 14-14-14 and dolomitic lime. Resulting transplants produced a greater number of cuttings and greater plant biomass with higher fertilizer rates. Increasing fertilizer rates also had a positive effect on cutting production and biomass. Dry weight and stem growth were similar for both virus-infected and virus-tested transplants following first and second harvests. Producing foundation cuttings in nursery containers filled with a pine bark medium proved to be an efficient method of increasing virus-tested sweetpotato cuttings.

Free access

Don R. La Bonte, Paul W. Wilson, Arthur Q. Villordon, and Christopher A. Clark

‘Evangeline’ sweetpotato [Ipomoea batatas (L.) Lam.] was developed by the Louisiana Agricultural Experiment Station to provide a cultivar with characteristics similar to those of ‘Beauregard’ but with southern root-knot nematode resistance and higher sucrose content. ‘Evangeline’ produces acceptable numbers of uniform plants (sprouts) comparable to ‘Beauregard’. Days to harvest for ‘Evangeline’ and ‘Beauregard’ are similar; however, ‘Evangeline’ tends to produce fewer oversized or jumbo grade roots. ‘Evangeline’ appears widely adapted and particularly valuable in soils infested with southern root-knot nematode.

Origin

Initially identified and evaluated as L 99-35, ‘Evangeline’ originated in 1999 as a seedling from a polycross

Free access

Don R. La Bonte, Christopher A. Clark, Tara P. Smith, and Arthur Q. Villordon

‘Orleans’ sweetpotato [Ipomoea batatas (L.) Lam.] was developed by the Louisiana Agricultural Experiment Station to provide an orange-fleshed, light rose-skinned cultivar similar to ‘Beauregard’ (Rolston et al., 1987) with superior storage root shape and disease resistance similar to ‘Beauregard’. ‘Orleans’ produces excellent numbers of uniform plants. Days to harvest for ‘Orleans’ and ‘Beauregard’ are similar in the Gulf South production region. ‘Orleans’ in North Carolina appears competitive with other commercial cultivars; however, roots of ‘Orleans’ are too long in California to warrant production. The roots are elliptical and consistent in shape in varied soil types outside

Full access

Christopher A. Clark, Tara P. Smith, Donald M. Ferrin, and Arthur Q. Villordon

Because sweetpotato (Ipomoea batatas) is vegetatively propagated, viruses and mutations can accumulate readily, which can lead to cultivar decline. Sweetpotato foundation seed programs in the United States maintain the integrity of commercial seed stock by providing virus-tested (VT) foundation seed to commercial producers. A survey was conducted in Louisiana from 2007 to 2009 to examine the performance and quality of the foundation seed after it had been integrated into commercial sweetpotato operations. G1 seed [grown 1 year after virus therapy in the foundation seed production field at the Sweet Potato Research Station, Louisiana State University Agricultural Center (LSU AgCenter), at Chase, LA] was used as a reference to compare the yield and virus incidence of growers' generation 2 (G2) and generation 3 (G3) seed roots (grown in the growers' seed production fields 1 or 2 years following the year of foundation seed production). Although yields of plants grown from G2 and G3 seed were 86.3% and 86.1% for U.S. No. 1 and 83.3% and 86.0% for total marketable, respectively, compared with the yields from G1 seed, they were not significantly different. Yield and virus incidence data suggest that seed quality may vary from year to year and from location to location. Results from this study suggest that producers are realizing yield benefits by incorporating VT foundation seed into their production schemes, but further benefits could be attained if ways to reduce re-infection with viruses can be found.

Free access

Don R. La Bonte, Arthur Q. Villordon, Christopher A. Clark, Paul W. Wilson, and C. Scott Stoddard

‘Murasaki-29’ sweetpotato [Ipomoea batatas (L.) Lam.] was developed by the Louisiana Agricultural Experiment Station to provide a specialty-type white flesh, dark purple skin cultivar with southern root-knot nematode and soil rot resistance. ‘Murasaki-29’ produces excellent numbers of uniform plants (sprouts) early in the production season. ‘Murasaki-29’ matures later than ‘Beauregard’ in Louisiana. The roots in Louisiana can be elliptical, but often are round and sometimes splits occur. Production for fresh market is not anticipated in Louisiana as a result of its inconsistent appearance. In California, yields are competitive with other specialty white flesh types. Broad-spectrum disease resistance, including

Free access

Don R. La Bonte, Christopher A. Clark, Tara P. Smith, Arthur Q. Villordon, and C. Scott Stoddard

‘Bellevue’ sweetpotato [Ipomoea batatas (L.) Lam.] was developed by the Louisiana Agricultural Experiment Station to provide an orange-fleshed, copper-skinned cultivar with superior storage root shape, skin smoothness, disease resistance, and southern root-knot nematode resistance. ‘Bellevue’ is weak in production beds, although adequate plant numbers can be achieved with proper presprouting. ‘Bellevue’ can be harvested up to 10 days earlier than the ‘Covington’ (Yencho et al., 2008) in the California production region. ‘Bellevue’ and ‘Beauregard’ (Rolston et al., 1987) are similar in harvest days in the Gulf South production region. The roots are elliptical and