Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: J. Powell Smith x
Clear All Modify Search
Free access

Mark W. Farnham, Glen Ruttencutter, J. Powell Smith and Anthony P. Keinath

Collard (Brassica oleracea L. Acephala Group) is a leafy green vegetable adapted to the southeastern United States. The number of commercially available collard cultivars is limited, and the most popular cultivars are susceptible to fusarium yellows, a disease that most cabbage (B. oleracea Capitata group) cultivars are resistant to. We hypothesized that hybrids of cabbage and collard would look more like collard, because heading of cabbage is at least partially recessive to the nonheading growth habit of collard. We also postulated that cabbage–collard hybrids might be used directly as collard cultivars. To test these postulates, cytoplasmic male sterile cabbage inbreds were crossed to different male fertile collard inbreds and hybrid seed was produced. Resulting cabbage–collard hybrids were compared to conventional collard cultivars in three replicated field trials in South Carolina. In all trials, cabbage–collard hybrids exhibited size and weight more similar to conventional collard than cabbage, and throughout most of the growing season the collards remained nonheading. In addition, the cabbage–collard hybrids were much more uniform than open-pollinated collard cultivars. Among cabbage–collard hybrids there was significant variation with some hybrids appearing more collard-like than others. The collard inbreds designated A and B may have the greatest potential for making promising cabbage–collard hybrids. Particular hybrids (i.e., A3 or B2), derived from these inbreds and tested in this study, can perform better than certain conventional collards and may serve as possible new cultivars of this vegetable crop.

Free access

Howard F. Harrison Jr., D. Michael Jackson, Judy A. Thies, Richard L. Fery and J. Powell Smith

Restricted access

W. Patrick Wechter, Melanie M. McMillan, Anthony P. Keinath, J. Powell Smith and Mark W. Farnham

Free access

W. Patrick Wechter, Mark W. Farnham, J. Powell Smith and Anthony P. Keinath

Brassica leafy greens (Brassica juncea L. and Brassica rapa L.) represent one of the most economically important vegetable crop groups in the southeastern United States. In the last 10 years, numerous occurrences of a leaf-spot disease on these leafy vegetables have been reported in several states. This disease, known as peppery leaf spot, is now causing serious crop losses and has been attributed to the bacterial phytopathogen Pseudomonas syringae pv. maculicola (Psm). To date, it appears that all cultivars of the Brassica leafy greens are susceptible, and available pesticides for control of this disease appear unable to reduce the disease to acceptable levels. Thus, we undertook a search for potential resistance to this disease among accessions of B. juncea and B. rapa included in the U.S. Plant Introduction (PI) collection. In greenhouse trials, we screened commercial cultivars and 672 U.S. PIs (226 B. juncea and 446 B. rapa) for resistance to Psm with artificial inoculation. Although severity of disease symptoms was significantly different among inoculated accessions, no acceptable levels of resistance were found in any of the more than 400 B. rapa accessions tested. Only two B. juncea accessions (PI 195553 and G 30988) of 226 tested had acceptable levels of resistance that might prove economically useful.

Free access

Howard F. Harrison, Judy A. Thies, Richard L. Fery and J. Powell Smith

A preliminary screening experiment was conducted to evaluate 47 cowpea [Vigna unguiculata (L.) Walp.] genotypes for use as a weed-suppressing cover crop. Of these, 11 were selected for further testing on the basis of vigorous growth and weed-suppressing ability. In a field experiment repeated over 4 years, the selected genotypes were not different from the leading cover crop cultivar `Iron Clay' in biomass production. Vigor ratings, vine growth ratings, and canopy widths of some genotypes exceeded those of `Iron Clay' Vigor ratings and canopy measurements were efficient selection criteria that could be useful for breeding cover crop cowpea cultivars. All except one selection were highly resistant to southern root knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood], and the selections varied in seed size, photoperiod, and response to foliar diseases.

Free access

Howard F. Harrison, Judy A. Thies, Richard L. Fery and J. Powell Smith

A preliminary screening experiment was conducted to evaluate 47 cowpea [Vigna unguiculata, (L.) Walp.] genotypes for use as a weed-suppressing cover crop. Lines evaluated in this study included forage varieties, PI accessions, experimental breeding lines, and land races of unknown origin. Of these, 11 were selected for further testing on the basis of vigorous growth and weed-suppressing ability. In a field experiment repeated over 4 years, the selected genotypes were not different from the leading cover crop cultivar, `Iron Clay', in biomass production. Vigor ratings, vine growth ratings, and canopy widths of some genotypes exceeded those of `Iron Clay'. Vigor ratings and canopy measurements were efficient selection criteria that could be useful for breeding cover crop cowpea cultivars. All selections except an African cultivar, `Lalita', were highly resistant to southern root knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood], and the genotypes varied in seed size, photoperiod, and response to diseases.