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Hugh A. Daubeny and Dana Stary

Abstract

Seedlings from 21 collections of the native North American red raspberry, Rubus idaeus strigosus (Michx.), were screened for reaction to Amphorophora agathonica Hottes, the aphid vector of the red raspberry mosaic virus complex. Sixty-four seedlings from 1,041 screened were selected for resistance to colonization. Three of these were intercrossed and also crossed with 2 cultivars of R, i. vulgatus Arrhen origin to produce F1 progenies. Inheritance of the resistance reaction in the 3 selected seedlings appeared to be controlled by 2 dominant complementary genes. These genes, which are designated Ag2 Ag3, do not appear to give as high a level of resistance to the aphid as gene Ag1, which is of R. i. vulgatus origin and gives virtual immunity. It is suggested that genotypes combining Ag, with Ag2 and Ag3 might be of value in reducing genetic vulnerability if virulent biotypes of A. agathonica appear. Screening for reaction to the aphid under laboratory conditions, prior to field planting, eliminated large numbers of susceptible seedlings. Additional screening in the field the year of planting eliminated more. Segregation ratios, which had been adjusted from the field results, gave better agreements than laboratory screenings alone to the proposed hypotheses.

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Alfred F. Trappey II, Charles E. Johnson, and Kristi Whitley

National demand for authentic Southern cuisine has contributed to the increased utilization of mayhaw fruit. Certain fruit characteristics are essential for the processing of mayhaw. Most of the mayhaw fruit used in processing comes from wild populations. Efforts are being made to identify superior clones from native populations. This study was undertaken to determine the chances of finding a superior clone with desirable processing attributes in a completely random population of mayhaw seedlings. Trees were removed from a 36 year-old mayhaw seedling orchard and relocated to a new orchard. The original orchard contained over 1500 trees. Five years after establishment in the new orchard, fruit were harvested from 75 of the trees and evaluated for fruit weight, percent malic acid, percent soluble solids, and color. Of the 75 trees, 48 were within one standard deviation of the mean trunk diameter. Seven trees fell below 12.1 cm and only 4 trees were larger than 19 cm. The mean fruit weight was 2.1 g with a range from 1.77-2.4 g. Sixty-seven percent of the trees produced fruit having weights within one standard deviation of the mean. Percent malic acid of mayhaw juice averaged 1.35% among the 75 trees. Seventy-two percent of the trees produced fruit with percent malic acid within one standard deviation of the mean. Mean percent soluble solids of mayhaw juice were 6.1 with a range of 5.36% to 7.01%. Seventy-three percent of the trees produced fruit with soluble solids percentages within one standard deviation of the mean. The probability of finding individuals in this population that exceeded the mean of these parameters (percent malic acid,%SS, and fruit weight) is less than 10%.

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Matthew D. Clark and Eric Watkins

Native grass species, when used as low-input turf, offer many benefits that could address concerns about water use, sustainability, and increased turf management operating expenses ( Diesburg et al., 1997 ). Low-maintenance turf often has lower

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Judson S. LeCompte, Amy N. Wright, Charlene M. LeBleu, and J. Raymond Kessler

al., 2000 ). Limited information is available on salt tolerance of woody landscape species native to the southeastern United States ( Jordan et al., 2001 ; Wu et al., 2001 ). Previous evaluation of salt tolerance of woody landscape plant species

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Jaime Molina-Ochoa*, Eva Judith Hueso-Guerrero, Roberto Lezama-Gutiérrez, Javier Farías-Larios, Francisco Radillo-Juárez, Abraham García-Berbe, and Jalil Fallad-Chávez

The agave weevil (Scyphophorus acupunctatus Gyllenhal) (AW) is widely distributed and is severe pest of plants in the Order Liliales, Familiy Agavaceae, such as Agave tequilana, A. fourcroydes, A. sisalana, A. sp., Polianthes tuberosa, and Yucca sp. Some of these species have importance as ornamental, medicinal, fragrant essence, and raw fiber. AW is controlled with insecticides, but insecticides are unable to reach the larvae in the galleries where the larvae borrows the agave crowns. Galleries are cryptic habitats where the entomopathogenic nematodes are able to infect instars of the AW. Recently, Hueso-Guerrero, and Molina-Ochoa (2004) reported the occurrence of native steinernematid nematodes naturally infecting the AW larvae. Virulence of isolates and strains of steinernematid and heterorhabditid nematodes against AW larvae was determined under laboratory conditions. Three native steinernematid isolates obtained from naturally infected AW larvae (A1, A2, and A3) were bioassayed a concentration of 100 nematodes/mL and petri dish (60 × 10 mm) arenas. Native isolates were isolated from AW larvae attacking agave crowns. Other strains evaluated were: S. carpocapsae All and Mexican, S. riobrave, and Heterorhabditis bacteriophora NC2. Native steinernematid isolates caused 100% mortality, however exotic strains caused mortality ranges between 90%, and 40%. Steinernema carpocapsae All strain, S. riobrave, H. bacteriophora NC2, and S. carpocapsae Mexican strains caused 90%, 60%, 50%, and 40% mortality, respectively. Results suggest that native steinernematid isolates, and S. carpocapsae All strain have potential as biological control agents against the AW weevil.

Open access

Lyn A. Gettys and Michael A. Schnelle

Conventional wisdom suggests that only introduced species can be invasive and that indigenous species cannot be classified as “weeds” because they belong in their native range. Therefore, most weed ecology and management research is focused on non-native

Open access

Orville C. Baldos, Aleta Corpuz, and Lindsey Watanabe

species possess a compact growing habit and have interesting leaf and stem coloration, research of the ornamental potential of these native species has been limited. Currently, Peperomia blanda is the only native Hawaiian species that is commercially

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Melody Reed Richards, Larry A. Rupp, Roger Kjelgren, and V. Philip Rasmussen

foliage ( Guilford and Smith, 1959 ; Iles and Vold, 2003 ) are also highly desirable. Native intermountain western United States deciduous tree species offer a potential pool of plants for ornamental landscape use, but assessing and selecting desirable

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Carlos Efraín Reyes-González, José Pablo Torres-Morán, Blanca Catalina Ramírez-Hernández, Liberato Portillo, Enrique Pimienta-Barrios, and Martha Isabel Torres-Morán

use and energy savings in extreme climates ( McFarland, 2017 ; Timur and Karaca, 2013 ; van den Berg and van den Berg, 2015 ), but there is a need to increase the set of native plants with potential to be used in green vertical structures and

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Julie Guckenberger Price, Amy N. Wright, Robert S. Boyd, and Kenneth M. Tilt

recommendations for using native plant species increase ( Southeast Exotic Pest Plants Council, n.d .), it is possible that this planting technique could be used to successfully establish native shrubs in a variety of landscapes. The objective of this study was to