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Katie L. Dylewski, Amy N. Wright, Kenneth M. Tilt, and Charlene LeBleu

irrigation during a rain event and, as a result, may remain dry for a period of weeks until the next rain event regardless of soil type. Native plants adapted to low wetland areas are desirable for rain gardens because they are low maintenance, not invasive

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Roger Kjelgren, Lixue Wang, and Daryl Joyce

-water landscapes with variable soil and water conditions. Australia has an abundance of seemingly drought-tolerant native wildflower species in its vast interior arid zones. Many of these species have desirable ornamental qualities and apparent drought tolerance

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Chi M. Do, Kate L. Delaporte, Vinay Pagay, and Carolyn J. Schultz

sp.) ( Jacobsen et al., 2012 ). One crop plant that has not yet been assessed for salinity tolerance is Kunzea pomifera (muntries; Myrtaceae), one of 13 key Australian native food crops ( Clarke, 2013 ; Do et al., 2017 ; Sultanbawa, 2016 ). K

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Yuanwen Teng, Kenji Tanabe, Fumio Tamura, and Akihiro Itai

A total of 118 Pyrus sp. (pear) and cultivars native mainly to east Asia were subjected to randomly amplified polymorphic DNA (RAPD) analysis to evaluate genetic variation and relationships among the accessions. Two hundred fifty RAPD markers were scored from 20 decamer primers. RAPD markers specific to species were identified. Clustering analysis revealed two divisions: one comprising cultivars of P. communis L., and the other including all accessions of Pyrus native to east Asia. The grouping of the species and cultivars by RAPD data largely agrees with morphological pear taxonomy. However, some noted incongruence existed between two classification methods. Pyrus calleryana Dcne. clustered together with P. koehnei Schneid., P. fauriei Schneid. and P. dimorphophylla Makino. Pyrus betulaefolia Bge. clustered with P. ×hopeiensis Yu and P. ×phaeocarpa Rehd. A noncultivated clone of P. aromatica Kikuchi et Nakai grouped with P. aromatica cultivars. Pyrus hondoensis Nakai et Kikuchi and cultivars of P. ussuriensis Max. formed a single group. Some accessions from Korea (named Korean pear) had species-specific RAPD markers and comprised an independent group. Most of the Chinese white pears clustered together with most of the Chinese sand pears. Based on the present results, the new nomenclature P. pyrifolia var. sinensis (Lindley) Teng et Tanabe for Chinese white pear was suggested. Most accessions of Japanese pears fell into one main group, whereas pear cultivars from Kochi Prefecture of Japan subclustered with some Chinese sand pears and one accession from Korea. Our results infer that some local Japanese pear cultivar populations may have been derived from cultivars native to Kochi Prefecture in Shikoku region, and that the latter may have been introduced from ancient China and/or Korea.

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Thomas M. Gradziel and Dale E. Kester

Breeding lines have been developed incorporating introgressed genes from three native almond species Prunus fenzliana, Prunus webbii and Prunus argentea. Selected traits include self-fertility and autogamy, late bloom, smaller tree size, early nut maturity, improved cropping potential, and a well-sealed shell (endocarp) with high kernel/shell crack-out percentages. Fertility barriers, while present were easily overcome though linkage to introgressed genes with undesirable phenotypes remains an important obstacle to commercial use. Current breeding results, however, support a general conclusion that the wide diversity present within the range of species related to the cultivated almond (Prunus dulcis) provides an valuable gene pool for variety improvement.

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Anthony P. Keinath

Didymella bryoniae (Auersw.) Rehm [anamorph Phoma cucurbitacearum (Fr.) Sacc.], the plant pathogenic fungus that causes gummy stem blight and black rot on cucurbits, was first described in 1869 from Bryonia (bryony or wild hops) in central Europe. Today, this pathogen is found on six continents on at least 12 genera and 23 species of cucurbits. How did D. bryoniae progress from a pathogen of a native plant in central Europe to a worldwide threat to cucurbits cultivated in humid environments? Clues from the early discoveries of this fungus, its characteristics as a seedborne pathogen, and its broad adaptation to cucurbit hosts will provide some answers to this question.

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P. M. Lyrene and W. B. Sherman

Abstract

Date of 50% anthesis, date of 50% fruit ripening, length of fruit development period, fruit size, flavor, scar and color were determined for random samples of V. darrowi Camp, V. elliottii (Chapm.) Small, V. fuscatum Ait., and V. myrsinites Lam. growing in their native habitats in Alachua County, Florida. Mean berry weight ranged from 25.1 eg for V. fuscatum to 17.8 eg for V. myrsinites. V. elliottii flowered and ripened early, with only 60 days from flowering to ripening for 5 plants. V. myrsinites and V. darrowi flowered late, about 1 to 2 weeks after commercial V. ashei Reade, but ripened with V. ashei. Fruit ranged from shiny black to moderately glaucous for V. elliottii and V. darrowi but was black for V. fuscatum and V. myrsinites. Variance analysis suggested that selecting the best clone within a species is almost as important as selecting the best species in breeding most traits.

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Suleiman S. Bughrara, David R. Smitley, and David Cappaert

Six grass species representing vegetative and seeded types of native, warm-season and cool-season grasses, and pennsylvania sedge (Carex pensylvanica) were evaluated in the greenhouse for resistance to root-feeding grubs of european chafer (Rhizotrogus majalis). Potted bermudagrass (Cynodon dactylon), buffalograss (Buchlöe dactyloides), zoysiagrass (Zoysia japonica), indiangrass (Sorghastrum nutans), little bluestem (Schizachyrium scoparium), tall fescue (Festuca arundinacea), and pennsylvania sedge grown in a greenhouse were infested at the root zone with 84 grubs per 0.1 m2 or 182 grubs per 0.1 m2. The effects on plant growth, root loss, survival, and weight gain of grubs were determined. Survival rates were similar for low and high grub densities. With comparable densities of grubs, root loss tended to be proportionately less in zoysiagrass and bermudagrass than in other species. European chafer grubs caused greater root loss at higher densities. Grub weight gain and percentage recovery decreased with increasing grub density, suggesting a food limitation even though root systems were not completely devoured. Bermudagrass root weight showed greater tolerance to european chafer grubs; another mechanism is likely involved for zoysiagrass. Variation in susceptibility of plant species to european chafer suggests that differences in the ability of the plants to withstand grub feeding damage may be amenable to improvement by plant selection and breeding.

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Su-Young Hong, Kwang-Soo Cho, Ki-Oug Yoo, Jong-Taek Suh, and Dong-Lim Yoo

There are 25 species of aster in Korea. There is a controversy about the taxonomical classification of Aster. The genus Aster was classified into four genera, Aster, Gymnaster, Kalimeris, and Heteropappus, by morphological characters. In order to clarify the phylogenetic position of aster, the nucleotide sequence of the nuclear ribosomal DNA internal transcribed spacer (ITS) region was compared among 11 taxa in Korean native aster. The size of ITS1 and ITS2 ranged from 283 to 286 bp and from 251 to 257 bp, respectively. The size of 5.8S region was 164 bp in 11 taxa. The total length of ITS1, 5.8S and ITS2, A. tripolium was shown to be the shortest length, 701 bp; and A. scaber was shown to be the longest length, 706 bp. The G+C content of ITS1 ranged from 47.9% to 51.2% and ITS2 ranged from 52.2% to 55.1%. The range of each taxon was narrow. The total length of the character matrix was 708 characters. Among them, total indel showed 9; in the ITS1 region indel showed 6 it was 67%; and in the ITS2 region, indel showed 3. Most of the indels showed deletion or insertion of only one base pair, but in A. spathulifolius deleted two base pairs and in A. tripolium deleted five base pairs. But in A. yomena, A. hayatae, A. koraiensis, and A. hispidus, the indel was not detected. Phylogenetic trees did not even make a difference inter-genus, but A. yomena and A. koraiensis called genus Kalimeris and genus Gymnaster, respectively; these constituted a clade. A. hispidus called genus Heteropappus was placed as a sister group to the clade of A. ageratoides and A. glehni.

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James F. Hancock, Peter W. Callow, Sedat Serçe, and Phan Quynh Son

Variation in 14 horticultural traits of native octoploid Fragaria L. from North and South America was examined in a greenhouse. Significant levels of variation were found for all but a few of the traits at the species, subspecies, regional and genotypic level, with the highest amount of variation generally being partitioned among genotypes. Fragaria chiloensis (L.) Miller was superior to F. virginiana Miller for crown number, fruit weight, soluble solids and seed set, while Fragaria virginiana was superior for runner production, peduncle length, fruit number, fruit color and winter hardiness. Fragaria chiloensis ssp. pacifica Staudt had the highest soluble solids and among the earliest bloom dates, highest crown numbers and highest seed set. Fragaria chiloensis ssp. chiloensis f. chiloensis (L.) Duch. produced the largest fruit and among the earliest bloom dates and longest peduncles. Fragaria chiloensis ssp. chiloensis f. patagonica (L.) Duch. had among the highest crown numbers and the highest percentage seed set. Fragaria virginiana ssp. platypetala (Rydb.) Staudt produced the most crowns and its fruit ripened earliest. Fragaria virginiana ssp. glauca (Wats.) Staudt were the latest flowering, had the darkest fruit color and the most flowering cycles. Fragaria virginiana ssp. virginiana Duch. displayed the most winter dieback, the longest peduncles, and the highest flower and runner numbers. No significant differences were observed in any of the examined traits between F. chiloensis ssp. pacifica and F. chiloensis ssp. lucida, or F. virginiana ssp. grayana and F. virginiana ssp. virginiana. A number of individual genotypes were superior for more than one trait. CFRA 0024 possessed unusually high crown numbers, was extremely early blooming and displayed multiple fruiting cycles. CFRA 1121 had unusually long peduncles and much higher than average values for fruit weight, soluble solids, fruit color and seed set. CFRA 0094 was extremely early flowering and had much darker fruit color than most other F. chiloensis genotypes. CFRA 0368 flowered unusually early and had among the largest fruit. CFRA 0366 possessed unusually long peduncles and the largest fruit of any North American genotype. CFRA 0560 and CFRA 1369 had an unusual combination of multiple flowering cycles and high runner production. CFRA 1170 and 1171 were unusually late fruiting and had high numbers of large fruit on long peduncles. CFRA 1385 and JP 95-3-1 had extremely high flower numbers, long peduncles and large fruit.