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C. L. Gupton

Abstract

Application of an absorbent starch-acrylate polymer (ASAP) to bare-rooted plants of 4 Vaccinium genotypes did not affect plant height, vigor, or chlorosis, but it increased plant mortality significantly. About 25% of all plants treated with ASAP either alone or in combination with peat died during the first year after transplanting. Surviving plants grew at about the same rate as those from other treatments during the 2nd year. A V. ashei (Reade) collection from Mississippi showed least response to soil amendments. Untreated plants of this collection grew well during the 2nd growing season and compared favorably in size with ‘Tifblue’ grown in plots with peat added.

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William R. Graves and James A. Schrader

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Hala G. Zahreddine, Daniel K. Struve, and Salma N. Talhouk

The Mediterranean region is a center of great plant diversity, harboring around 25,000 plant species, more than 20% of them endemic. Since the last Lebanese flora record in 1966, the country has experienced habitat fragmentation and destruction, due to overgrazing, overexploitation of natural resources, and urban expansion. A large number of Lebanese tree species have unexplored economic potential as either ornamental or medicinal plants. This study aimed at exploring the effects of two nitrogen fertility treatments on the growth and water use of 2-year-old Cercis siliquastrum seedlings. C. siliquastrum seeds were collected from different locations and mother trees in Lebanon in mid-Aug. 2001. Two-year old plants were then transplanted into 3-gal. containers and were randomly assigned to one of two N fertility programs, 25 ppm or 100 ppm. Plants from all redbud sources were significantly taller in the low N treatment and had significantly higher RGR than plants growing at 100 ppm N. On the other hand, plants growing at 100 ppm N level had significantly higher LAR and lower NAR than plants growing at 25 ppm N. There were significant differences in LAR and plant heights among the different sources. Water use was conducted monthly. It ranged from 3.6 × 10-4 to 1.3 × 10-3 g·cm Ht-1 per hour at 25 ppm and from 2.6 × 10-4 to 1.3 × 10-3 g·cm Ht-1 per hour at 100 ppm N through the experiment.

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M. Gambardella, A. Cadavid, V. Díaz, and R. Pertuzé

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Gail E. Barth

A research program is being conducted to support the development of superior varieties of Ixodia achillaeoides for cut flower production. This species is an everlasting daisy in the Asteraceae, which is produced on a woody perennial bush and is currently both harvested from the wild and cultivated in Southeastern and Western Australia. Ixodia shows a high degree of variation in plant form, flower characteristics, and flowering dates throughout its geographic distribution. In our assessment program, seedlings are screened for a range of morphological and flowering characteristics, and clonal selections are established under cultivation to assess suitability to row culture. The goal is the development of selections with known flowering characteristics and disease tolerance for fresh and dried flower markets and for flowering pot plants. Description is given of assessment criteria for selection of varieties for dried and fresh markets. Seventy selected varieties are currently being assessed in randomized block plantings at two sites in South Australia. Preliminary results and descriptions are presented for superior selections made for dried flower markets. The postharvest performance of selections for fresh markets will be discussed. Research on control of flowering will be presented.

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J.F. Hancock, C.A. Finn, S.C. Hokanson, J.J. Luby, B.L. Goulart, K. Demchak, P.W. Callow, S. Serçe, A.M.C. Schilder, and Kim E. Hummer

An elite group of 38 strawberry accessions representing all subspecies of the beach strawberry [Fragaria chiloensis (L.) Miller] and the scarlet strawberry (F. virginiana Miller) was planted in a replicated design at five locations across the United States, and evaluated for plant vigor, flowering date, runner density, fruit set, fruit appearance, and foliar disease resistance. Considerable genotyp× location interaction was observed for many of these traits. However, a few genotypes were impressive at all locations including PI 551735 (FRA 368) with its unusually large, early fruit, and PIs 612486 (NC 95-19-1), 612493 (Frederick 9), and 612499 (RH 30), which were very vigorous and had unusually good fruit color. Genotypes that were superior at individual locations included PIs 551527 (FRA 110) and 551728 (Pigeon Pt.) in Maryland for their large fruit, and PI 612490 (Scotts Creek) in Oregon which had extremely large fruit, superior color, firmness, and flavor. The PIs 612495 (LH 50-4), 612498 (RH 23), and 612499 (RH 30) performed well as day neutrals at multiple sites.

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James F. Hancock, Peter W. Callow, Sedat Serçe, and Annemiek C. Schilder

The performance of four California and 11 eastern cultivars of Fragaria×ananassa Duchesne in Lamarck, and 12 elite F1 hybrids of Fragaria×ananassa with F. virginiana Miller in their immediate background was evaluated in a producer's field with and without methyl bromide-chloropicrin fumigation. Averaged across all genotypes, plants in nonfumigated soils had 43% fewer runners, 18% smaller fruit, and 46% lower yields than did plants on fumigated soil. They also had an average of 27% fewer crowns, 49% more root discoloration, significantly fewer fine roots, and showed symptoms of the black root rot syndrome. The most commonly isolated pathogens from discolored roots were Pythium sp., Rhizoctonia sp., Idriella lunata P.E. Nelson & K. Wilh., and the root-knot nematode (Meloidogyne hapla Chitwood). The performance of all genotypes was enhanced by fumigation, although the F. virginiana hybrids performed comparatively better than the other cultivars on nonfumigated soils.