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Alice (Jack) Le Duc

Several collecting trips in Mexico, in association with a monographic revision of a portion of the genus Mirabilis, have produced several species which show promise as new perennial landscape plants. Mirabilis pringlei Weatherby, with its showy pink flowers, has potential as a striking summer blooming plant, particularly when used as a container accent plant. Equally promising are two as yet unnamed species, their fragrant white flowers opening in the evening, seem ideal as terrace or patio accents.

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F. V. Pumphrey and R. K. Schwanke

Abstract

Irrigation water was applied at various growth stages to peas (Pisum sativum L.) grown for processing. Irrigation increased all growth characters measured, extended blooming and pod setting, and delayed maturity 1 to 7 days. Irrigation at pod filling increased yield more than irrigation at any other growth stage and produced the greatest yield increase per cm of water applied. Irrigated peas were of lower quality for processing than non-irrigated peas.

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David Shupert*, Natalie Anderson, and David Byrne

Seedlings from three interspecific backcross rose populations derived from a F1 population were used to study inheritance of several traits in roses. Three F1 plants (WOB13, WOB21, and WOB26) from the hybridization of the diploid parents Rosa wichuraiana and `Old Blush' were backcrossed to `Old Blush' to produced three populations to observe the segregation of several morphological and disease resistance traits. The segregating rose traits in the backcrosses are no prickles on stems, non-recurrent blooming habit, white single flowers, black spot resistance, and powdery mildew resistance present in the Rosa wichuraiana parent compared to prickles on stems, recurrent blooming habit, pink double flowers, black spot susceptible, and powdery mildew susceptible present in the `Old Blush' parent. Visual data was collected for the segregating traits using color standards and rating scales as appropriate. The three populations expressed the segregating traits to varying degrees. Under the environmental conditions at College Station, Texas the population `Old Blush' × WOB26 had a greater expression of the traits for no prickles on stems, recurrent blooming habit, disease resistance to black spot, and disease resistance to powdery mildew, which are traits desired in breeding programs. The segregation of flower color (white/pink), and flower type (single, semi double, and double) were similar in all three populations.

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Chantalak Tiyayon and Anita Nina Azarenko

Pollen development is an important event in plant reproduction. Hazelnut (Corylus avellana) male flower differentiation starts in summer and pollen shed is in the winter. Hazelnut pollen shed can vary up to 3 months between early to late flowering genotypes. Microsporogenesis and microgametogenesis of hazelnut is not well understood. Pollen development and differentiation of nine genotypes, representing early to late blooming cultivars from the National Clonal Germplasm Repository in Corvallis, Ore., were studied. Catkins were collected weekly from Aug. to Nov. 2002. Tissue sections were examined under the light microscope. Microsporogenesis was divided into five stages: archesporial cells, sporogenous cells and parietal layers, pollen mother cells (PMC), tetrads, and microspores. Microgametogenesis was distinguished between young pollen grains (uninucleate) and mature pollen grains (binucleate). On 4 Aug., cultivars were at different developmental stages of microsporogenesis. Early blooming cultivars had PMCs present. Later-blooming cultivars only contained archesporial cells. PMCs were present in all cultivars by 22 Aug. Microspores were observed on 26 Sept. in all cultivars. This study contributes to a better understanding of male gametophyte development in hazelnut, which has increased our ability to correlate hazelnut pollen development with bloom phenology.

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Zena Rawandoozi, Timothy Hartmann, David Byrne, and Silvia Carpenedo

moderately weak correlation was observed between BD with FDP (−0.46); however, earlier blooming does not necessarily result in a longer development period. Table 2. Phenotypic correlations among 10 peach phenological and fruit quality traits in nine peach

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J. D. Norton, C. E. Boyhan, Hongwen Huang, and B. R. Abrahams

On March 13-15, 1993 Alabama and much of the eastern United States experienced an unusually severe winter storm. This afforded the evaluation of plum cultivar production under cold stress. The highest yielding variety that bloomed before the storm was Bruce 12-4 with 28 kg/tree. Bruce 12-4 is noted for blooming over an extended period of time and producing very heavy yields. The average yield of the top five performers that bloomed after the storm was 51 kg/tree. The lowest temperature recorded at the test site, Shorter, AL was -5C.

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Owen M. Rogers

Current lilac breeding programs at the University of New Hampshire focus on the later (June) blooming species of Syringa with goals of extending the season of bloom selecting slower growing forms and developing lines with double flowers. Progress toward these goals and others, e.g., true dwarfs, will be discussed and illustrated.

Every university in the northeast includes woody ornamentals in its program to some degree. The University of New Hampshire is an official test site for ornamental from NE-9 and NC-7 germplasm programs and the National Arboretum's new introduction program. The value of these programs and their future direction will be discussed.

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W.R. Okie, T.G. Beckman, G.L. Reighard, W.C. Newall Jr., C.J. Graham, D.J. Werner, A.A Powell, and G. Krewer

This paper describes the climatic and cropping conditions in the major peach [Prunus persica (L.) Batsch] producing areas in the southeastern United States in 1996. The peach and nectarine crop was the smallest since 1955 due to a series of unusually cold temperatures in February, March, and April. Crop set was not strictly a function of late blooming. No variety produced a full crop across the region. Many reputedly hardy peaches cropped poorly. The only peach or nectarine varieties that produced substantial crops in multiple locations were `La Premiere', `Ruston Red', and `Contender'. Cropping ability of some breeding selections shows that peach frost tolerance may be improved further.

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L. Rallo, G. C. Martin, and S. Lavee

Abstract

Differences in pistil abortion did not account for variation in fruiting among ‘Manzanillo’ (biennal bearing), ‘Rubra’ (regular cropping), and ‘Swan Hill’ (strong blooming but unfruitful) olives (Olea europaea L.). Competition among normal fruits in an inflorescence seems to be a main factor in regulating final crops. Parthenocarpic fruit of ’Manzanillo’ and ‘Swan Hill’ did not exhibit fruit competition. A high percentage of ovules in ‘Swan Hill’ contained poorly developed embryo sacs at anthesis and were not fertilized. Most of the few parthenocarpic fruit formed eventually shriveled and abscised.

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Allen D. Owings, Gordon E. Holcomb, Anthony L. Witcher, C. Allen Broyles, and Edward W. Bush

All-American daylily cultivars named from 1994-2004 were evaluated for landscape performance and daylily rust (Puccinia hemerocallidis) susceptibility during 2003 and 2004. Cultivars included `Black-Eyed Stella', `Bitsy', `Leebea Orange Crush', `Plum Perfect', `Judith', `Starstruck', `Frankly Scarlet', `Lullaby Baby', `Lady Lucille', and `Chorus Line'. Bareroot plants were planted in raised beds composed of an Olivier silt loam soil in full sun and received irrigation as needed to prevent stress. Visual quality ratings were made weekly from 19 Apr. to 25 Oct. 2003 and 15 Mar. to 20 Sept. 2004. Included in the visual quality ratings were growth habit and flowering with favorable growth habit being compactness, foliage color, uniformity, and overall aesthetics, and favorable flowering being longevity and visual appeal. Flower observations were made in regard to time in bud and peak blooming periods over the same time frames. Daylily rust ratings were taken in September and November 2003 and in August and November 2004. Flowering observations indicated that Black Eyed Stella and Bitsy were the only cultivars showing reliable repeat bloom potential. Among the other cultivars, Judith was the earliest to bud and bloom but also had a blooming period of only 2 to 3 weeks compared to 4 to 5 weeks of bloom for other cultivars. Rust was most prevalent on Judith, Leebea Orange Crush, Starstruck and Lady Lucille. Judith and Leebea Orange Crush have rust symptoms earlier than other cultivars. `Plum Perfect', `Frankly Scarlet', `Bitsy', `Black Eyed Stella', and `Lullaby Baby' were least susceptible to daylily rust.