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Qin Yang, Yan Fu, Yalan Liu, Tingting Zhang, Shu Peng, and Jie Deng

, 2008 ; Shi et al., 2008 ). Currently, many pomologists and horticulturists have realized the practical and theoretical importance of xenia; however, although the available studies have focused on the observation and classification of xenia, this

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Xuebin Song, Kang Gao, Guangxun Fan, Xiaogang Zhao, Zhilan Liu, and Silan Dai

classification of chrysanthemum cultivars is based mainly on the flower type. Meanwhile, the flower type of chrysanthemum is affected by the ray floret shape, ray floret orientation, and the number of ray florets ( Ackerson, 1957 ; Anderson, 2006 ), especially

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Robert R. Shortell, William A. Meyer, and Stacy A. Bonos

because once superior genotypes are identified, they can be preserved through apomixis and produce uniform, stable cultivars ( Bashaw and Funk, 1987 ; Funk, 2000 ). A classification system was previously developed to characterize the large number of

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Josh A. Honig, Vincenzo Averello, Stacy A. Bonos, and William A. Meyer

have been developed from the improvement of intraspecific hybridization techniques ( Pepin and Funk, 1971 ). A classification system, based on varying combinations of pedigree information, common turf performance characteristics, and morphological

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Xiaobai Li, Weirui Li, Chenlu Di, Ming Xie, Liang Jin, Cheng Huang, and Dianxing Wu

classification. Materials and Methods Plant samples Fifty-three accessions from C. goeringii , C. faberi , C. ensifolium , C. kanran , and C. sinense were used for testing genetic markers ( Table 1 ). Fifty-three accessions were selected from 105 accessions

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R.L. Shewfelt, J.K. Brecht, and C.N. Thai

Tomato ripeness is currently assessed by a subjective visual classification scheme based on external color while maturity of green fruit is based on a destructive evaluation of internal locule development. In an effort to develop an objective method of tomato maturity and ripeness classification, external color measurements were performed on fresh, sized (6×7) `mature-green' tomatoes (cv “Sunny') initially and through ripening using a Gardner XL-845 colorimeter. Hue angle (tan-1 b/a, designated θ) provided the best objective means of ripeness classification with proposed ranges for mature-green (θ>114), breaker (101<θ<114), turning (85<θ<101), pink (64<θ<85), light red (36<θ<64) and red (θ<36) classes using average hue at the circumference. Hue angle at the blossom end was 2-12° lower than at the circumference due to initiation of color development at the blossom end. Colorimetry was not able to distinguish differences in physiological maturity of mature-green tomatoes as determined by the length of time required to develop from mature-green to breaker which varied from 1 to 22 days in the test.

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Stacy A. Bonos, William A. Meyer, and James A. Murphy

The apomictic breeding behavior of Poa pratensis L. provides an opportunity to study many unique genotypes that can vary dramatically in characteristics such as disease resistance, stress tolerance and growth habit. The classification of Kentucky bluegrass into types is based on common growth and stress performance characteristics gathered from field turf trials. These classification types include the Compact, Bellevue, Mid-Atlantic, BVMG (`Baron, `Victa', `Merit', and `Gnome'), Common, and Aggressive types. A spaced-plant nursery trial was established in May 1996 to quantify morphological and growth characteristics of 45 cultivars and selections representing the major types of Kentucky bluegrass. Plant height, panicle height, flag leaf height and length, subtending leaf length and width, rhizome spread, and longest extending rhizome were measured 10 days after anthesis. Compact type cultivars had a lower, more prostrate growth habit than the Common, Mid-Atlantic, and Bellevue types. Mid-Atlantic type cultivars had a wider rhizome spread than Compact type cultivars. Principal component analysis of morphological measurements made on spaced-plants supports the classification types of the Common, Compact, Bellevue, Mid-Atlantic, and BVMG, but not necessarily the Aggressive type.

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Gary W. Stutte and Elizabeth C. Stryjewski

Manual methods for estimating root length are tedious and time-consuming. Image capture and analysis systems can be used to obtain precise measurements of root length and growth angle. Root activity can also be determined through analysis of the mean pixel intensity of a digitized image. Both commercial (the IBM-compatible ICAS System) and public domain (the Macintosh-based NIH Image) image capture and analysis software have been used to analyze intact root systems. Examples of ICAS classification of hydroponic and soil-grown root systems will be presented. Advantages of the NIH Image software for analysis of micro-gravity experiments aboard the Space Shuttle will be discussed.

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Young-ju Kim and David H. Byrne

Isozyme analysis has been used for cultivar identification, but little has been done with the genus Rosa. One hundred and sixty rose accessions (species, cultivars, and hybrids) were characterized for isozyme phenotypes using starch gel electrophoresis. Six enzyme systems were stained on three electrode buffer systems. ACP, MDH, and 6PGD were run on morpholine citrate (pH 6.1) and histidine (pH 5.7), PGI and PGM were run on histidine (pH 5.7) and lithium borate (pH 8.3), and SKDH was run on morpholine citrate (PH 6.1) and lithium borate (PH 8.3). The most variable isozymes were MDH and 6PGD. MDH and 6PGD revealed 10 and 9 bands, respectively. This study showed that isozyme variability exists in roses and can be useful in their classification into species groups.

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Antonio Figueira, Jules Janick, Morris Levy, and Peter Goldsbrough

Genetic similarities among eight Theobroma and two Herrania species, including 29 genotypes of T. cacao, were estimated by rDNA polymorphism. A phenogram based on these genetic similarities significantly separated two clusters: one cluster included all Herrania and Theobroma species, except T. cacao, while the second contained 28 of 29 T. cacao genotypes. There was no clear distinction between Herrania and Theobroma species. Separation of 29 T. cacao genotypes, representing all races and various origins, had no congruency with the conventional classification into three horticultural races: Criollo, Forastero, and Trinitario. Genetic similarities in T. cacao, estimated with RAPD markers, indicated continuous variation among the generally similar but heterogeneous genotypes. The wild genotypes formed an outgroup distinct from the cultivated genotypes, a distinction supported by the rDNA data. The phenograms constructed from RAPD and rDNA data were not similar within the wild and cultivated cacao subsets.