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Zhe Cao, Zhanao Deng and Mike Mclaughlin

classification. The characteristics commonly examined in caladium include floral and inflorescence morphologies, leaf shape and coloration pattern, and tuber morphology. Cytogenetic information such as chromosome number has not been used in the classification of

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Min Deng, Jianjun Chen, Richard J. Henny and Qiansheng Li

nation in croton production ( Brown, 1995 ). However, there is no information regarding the cytology of crotons cultivated in Florida. The objectives of this study were to examine the chromosome number and karyotype of selected crotons cultivated in

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A. Estilai, A. Hashemi and K. Truman

Edible chia seeds, purchased from the local markets in Guatemala, Mexico, and southern California, were used for species identification, chromosome counts, karyotype construction, and meiotic analyses. Plants raised from those seeds had ovate leaves, dense racemose inflorescences, pale-blue flowers, and were identified from herbarium specimens as Salvia hispanica L. Mitotic analyses of root tips from 50 plants showed 2n = 12—the lowest chromosome number in the genus. Chromosomes were small, ranging from 2 to 3.5 pm. One pair of chromosomes was metacentric (with the long arm: short arm ratio, r = 1.5), four pairs were submetacentric (r = 2.6 to 3.6), and one pair was telocentric (r = 12). Meiosis was regular and six bivalents were observed at metaphase I. Ring and rod bivalents averaged 1.53 ± 1.05 and 4.47 ± 1.05, respectively;

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Joseph Tychonievich and Ryan M. Warner

chromosome number. Crosses between closely related species with the same chromosome number are more likely to hybridize and produce fertile progeny, whereas crosses between distantly related species with different chromosome numbers are more likely to either

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Supriyo Basak, Guangyan Wang, Xudong Sun and Yongping Yang

showed marked morphological differences, with YP being generally larger and also producing bigger turnips than QTP landrace ( Table 1 ; Supplemental Fig. 1 ). Germinated root tips were used for determination of somatic chromosome number. Glycine max

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Hamid Ahmadi and Royce S. Bringhurst

Two groups of Fragaria decaploid (2n = 70, x = 7) breeding populations were studied. The first was derived from pentaploid (2n = 35) and hexaploid (2n = 42) natural or synethetic interspecific hybrids between octoploid (2n = 56) F. chiloensis (L.) Duch. or F. virginiana Duch. both from California, and various Fragaria diploids (2n = 14). Their chromosome number was doubled with colchicine or through the naturally generated unreduced gametes. They were selfed repetitively, intercrossed, and open pollinated. Gametic viability of the hermaphroditic and female decaploid hybrids exceeded 50%. The hybrids exhibited heterosis for runner production and vegetative vigor. Fragaria chiloensis bred for large fruit and desirable fruit qualities, and, in combination with diploids F. vesca L. and F. viridis Duch., resulted in hybrids that produced a single early spring crop and prolific runner production throughout the summer. Fragaria virginiana L. derivatives were characterized by high pollen fertility, and by day neutrality (photo-insensitivity). Together, they may contribute genes for adaptation to various regions and climates of the world and for pest and disease resistance. The second and most important group of decaploids involved here were those derived from hybrids between day-neutral octoploid cultivars (F. ×ananassa) crossed to F. vesca or F. viridis. This group of decaploids combined the genomes of the best octoploid cultivars with those of the above diploid species: facilitating the incorporation of genes responsible for high yield, day neutrality, and excellent fruit quality into the decaploid strawberries.

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Ryan N. Contreras and Kimberly Shearer

can provide greater insight into a genus and thus aid in developing breeding strategies. The base chromosome number of Acer is x = 13. Cytological reports for maples include a range of ploidy levels ( Darlington and Wylie, 1956 ). The greatest

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Joseph J. Rothleutner, Mara W. Friddle and Ryan N. Contreras

collaborating with Hoyt Arboretum (Portland, OR) to identify and evaluate our germplasm collection, with little success in identifying unknown samples. The base chromosome number of Maloideae is 17 and is thought to be of allopolyploid origin—perhaps derived

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Darren H. Touchell, Thomas G. Ranney, Dilip R. Panthee, Ronald J. Gehl and Alexander Krings

average of 22.1 Mg·ha −1 per year. Expanding germplasm collections with accessions from other areas, particularly Asia, may capture greater genetic diversity. The base chromosome number for Arundo has been reported as x = 6 or 12 ( Hardion et al

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Keri D. Jones, Sandra M. Reed and Timothy A. Rinehart

van Gelderen, 2004 ), little scientific literature exists related to breeding and genetics of this or related species. In particular, only a few cytological studies have been conducted in Hydrangea L. Chromosome number within the genus ranges from 2