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Maria Jose Gonzalo, Elisabet Claveria, Antonio J. Monforte, and Ramon Dolcet-Sanjuan

is the method with best results to produce DHLs in melon ( Sauton and Dumas de Vaulx, 1987 ). The pollination with irradiated pollen, at low irradiation levels, induces the growth of parthenocarpic fruit without zygotic embryos and the presence of

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Elisabet Claveria, Jordi Garcia-Mas, and Ramon Dolcet-Sanjuan

Homozygous doubled haploid lines (DHLs) from new cucumber (Cucumis sativus L.) accessions could be useful to accelerate breeding for resistant varieties. DHLs have been generated by in vitro rescue of in vivo induced parthenogenic embryos. The protocol developed involves the following: 1) induction of parthenogenic embryos by pollinating with pollen irradiated with a Co60 γ-ray source at 500 Gy; 2) in vitro rescue of putative parthenogenic embryos identified by their morphology and localized using a dissecting scope or X-ray radiography; 3) discrimination of undesirable zygotic individuals from the homozygous plants using cucumber and melon SSR markers; 4) determination of ploidy level from homozygous plants by flow cytometry; 5) in vitro chromosome doubling of haploids; and 6) acclimation and selfing of selected lines. Codominant markers and flow cytometry confirmed the gametophytic origin of plants regenerated by parthenogenesis, since all homozygous lines were haploids. No spontaneous doubled haploid plants were rescued. Chromosome doubling of haploid plants was accomplished by an in vitro treatment with 500 μm colchicine. Rescue of diploid or chimeric plants was shown by flow cytometry, prior to their acclimation and planting in the greenhouse. Selfing of colchicine-treated haploid plants allowed for the perpetuation by seed of homozygous lines. The high rate of seed set, 90% of the lines produced seed, facilitated the recovery of inbred lines. Despite some limiting factors, parthenogenesis is routinely used in a cucumber-breeding program to achieve complete homozygosity in one generation. Breeding for new commercial hybrid cultivars will be accelerated. DHLs are ideal resources for genomic analyses.

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Agustin Huerta and Ramon Dolcet-Sanjuan

Adventitious shoots and viable plants were regenerated from bell pepper (Capsicum annuum L.) cultivars and dihaploid lines (DHLs) obtained from F1 hybrids via androgenesis (Dolcet-Sanjuan et al., in press). Hypocotil and cotyledon sections from in vitro-germinated seeds were used as explants. A modified MS medium (Murashige and Skoog, 1962) supplemented with IAA (0 to 3.2 μM) and BAP (0 to 100 μM) was used in a 3-week-long shoot primordia induction phase. Shoot elongation was best performed in the same basal medium, but supplemented with silver thiosulfate and GA3. Shoots were regenerated from eight selected DHLs (`C213', `C215', `C218', `C2123', `C2125', `C3111', `C3113', and `P493') and two cultivars (`Padrón' and `Yolo Wonder'). The percentage of cotyledon sections with shoot primordia after the induction phase was not genotype-dependent and always higher than with hypocotil sections (93.4% and 17.9%, respectively). The number of shoot primordia per responsive cotyledon section was also higher than with hypocotil sections (3.3 and 1.7, respectively). The genotype had a significant effect on the number of shoots regenerated per responsive cotyledon (1.1 to 5.5) or hypocotil (0.5 to 3.5) section. All adventitiously regenerated plants were fertile. This adventitious shoot regeneration protocol is being used to obtain transgenic plants from sweet bell pepper genotypes.

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Xuefei Ning, Xianlei Wang, Zhijie Yu, Simeng Lu, and Guan Li

genome of melon (DHL92) has been sequenced, an improved anchoring of the assembled melon genome was published ( Argyris et al., 2015b ; Garciamas et al., 2012 ). The consensus ICuGI genetic map was also anchored to the reference genome of melon (DHL92

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Taifeng Zhang, Jiajun Liu, Shi Liu, Zhuo Ding, Feishi Luan, and Peng Gao

the dwarf parent (‘X090’) were first cleaned and then aligned with the melon reference genome (DHL92) using BWA (version 0.6.1-r104), from which merged alignments were sorted and read duplicates were removed using SAMTOOLS’s (version 0.1.19) rmdup

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Iban Eduardo, Pere Arús, Antonio José Monforte, Javier Obando, Juan Pablo Fernández-Trujillo, Juan Antonio Martínez, Antonio Luís Alarcón, Jose María Álvarez, and Esther van der Knaap

different mapping populations, such as F 2 , double haploid lines (DHLs) ( Monforte et al., 2004 ), and recombinant inbred lines ( Périn et al., 2002b ). With the analysis of the genomic library of NILs, a larger number of QTLs for all traits has been

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Ryan J. Hayes and Yong-Biao Liu

blade, DHL = deteriorated heart leaf, DMR = deteriorated midrib. CA chamber experiments. In the CA chamber experiments, symptoms identical to those in the MA bags were observed. The shelf life weight rating increased from 0.06 at 5.0% O 2

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Givago Coutinho, Rafael Pio, Filipe Bittencourt Machado de Souza, Daniela da Hora Farias, Adriano Teodoro Bruzi, and Paulo Henrique Sales Guimarães

Bragantia 72 133 139 Teixeira, D.H.L. Oliveira, M.S.P. Gonçalves, F.M.A. Nunes, J.A.R. 2012 Selection index for simultaneously improving fruit production components of assai palm Pesqui. Agropecu. Bras. 47 237 243 Vieira, S.D. Souza, D.C. Martins, I

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Ria T. Leonard, Amy M. Alexander, and Terril A. Nell

( Reid and Jiang, 2005 ; Staby and Reid, 2007 ; van der Hulst, 2004 ; van Gorsel, 1994 ; van Meeteren, 2007 ). Many farms and floral internet businesses currently use rapid delivery companies such as FedEx Corp. (Memphis, TN), DHL Express (Plantation