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Pedro García-Caparrós, Olga González-Salmerón, Mónica Pérez-Saiz, Raquel Calatrava, María Teresa Lao, Rosa María Chica, and Gumersindo De la Cruz

) Intl. J. Agr. Sci. 85 931 935 Hatamian, M. Salehi, H. 2017 Physiological characteristics of two rose cultivars ( Rosa hybrida L.) under different levels of shading in greenhouse conditions J. Ornamental Plants 7 147 155 Healy, W.E. Heins, R.D. Wilkins

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Eduardo A.S. Rosa and Ana S. Rodrigues

Broccoli (Brassica oleracea L. Italica Group) is an economically important vegetable crop and its consumption may benefit human health. Glucosinolates, a group of secondary plant metabolites found generally in the cultivated Brassicaceae, may protect against the development of certain malignancies. The objective of this study was to evaluate total and individual glucosinolate content of broccoli cultivars widely grown in southern Europe following spring vs. summer planting (early vs. late crop, respectively). Glucosinolates in primary and secondary inflorescences taken from mature plants were analyzed separately by high performance liquid chromatography (HPLC). The cultivars contained primarily 4-methylsulfinylbutyl-, indol-3-ylmethyl- and 1-methoxyindol-3-ylmethyl-glucosinolates. Total and individual glucosinolate levels varied significantly between seasons, among cultivars and between inflorescences. `Shogun' contained the highest total glucosinolate levels (between 35.2 mmol·kg-1 dry weight in primary inflorescences of the early crop and 47.9 in secondary inflorescences of the late crop). Total and individual glucosinolate levels were generally higher in the late than in the early crop. Primary inflorescences generally contained the highest glucosinolate levels in the early crop but secondary inflorescences had the highest levels in the late one.

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María Luisa Osorio-Rosales and Martín Mata-Rosas

Experiments were conducted to establish an efficient protocol of micropropagation of Beaucarnea gracilis and B. recurvata two endemic and endangered Mexican species. Multiple shoots were induced by direct organogenesis from in vitro seedlings and longitudinal sections of seedlings in both species. The highest formation of shoots per explant, both B. gracilis and B. recurvata, was obtained from longitudinal sections of seedlings on Murashige and Skoog (MS) medium supplemented with 22.2 μm 6-benzylaminopurine, induced 8.2 and 11.1 shoots per explant respectively. In vitro rooting was readily achieved on MS medium with 1 g/l activated charcoal without growth regulators. According to initial treatment and depending on where the shoots come from, the rooting rates were 61% to 100% for B. gracilis, and 83% to 100% for B. recurvata. Survival rates in greenhouse conditions for both species were 80% to 100% after 3 months. These results indicate that the micropropagation of these species of Beaucarnea is technically feasible, and that in vitro culture is a useful option for the conservation and propagation of these important endangered species.

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James S. Beaver and Juan Carlos Rosas

Heritability of length of the reproductive period and rate of seed mass accumulation in beans (Phaseolus vulgaris L.) was estimated using 170 randomly derived F6 and F7 lines from three populations evaluated in the field in Puerto Rico and Honduras during two growing seasons. Narrow-sense heritability for length of reproductive period ranged from moderate (0.43) to high (0.83), and transgressive segregation for shorter and longer reproductive period was observed for the three populations. Heritability of rate of seed mass accumulation was low (0.24) to intermediate (0.49). Lines with high yield potential, which matured 4 to 7 days earlier than the later parents L227-1 and `Catrachita', were selected. Most of the superior lines combined earlier maturity with high yield potential by having greater rates of seed mass accumulation than the early parents `Cuarentena' and `Cuarenteño'. Low to intermediate heritabilities for rate of seed mass accumulation suggest that selection for this trait would be more effective by evaluating advanced generation lines in replicated trials. Several lines yielded significantly more than L227-1 or `Catrachita' by combining long reproductive period with fast rate of seed mass accumulation.

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Gary E. Vallad, Kenneth L. Pernezny, Botond Balogh, Aimin Wen, Jose Francisco L. Figueiredo, Jeffrey B. Jones, Timur Momol, Rosa M. Muchovej, Nikol Havranek, Nadia Abdallah, Steve Olson, and Pamela D. Roberts

established on 1 May and 21 Aug. 2007 for a respective late spring and fall bacterial spot trial at the University of Florida's PSREU in Citra, FL. For both trials, tomato seedlings of the cv. Bella Rosa were transplanted at 46-cm spacing to raised, fumigated

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Edna Pesis, Rosa Marinansky, Giora Zauberman, and Yoram Fuchs

Prestorage treatment of avocado fruit (Persea americana Mill. cv. Fuerte) with a low-O2 atmosphere (3% O2 + 97% N2) for 24 hours at 17C, significantly reduced chilling injury (CI) symptoms after storage at 2C for 3 weeks. Fruit softening was also delayed by this treatment. The treated fruit had lower respiration and ethylene production rates during storage at 2C and subsequently at 17C. Electrolyte leakage was significantly lower in peel disks from treated fruit. Reducing power, expressed as total sulfhydryl groups, was higher in the peel and pulp of low-O2-treated fruit. The amount of peel chlorophyll was inversely correlated with the severity of CI symptoms.

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Rosa María Giménez Ferrer, Joseph C. Scheerens, and W. Alan Erb

Leaf disk bioassays based on oviposition and damage accrued during 72 hours were used to screen 76 strawberry (Fragaria spp.) cultivars for resistance to the twospotted spider mite (Tetranychus urticae Koch). Oviposition rates (eggs/female per day) and damage scores were both highly variable, allowing cultivars to be classified, according to a combination of these two variables, into six categories of susceptibility or resistance: highly susceptible- `Canoga', `Ozark Beauty', `Scott', and `Tangi'; resistant—'Aiko', `Annapolis', `Apollo', `Bounty', `Cardinal', `Douglas', `Dover', `Fairfax', `Fern', `Floridabelle', `Glooscap', `Governor Simcoe', `Hecker', `Kent', `Pajaro', `Parker', `Rainier', `Redcoat', and `Vesper'; and highly resistant—`Profumata di Tortona' (F. moschata Duch.). Bioassay based on oviposition rates and damage scores was considered to be an efficient method to eliminate susceptible accessions from a breeding program, but authentication of putative resistance may require further testing in vivo.

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Raul De la Rosa, Luis Rallo, and Hava F. Rapoport

In the olive (Olea europaea L.), inflorescence and flower differentiation occur in the early spring following a period of winter chilling and dormancy of the potentially reproductive buds. We examined the size, structure, and starch content of these buds during winter rest in the field and during forcing under standard growth-chamber conditions. Basic bud structure and dimensions remained unchanged during the rest period, but starch content increased in the bud's central axis. When cuttings were forced in the growth chamber, the buds followed a morphogenetic pattern similar to that observed in the field, but the sequence of developmental events could be timed more precisely. The first changes observed were the onset of axis growth and the differentiation of axillary primordia within 3 days of transfer to the growth chamber. This was followed by the initiation of new nodes, and, at 15 to 18 days, by the first signs of floral differentiation in the terminal and axillary bud apical meristems. Bud growth and differentiation were accompanied by a decrease in starch content.

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F.A. Bliss, J.C. Rosas, and P.A.A. Pereira.

The discovery of bruchid resistance in wild beans and the demonstration that theArcelin protein is responsible for the resistance, provide an opportunity to develop resistant cultivars of common bean, Phaseolus vulgaris L. Arcelin expression is controlled by multiple alleles, which impart different levels of insect resistance. In field tests in Honduras and Brazil, backcross-derived lines with the Arl-1 allele were most resistant, especially to Mexican bean weevil. Seed mixtures of 0.80 Arl-1:0.20 susceptible and equal amounts of Arl-1,Arl-2, and Arl-3, and Arl-4 containing seeds showed resistanc elevels and seed yields similar to lines homogeneous for Arl-1. Breeding lines uniform for appearance and agronomic performance, but heterogenous for resistance genes are being tested as potential new dry bean cultivars having stable insect resistance.

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Rosa Marina Arvayo-Ortiz, Sergio Garza-Ortega, and Elhadi M. Yahia

Winter squash is grown in the Northwest of Mexico for export to distant markets with risk of produce loss. A study was conducted to investigate its postharvest behavior as affected by hot water (50°C) for 0, 3. 6, 9 and 12 min, and stored at 10 or 20°C with 75% RH for 4, 8, and 12 weeks. The highest weight loss (11.35%) was in fruits without hot water treatment stored at 20°C for 12 weeks; at this temperature the weight loss was 3.65, 7.18, and 10.19% in the 4, 8 and 12 week storage period, respectively. At 10°C the weight loss was 3.41, 6.83 and 7.56% for the same period. Chlorophyll content decreased as temperature and storage period increased. β-carotene content showed no change at 10°C, but slightly increased after 8 and 12 weeks at 20°C. Fruits showed decay by Rhizopus and Aspergillus. Weight loss, chlorophyll content, and decay were not affected by length of hot water treatment. General appearance was better in fruits stored at 10°C than at 20°C.