A chill unit model was developed for ‘Starkrimson Delicious’ (Malus domestica Borkh.) apples grown under the wide range of temperature and elevations in North Carolina. The model relates air temperature to effective chill units and predicts rest completion for North Carolina-grown apples more accurately than previously reported models. The model proposes a broader range of effective temperatures and incorporates a greater negative effect when temperatures exceed 21°C for rest. According to the model, 1200 chill units are required to break rest of apple buds. Growing degree hours correlated with each apple bud developmental stage, as well as from projected date of rest completion to full bloom, were determined using various base temperatures.

This study was carried out to investigate the effect of mannitol, sorbitol and sucrose as osmotic agents on in vitro conservation of embryogenic cultures of date palm (Phoenix dactylifera, L.) Bartamoda and Sakkoty cultivars. Embryogenic cultures was obtained using MS medium supplemented with 10 mg/l 2,4-dichlorophenoxy acetic acid (2,4-D) and 3 mg/l isopentenyl adenine (2iP). Among the three types of osmotic substances used for slow growth conservation, sucrose at all concentrations gave the highest percentage of survival with Sakkoty cultivar. However, addition of 40 g/l or 60 g/l mannitol and 20 g/l sorbitol showed the highest percentage of survival percentage with Bartamoda cultivar. The different sucrose concentrations caused higher numbers of germinated embryos of the two cultivars compared with mannitol or sorbitol. Also, the number of germinated embryos was increased with increasing the storage periods till the ninth month. Genetic stability was determined using random amplified polymorphic DNA (RAPD) analysis. There were no clear genetic differences between the two osmotic agents used for preservation. The preserved cultures of Sakkoty cultivar gave the high percent of similarity while Bartamoda cultivar gave low percent of similarity. From the obtained results we can recommend using 40 g/l mannitol or 20 g/l sorbitol for in vitro preservation of Bartamoda cultivar of date palm and 20 g/l of sucrose for Sakkoty cultivar.

The present investigation was conducted during 2012, 2013 and 2014 seasons on 10-year-old Superior grapevines cultivar grown in a sandy soil, planted at 2 m within rows and 3 m between rows and irrigated using drip irrigation system at a private vineyard located at El-Khatatba, Menoufiya governorate, Egypt. The obtained data was discussed in details for the last 2 seasons only. The main objective of this investigation was to study the effect of fulvic acid foliar application 9 ml/liter /vine, either alone or in combination with micro-elements (Fe SO4. 7H2O at 0.36 g + Zn SO4.7H2O at 0.18 g + MnSO4. H2O at 0.18 g) and bio-fertilizers (Trichoderma viride + Trichoderma harzianum + Serratia sp. + Pseudomonas fluorescens + Bacillus polymyxa) at 7.14 ml/liter/vine (10 4 /ml per fungi and 10 9 /ml per bacteria viable cell) on vegetative growth, total chlorophyll content, yield, physical and chemical characteristics of cluster and quality of berries, total carbohydrates, total N and C/N ratio in canes of Superior seedless grapevines. Results revealed that the combined treatment of fulvic acid, micro-elements plus bio-fertilizers induced indispensable positive effects for enhancing vegetative growth, total chlorophyll content, yield, physical and chemical characteristics of cluster and quality of berries, total carbohydrates, total N and C/N ratio in canes of Superior grapevines. A stronger effect may probably support the hypothesis of that humic substances have different effects on plant adequately supplied with nutrients, in sustainable or organic viticulture for production of organic products, which can be a noteworthy alternative to synthesized chemicals fertilizers to produce a healthy product-free from their toxic residues and fit for export. Foliar spray applications of these products can have prospects for optimal economical use in terms minimizing the cost of production and in turn increased the income of vineyards.

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