Volume 1 Number 2 2007

CONTENTS AND ABSTRACTS

Ágnes Farkas, Edit Zajácz (Hungary) Nectar Production for the Hungarian Honey Industry (pp 125-151)

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Invited Review: The review gives an overview of the nectar and honey production of the most important melliferous plants in Hungary, where apiculture is a small but significant segment of agriculture. The climatic and soil conditions are favourable for beekeeping, with a flowering period that lasts from April to September, offering abundant nectar sources for bees. The most important bee-pollinated plants yielding unifloral honeys are: black locust/robinia (Robinia pseudoacacia L.), lime (Tilia spp.), rape (Brassica napus L.), sunflower (Helianthus annuus L.), sweet chestnut (Castanea sativa Mill.), goldenrod (Solidago canadensis L.), milkweed (Asclepias syriaca L.) and wild garlic (Allium ursinum L.). Robinia and milkweed honeys belong to the speciality honeys, so-called “Hungaricums”, while robinia and sunflower honey are popular export products of Hungary. Among the rare unifloral honey sources the nectar of Brassica, Fagopyrum, Melilotus, Phacelia and Trifolium species can be mentioned. Other nectar-producing plants of the Hungarian flora contribute to multifloral honeys, which are also popular with consumers. The nectar of early blooming fruit trees is important for honeybees in the brood rearing season, but rarely can provide unifloral honey, as well. The quantity and quality of the available nectar sources can show huge differences depending on the season, environmental conditions, the blooming stage of the plant, the age of the flowers and the time of the day.

Viorica Bălan, Valerica Tudor, Elena Topor, Mihaela Corneanu (Romania) Apricot Genetics and Biotechnology in Romania (pp 152-169)

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Invited Review: The apricot genetic improvement programme performed in Romania between 1986-2006 included clearly formulated steps such as: wide species information, gene bank development based on worldwide exchange of the biological material, widened genetic variability through intra and interspecific hybrids, in vitro immature embryo research of interspecific hybrids from the Prunus genus, mutagenesis, genetic study of different valuable combinations in F₁, F₂, backcross generation, pollen grain study of various apricot phenotypes, molecular biology investigation, and tissue culture trials. Romania conserves a rich gene bank, including 655 apricot phenotypes originating from North America, Australia, Asia, and Europe. The genetic variability induced by conventional methods demonstrates that apricot-tree species still have genetic reserves for evolution. The reproductive barriers were overcome by the biotechnological methods applied after the hybridisation of ♀Prunus armeniaca × ♂Prunus persica, or ♀Prunus persica × ♂Prunus armeniaca, saving immature embryos often aborted in interspecific hybridisation due to nutritional non-compatibility. The genetic progress of the fruit quality characteristics resulted from backcross methods and physical mutagenesis by the mutagenic agent ⁶⁰Co 3000R. The electrophoretic investigation revealed peroxidase cryoresistance in the Comandor genitor. Strong shoots were obtained from MS culture medium supplied with 2.0 μM indole-3-butyric acid (IBA) + 2.0 μM benzylaminopurine (BAP) + 0.1 μM gibberellic acid (GA₃), using meristem tips as initial explants. Shoot elongation and caulogenesis were significantly improved in a medium prepared with depleted deuterium water instead of distilled water. Heterosis was independent of the culture medium composition. The 1983-2006 breeding programme validated the following varieties: ‘Rare?’, ‘Valeria’, ‘Carmela’, ‘Viorica’, ‘Nicu?or’, ‘Adina’, ‘Alexandru’, ‘Bucovina’, ‘Siret’, ‘Atractiv’, ‘Dacia’, ‘Excelsior’, ‘Favorit’, ‘Comandor’, ‘Olimp’, ‘Tudor’, ‘Traian’, ‘Cristal’, ‘Danubiu’, ‘Aura?’, ‘Fortuna’, ‘Orizont’, ‘Amiral’, ‘Augustin’.

Alessandro Infantino, Laura Tomassoli, Ezio Peri, Stefano Colazza (Italy) Viruses, Fungi and Insect Pests Affecting Caper (pp 170-179)

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Invited Mini-Review: Capparis spinosa L. is a perennial shrub growing in the semi-arid areas of the Mediterranean basin and eastward into Iran. Caper use traces back to around ancient Egypt and Greece, used mainly for medicine and cosmetics, whereas the current major utilization is the unopened flower buds, named capers, for human consumption as a flavouring. Even though native caper shrubs grow on rocky cliffs and stone walls, in the last decades, commercial caper plantings have been developed in several Mediterranean countries for export of the pickled product, mostly to the USA and the UK. The move from a semi-wild to specialized cultivations has resulted in increasing pest problems in this crop. Since the 1970s, several pests, fungi, and viruses have been described that cause severe damage to caper leaves, flower buds and roots. In this paper, the major pathogens and insect pests of caper cultivation are reviewed.

Hulya Ozgonen, Suat Kaymak, Ali Erkilic (Turkey) An Early Warning System of Apple Scab in Turkey (pp 180-186)

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Invited Mini-Review: Apple scab caused by Venturia inaequalis (Cooke) G. Wint. is the most important disease affecting apples. If uncontrolled, the disease reduces quality and quantity of fruits during the vegetative period and can continue to develop in storage as pinpoint scab or storage scab resulting from late-season infections. Apple scab is controlled mainly by spraying fungicides and sanitation depending on the orchard size. Various varieties of apple are grown in Turkey and the susceptibility level to apple scab varies among the apple cultivars. Therefore, forecasting the disease with weather monitoring equipment is very important for determining a control strategy. This review is focused on a disease warning system of apple scab and its implementation in Turkey.

A. Aytekin Polat (Turkey) Loquat Production in Turkey: Problems and Solutions (pp 187-199)

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Invited Review: The objective of this study was to determine the current status and problems of loquat (Eriobotrya japonica Lindl., Rosaceae, Maloideae) production in Turkey and to provide solutions and alternatives. Globally, loquat production was 566,031 t in 2006, 12,310 t (about 2%) of which originates from Turkey. Turkey is thus an important world producer of loquat. Traditional loquat culture in Turkey consists of isolated trees located in gardens, family orchards or small plantings destined for local consumption. Until the last decade, loquat growing was carried out only in isolated home gardens for local consumption. After its economical value had been realized, demand for its commercial production rapidly increased. The total production in 1980 (3,000 t) increased more than four-fold by 2006 and reached about 12,310 t produced from 243,429 trees. The Mediterranean region of Turkey has the most suitable ecological conditions for growing loquat. According to 2006 statistics, 97% of total loquat production of Turkey is from the coastal Mediterranean zone. The existing organised orchards are small, each ranging from 0.1 to 6.0 hectares. The spacing is 6-8 m × 6-8 m. Soil cultivation, irrigation, pruning, fertilization and control of scab (Spilocaea eriobotryae) are carried out in organized orchards but not always for scattered trees. Fruit thinning, for the improvement of fruit quality, is not practiced. In Turkey, loquat is consumed as an early season fresh fruit. Improvement in handling and transportation efforts may help solve some of the present problems in loquat production in Turkey. Research must focus on high-density plantings, protected cultivation, and dwarf rootstocks. Future studies to find solutions to these problems should increase loquat production and may therefore increase both domestic consumption and export.

Angela Anda, Tímea Kocsis (Hungary) Evaluation of the Influence of Climatic Changes on Maize Energy Consumption in Hungary (pp 200-205)

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Original Research Paper: The effect of possible climate change on the traits of maize plants was evaluated using the simulation model of Goudriaan, based on local climatic conditions and locally measured plant characteristics. The scenarios included not only doubled CO₂ concentration, but also moderate air warming (+1.3, 2 or 3°C) and varying extents of rainfall reduction (-25%, -35% and -50%). The ratio of sensible and latent heat fluxes in plant energy consumption exhibited very little change. The probable reason for this is the equalising influence of elevated CO₂ and changes in other climatic factors. Stomatal resistance increased in all the scenarios. Stomatal closure was only observed in the case of a drastic (-50%) reduction in soil water. The intensity of photosynthesis was governed by the actual soil moisture level. Severe water deficiency led to a sharp decline in photosynthetic efficiency. Based on the local scenarios determined for Hungary, at about 20% reduction in rainfall can be expected in 2050, leading to a decline in the intensity of photosynthesis, so the role of irrigation will probably be enhanced.

M.K. Darawsheh, G. Aivalakis, D.L. Bouranis (Greece) Effect of Cultivation System on Cotton Development, Seed Cotton Production and Lint Quality (pp 206-213)

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Original Research Paper: The effect of plant density and row spacing, on growth parameters of cotton (Gossypium hirsutum L.), seed-cotton production and lint quality was studied by means of a conventional row (CR), a narrow row-low population (NR-LPP) and a narrow row-high population (NR-HPP) cultivation system. Dry mass accumulation rate, relative growth rate, net assimilation rate, fruit index, fruit/leaf area ratio, dry mass partitioning, leaf area elongation and specific leaf area mass were followed. Total dry mass and LAI were higher in NR-HPP system. Considerable differences were revealed between the treatments with the same plant population per unit land area, NR-LPP and CR; with the plants in NR to produce more total dry mass and higher LAI. Stem dry mass was less affected by row spacing and more by plant density along row. Plants in NR-HPP partitioned elevated proportion of total dry mass to vegetative parts. Fruit index and fruit-leaf area ratio were lower in NR-HPP and higher in CR. Α significant negative correlation existed between SLM and LAI. Fruit load considerably affected most growth parameters and significant negative correlation existed between fruit growth rate and growth rate of vegetative parts and Leaf Elongation Rate. Fruit load affected less the growth parameters of NR-LPP. Advantage of high population density of NR to produce higher LAI and dry mass in early growth stage did not exploit under the prevailed weather conditions due to excessive canopy and vegetative growth. Seed-cotton production and lint quality were significantly lower in NR-HPP. It is concluded that the NR-HPP system may be not adaptable or a risk under inconsistent weather conditions in a marginal cotton-belt, such that of Greece.