George D. Nanos

Irrigation and harvest time affect almond kernel quality and composition

Abstract The effect of irrigation and harvest time was studied with respect to almond kernel quality with two almond cultivars. Kernel quality analyses included kernel weight, moisture content, kernel oil quality and composition, and sugar content and composition. ‘Ferragnes’ kernels had similar oil content and quality but higher oleic acid content than ‘Texas’ almonds. Various differences were also found in sugar content and composition between the two cultivars. Irrigation delayed almond maturation, had no effect on oil and sugar content, but improved oil composition with higher oleic acid content and sugar composition with higher sucrose content compared to dry-grown almonds. Late harvested almonds contained more dry matter per kernel, higher oil content but of lower quality, based on the UV absorption coefficients and oil composition, and higher sugar content mainly due to further sucrose accumulation compared to early harvested almonds.

Survival and Development of Immature Stages of the Mediterranean Fruit Fly (Diptera: Tephritidae) in Citrus Fruit

Abstract We studied, under laboratory conditions, the performance of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), immature stages in intact whole fruit of three sweet orange varieties, lemon, and bitter oranges. Both citrus variety and fruit part (flavedo, albedo, and pulp) had strong effects on larval performance, smaller effects on pupae, and no effects on eggs. Fruit peel was the most critical parameter for larval development and survival, drastically affecting larval survival (inducing very high mortality rates). Among fruit regions, survival of larvae placed in flavedo was zero for all varieties tested except for bitter orange (22.5% survival), whereas survival in albedo was very low (9.8–17.4%) for all varieties except for bitter orange (76%). Survival of pupae obtained from larvae placed in the above-mentioned fruit regions was high for all varieties tested (81.1–90.7%). Fruit pulp of all citrus fruit tested was favorable for larval development. The highest survival was observed on bitter oranges, but the shortest developmental times and heaviest pupae were obtained from orange cultivars. Pulp chemical properties, such as soluble solid contents, acidity, and pH had rather small effects on larval and pupal survival and developmental time (except for juice pH on larvae developmental duration), but they had significant effects on pupal weight.

Micropropagation of the strawberry tree, Arbutus unedo L.

Actively growing shoots of potted greenhouse-grown strawberry tree (Arbutus unedo L.) were initially sterilised and established in basal woody plant medium containing 11.1 μM BA. Optimum shoot proliferation was achieved on a basal WPM containing MS vitamins, sucrose, agar and 22.2 μM BA. Microshoots rooted successfully in basal in vitro medium containing 10 μM IBA or IAA, but their survival rate during acclimatisation was low. Addition of a mixture 1 part peat:4 parts perlite in the basal in vitro rooting medium (1:1 v/v) containing 10 μM IAA resulted in high rooting percentage and plantlets with branched roots. These plantlets were successfully acclimatised. This novel rooting medium can be exploited further due to its potential in commercial applications.

Peach leaf responses to soil and cement dust pollution

Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

Nutritional Characterization of Leaves and Herbal Tea of Moringa oleifera Cultivated in Greece

ABSTRACT Moringa oleifera tree was cultivated for the first time in the mild temperate climate of Greece. Moringa oleifera leaf protein and amino acid content, total phenols and flavonols, lipids, fatty acids, ash and minerals, dietary fiber and carbohydrates, carotenoids, and vitamins C and E were determined. Leaves were high in protein content (26.3%), including all the essential amino acids. They also contained 4512.2 mg GAE.100 g–1 DM of total phenols and were rich in flavonols (myricetin, quercetin, and kaempherol at 649.8, 77.2, and 37.2 mg.100 g–1 DM, respectively). Their lipid content was 5.6% (saturated fatty acids 28.33%, mono-unsaturated fatty acids 8.54%, and polyunsaturated fatty acids 61.27%). Leaves were rich in Ca, K, Mg, and P (1712.6, 1002.9, 460.4, and 194.2mg .100 g–1 DM, respectively), while other minerals (Mn, Na, Fe, Zn, Cu, and Se) were found in lower concentrations. The dietary fiber content of dried leaves was 34.1%, while the nonstructural carbohydrate content was 22.0%. They also had high carotenoid content (lutein, zeaxanthin, and β-carotene at 10.03, 1.52, and 2.02 mg.100 g–1 DM, respectively). The vitamins C and E concentrations were 203.1 and 104 mg.100 g–1 DM, respectively. The herbal tea was high in total phenols (736.9 mg GAE.L–1) and flavonols (myricetin, quercetin, and kaempherol at 203.7, 17.4, and 10.6 mg.L–1, respectively), and had antioxidant activity (protection factor: 4.2).

Effects of Organic Farming on Winter Plant Composition, Cover and Diversity in Olive Grove Ecosystems in Central Greece

The present study aimed to assess the effects of organic farming in comparison with conventional on plant composition, plant cover (%), diversity [species richness, Shannon, Simpson, and evenness (Pielous) indexes] and investigate and describe the relations among plant species richness, plant cover, indexes, and soil parameters (pH and temperature) in olive grove ecosystems during the winter. Organic olive groves had significantly greater values of cover, species richness, and Shannon and Simpson indexes than the conventional ones. Plant species richness was positively correlated to plant cover and Shannon and Simpson indexes but negatively correlated to evenness index for both farming system. Finally, plant cover was positively correlated to the Shannon and Simpson indexes for both farming systems. According to principal component analysis (PCA), for axis 1, positive correlation was detected among the plant species richness, soil temperature, and Shannon and Simpson diversity indexes, whereas for axis 2, negative correlation was detected between plant cover and soil pH. It can be concluded that the organic management system enhances herbaceous plant cover and diversity (species richness, Shannon and Simpson indexes) in olive grove ecosystems during the winter.

Application of variable rate fertilizer in a commercial apple orchard

The spatial variability of yield in an apple orchard is high due to the inherent soil variability and the impact of the environment on the trees. One practice of precision agriculture is the variable rate application (VRA) of inputs, which gives farmers the opportunity to manage field variability. The objective of the present study was to demonstrate how the use of variable rate fertilization in an apple orchard can change the farmer’s profit. For every other row, in a commercial apple orchard in central Greece, VRA was applied while the remaining rows were used as reference and received a uniform rate similar to the rate typically used by the farmer. The VRA rates of nitrogen were based on the literature which suggests that for every t/ha of apple yield, 2.45 kg/ha of N are removed from the soil in one growing season. The comparison of the results between VRA and reference treatments showed that the amount of fertilizer used in VRA treatments was reduced by 32.4% while the farmer’s profit increased by 21%. More years of research are required to give more reliable results.

Development and Evaluation of a Fuzzy Inference System and a Neuro-Fuzzy Inference System for Grading Apple Quality

ABSTRACT In this research work, a fuzzy inference system (FIS) and an adaptive neuro-fuzzy inference system (ANFIS) were developed to classify apple total quality based on some fruit quality properties, i.e., fruit mass, flesh firmness, soluble solids content and skin color. The knowledge from experts was used to construct the FIS in order to be able to efficiently categorize the total quality. The historical data was used to construct an ANFIS model, which uses rules extracted from data to classify the apple total quality. The innovative points of this work are (i) a clear presentation of fruit quality after aggregating four quality parameters by developing a FIS, which is based on experts’ knowledge and next an ANFIS based on data, and (ii) the classification of apples based on the above quality parameters. The quality of apples was graded in five categories: excellent, good, medium, poor and very poor. The apples were also graded by agricultural experts. The FIS model was evaluated at the same orchard for data of three subsequent years (2005, 2006 and 2007) and it showed 83.54%, 92.73% and 96.36% respective average agreements with the results from the human expert, whereas the ANFIS provided a lower accuracy on prediction. The evaluation showed the superiority of the proposed expert-based approach using fuzzy sets and fuzzy logic.