Volumen 26 (2018): Heft 1 (June 2018)

An experiment was conducted to study the effect of different concentrations of silver thiosulphate (STS) on flower longevity of Clarkia pulchella Pursh. The buds were subjected to 0.1, 0.25, 0.5, 0.75 and 1 mM of STS for 1 h pulse treatment. A separate set of flowers kept in distilled water was designated the control group. STS treatment resulted in improved flower longevity besides maintaining higher fresh and dry mass, water content and floral diameter. Conversely, total phenols, lipid peroxidation and lipoxygenase (LOX) activity decreased. The flowers treated with STS showed a significant increase in the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). Amongst various grades used, 0.5 mM STS was found to be most effective in enhancing the flower longevity by 1.5 days. The present study reveals that STS maintains lower LOX activity, thereby increased membrane stability index by improving the activity of antioxidant enzymes.

The present research was conducted to find influence of salicylic acid (SA) at 0.5, 1, and 2 mM and potassium nitrate (KNO₃) at 250, 500, and 1 000 ppm on reproductive and vegetative parameters, and color characteristics of saffron under field condition. The results indicated the highest a, L, and chroma and the lowest b at 2 mM SA treatment. The highest flowering appearance rate and membrane stability index and the lowest electrolyte leakage were observed at 2 mM SA and to lesser extent at 1000 ppm KNO₃. The highest flower number, corolla dry weight, and stigma dry weight was shown in plants treated with SA. Chlorophyll a content and Fv/Fm value increased with the application of 2 mM SA. The data indicated the effectiveness of SA on the growth of saffron.

The aim of the study was to assess the usefulness of hybrid drying methods (convective-microwave and convective-microwave-ultrasound) for sour cherry fruit preservation compared to convective drying. As the raw material, three sour cherry cultivars varying in quality characteristics (‘Łutówka’, ‘Debreceni Bötermo’, ‘Nefris’) were used. Before drying, fruits were subjected to osmotic treatment. Three different drying methods were examined: 1) convective (C), 2) hybrid with microwaves (C-MV) and 3) hybrid with microwaves and ultrasound (C-MV-US). As the quality indicators of the investigated processes, the changes in chemical composition, including alterations in the main groups of bioactive components, as well as in the antioxidant potential were monitored at each production stage. It was found that, when compared to convective drying, the use of the hybrid techniques allowed the drying time to be reduced from 9 to just 3 hours. Furthermore, employing hybrid drying eliminated the problems associated with the dehydration barrier observed during convective drying of the cultivar ‘Debreceni Bötermo’. Regrettably, although the ultrasound used as the additional source of energy in the hybrid method slightly improved water evaporation, in general no significant effect on the retention of phenolic compounds was found. Irrespectively of the drying method, the effect of the cultivar proved to be crucial to the quality of the final product. Under the same processing conditions, ‘Nefris’ turned out to be the most promising cultivar for producing ready-to-eat fruit snacks of high nutritional value.

The aim of the study was to shorten the period of breaking dormancy in apple seeds and to improve the growth of the seedlings of ‘Gold Milenium’, ‘Ligol’ and ‘Szampion’. The whole seeds were removed from fruits directly after the harvest and were subjected to stratification (3 °C for 90 days in darkness) in distilled water or an aqueous solutions of 500 mM salicylic acid (SA), 10⁻³ M jasmonic acid (JA), gibberellin A₃ (GA₃) and 6-benzylaminopurine (BAP) at 250 mg·dm⁻³ and 100 mg·dm⁻³, respectively. Growth regulators were applied separately or in a mixture containing SA, JA, GA₃ and BAP. The germinability and seed germination rate, seedlings growth, chlorophyll content index and the maximum quantum efficiency of Photosystem II (Fv/Fm) were investigated. The obtained results revealed that stratification in water positively affected the dormancy removal in ‘Gold Milenium’, ‘Ligol’ and ‘Szampion’ seeds. Application of SA, GA₃, BAP, JA during seed stratification additionally stimulated the seeds’ germination rate as well as the growth of seedlings, index of chlorophyll content and maximum PSII efficiency (Fv/Fm). The most pronounced results were obtained after the seed stratification in GA₃ alone or in a mixture containing SA, GA₃, BAP and JA. Due to such a treatment, the germination of ‘Ligol’ seeds increased by 40% and they germinated faster in comparison to the control seeds. Such treatments also promoted the growth of seedlings, chlorophyll content and maximum quantum efficiency of Photosystem II (Fv/Fm). The present study indicates that the application of GA₃ or the mixture of SA, GA₃, BAP and JA during the stratification of seeds is an effective method to increase and accelerate the germination of seeds and juvenile seedlings’ growth in order to shorten the apple breeding cycle. Further studies are needed to optimize the appropriate concentration of growth regulators applied simultaneously during seeds stratification.

Barberry (Berberis vulgaris L.) fruit is an important source of anthocyanins and is used for consumption and in medicine. However, fruit production of barberry is not regular. Two experiments in four locations were conducted on this plant to explore if it is alternate bearer and also to investigate carbohydrates and phenolics contents in leaves and shoots during growth season. Evaluation of barberry shrubs in three different location showed strong alternate bearing. The value of leaf number to berry number ratio was small. A correlation was found between tree age and alternate bearing index (ABI), because elder shrubs exhibited more ABI. Total carbohydrates and phenolics contents in vegetative organs showed an increase during the fruit setting stage, except for the carbohydrates in shoots. The highest value of carbohydrates was observed 10 days after leaf appearance and then decrease. ON bearing shrubs showed the highest value of total carbohydrates content in leaves during fruit setting stage, after which it decreased. However, OFF bearing shrubs indicated a reducing trend in this variable. In both bearing statuses (ON and OFF trees), total carbohydrates decreased with season progression. It is concluded that this plant is strongly alternate bearer and this characteristic may be related to carbohydrates and phenolics changes in leaf and shoot organs.

Quality assessment is an important concern in the post-harvest marketing of fruits. Manual quality assessment of pomegranate fruits poses various problems because of human operators. In the present paper, an efficient machine vision system is designed and implemented in order to assess the quality of pomegranate fruits. The main objectives of the present study are (1) to adopt a best pre-processing module, (2) to select best class of features and (3) to develop an efficient machine learning technique for quality assessment of pomegranates. The sample images of pomegranate fruits are captured using a custom-made image acquisition system. Two sets of features, namely, spatial domain feature set and wavelet feature set are extracted for all of the sample images. Experiments are conducted by training both artificial neural networks (ANNs) and support vector machines (SVMs) using both sets of features. The results of the experiments illustrated that ANNs outperform SVMs with a difference in the accuracy of 12.65%. Further, the selection of wavelet featureset for training yielded more accurate results against spatial domain feature set.

This research aimed to study the effect of the position of fruits in a tree (inner or outer) and the number of fruits per panicle (one, two or three) on the growth and quality of citrus ‘Pontianak’. The study was conducted in a citrus orchard in Central Java, Indonesia for two seasons, 2014/2015 and 2015/2016. The results indicated that position of fruits on the tree did not influence weight and diameter of fruits, weight of fruit pulp, and contents of sugars and total acids. Increasing the number of fruits per panicle decreased the weight and diameter of fruits and the weight of pulp but increased the contents of vitamin C and total acids.

Field experiments were carried out at the Teaching and Research Farm, Landmark University, Omu-Aran, Kwara State, Nigeria, in the cropping seasons of 2015 and 2016. The soil at the site of the experiment is an Alfisol classified as an Oxichaplustalf or a Luvisol. The trial consisted of sole and combined applications of urea fertilizer (U) applied at 0, 60, and 120 kg·ha⁻¹ and maize cob ash (M) applied at 0, 3, and 6 t·ha⁻¹. The results showed that U and M alone or in combinations increased the soil chemical properties, growth, yield, and mineral composition of okra compared with the control. M alone at 3 t·ha⁻¹ produced optimum soil chemical properties, yield, and mineral composition of okra fruit. U alone at 60 kg·ha⁻¹ produced optimum yield of okra, while growth and mineral composition were increased when urea fertilizer was applied at 120 kg·ha⁻¹. The treatment with U applied at 60 kg·ha⁻¹ in combination with M applied at 3 t·ha⁻¹ (U₆₀M₃) produced the highest values of okra yield, while U applied at 120 kg·ha⁻¹ in combination with M applied at 3 t·ha⁻¹ (U₁₂₀M₃) has the highest growth and highest N, K, Ca, Cu, and Fe contents of okra fruit. Compared with the control and using the mean of the two years, U₆₀M₃ increased okra fruit yield by 93.3%. Therefore, for viable production of okra in low nutrient soil of the Nigeria derived savanna or similar soils elsewhere, 60 kg·ha⁻¹ U + 3 t·ha⁻¹ M (U₆₀M₃) is recommended. However, for improved mineral quality of okra, 120 kg·ha⁻¹ U + 3 t·ha⁻¹ M (U₁₂₀M₃) is recommended.

This study was aimed to investigate the effect of thiamine (Th) foliar application on some morpho-physiological aspects in coriander and fenugreek. Three levels of Th (250, 500 and 750 ppm) plus control treatment (distilled water) were studied under controlled greenhouse conditions. All the levels of Th, in particular the concentration of 500 ppm, increased the vegetative growth of coriander. 1000-grain weight, contents of nitrogen and phosphorus, carotenoid and chlorophyll b contents were the highest at a concentration of 750 ppm. Fenugreek vegetative growth also responded positively to the application of Th especially at a concentration of 750 but also 500 ppm increased the content of leaf nitrogen, chlorophyll b, carotenoids, phenolics and antioxidant activity. Overall, the performance of coriander and fenugreek was improved by the application of Th foliar at all levels.

Enhancing water productivity for sustainable crop production and water savings represents a major challenge for agricultural water management. Pot experiments under open field conditions were conducted for two years, 2016 and 2017, to assess the effects of regulated deficit irrigation under mulch on onion crop production, following a 2 × 3 factorial experiment with two soil cover systems (wheat straw mulch and no-mulch) and three irrigation levels (100%, 80%, and 60% of crop evapotranspiration), with six replications.The results indicated that onion plants were responsive to straw mulching. Bulb diameter, total yield, dry matter, and water productivity were significantly enhanced under mulch whatever the irrigation level used. The seasonal crop water requirements also considerably decreased (about 33%). The results also showed the sensitivity of onion to water stress. Yield, dry matter, and water productivity were higher under full irrigation compared to the deficit irrigation. However, when mulch was used, regulated deficit irrigation highly significantly improved water productivity and onion crop quality and quantity; and this approach could be a promising management practice to meet water shortage consequences in the dry Mediterranean region.