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Abstract

Tea (Camellia sinensis) is an important beverage crop cultivated in the tropics and subtropics under acid soil conditions. Increased awareness of the health-promoting properties of the tea beverage has led to an increase in its level of consumption over the last decades. Tea production contributes significantly to the economy of several tea-cultivating countries in Asia and Africa. Environmental constrains, particularly water deficiency due to inadequate and/or poorly distributed rainfall, seriously limit tea production in the majority of tea-producing countries. It is also predicted that global climate change will have a considerable adverse impact on tea production in the near future. Application of fertilizers for higher production and increased quality and quantity of tea is a common agricultural practice, but due to its environmental consequences, such as groundwater pollution, the rate of fertilizer application needs to be reconsidered. Cultivation of tea under humid conditions renders it highly susceptible to pathogens and pest attacks. Application of pesticides and fungicides adversely affects the quality of tea and increases health risks of the tea beverage. Organic cultivation as an agricultural practice without using synthetic fertilizers and other chemical additives such as pesticides and fungicides is a sustainable and eco-friendly approach to producing healthy tea. A growing number of tea-producing countries are joining organic tea cultivation programmes in order to improve the quality and to maintain the health benefits of the tea produced.

Abstract

This study was conducted to assess the influence of different salinity and irrigation water treatments on the growth and development of sweet basil (Ocimum basilicum L.). Five salinity levels (0.4, 1.00, 2.50, 4.00 and 8.00 dSm-1) and three different irrigation water regimes (80, 100, 120% of full irrigation) were applied in a factorial design with three replications. Dry root weight, aerial part dry weight and aerial part/root ratio were determined and evaluated as experimental parameters at the end of growing period. Results revealed significant decreases in yields with increasing salinity levels. However, basil managed to survive high salt stress. With increasing salinity levels, decreases in growth were higher in roots than in leaves. Changes in the amount of irrigation water also significantly affected the evaluated parameters.

Abstract

Potato (Solanum tuberosum L.) is a cool season crop which is susceptible to both drought and heat stresses. Lack of suitable varieties of the crop adapted to drought-prone areas of the lowland tropics deprives farmers living in such areas the opportunity to produce and use the crop as a source of food and income. As a step towards developing such varieties, the present research was conducted to evaluate different potato genotypes for osmotic stress tolerance under in vitro conditions and identify drought tolerant genotypes for future field evaluation. The experiment was carried out at the Leibniz University of Hannover, Germany, by inducing osmotic stress using sorbitol at two concentrations (0.1 and 0.2 M) in the culture medium. A total of 43 genotypes collected from different sources (27 advanced clones from CIP, nine improved varieties, and seven farmers’ cultivars) were used in a completely randomized design with four replications in two rounds. Data were collected on root and shoot growth. The results revealed that the main effects of genotype, sorbitol treatment, and their interactions significantly (P < 0.01) influenced root and shoot growthrelated traits. Under osmotic stress, all the measured root and shoot growth traits were significantly correlated. The dendrogram obtained from the unweighted pair group method with arithmetic mean allowed grouping of the genotypes into tolerant, moderately tolerant, and susceptible ones to a sorbitol concentration of 0.2 M in the culture medium. Five advanced clones (CIP304350.100, CIP304405.47, CIP392745.7, CIP388676.1, and CIP388615.22) produced shoots and rooted earlier than all other genotypes, with higher root numbers, root length, shoot and root mass under osmotic stress conditions induced by sorbitol. Some of these genotypes had been previously identified as drought-tolerant under field conditions, suggesting the capacity of the in vitro evaluation method to predict drought stress tolerant genotypes. Most of the genotypes collected from Ethiopia were found to be susceptible to osmotic stress, except one farmers’ cultivar (Dadafa) and two improved varieties (Zemen and Belete). Field evaluation of the tested materials under drought conditions would confirm the capacity of osmotic stress tolerant genotypes to perform well under drought-prone conditions and the potential interest of in vitro evaluation as a pre-screening component in potato breeding programs.

than the controls. Thus, the application of CCC to the roots causes alterations in the water relations of developing wheat leaves, which resemble those induced by water deficiency. Introduction Preliminary investigations have shown that after the application of (2-chloroethyl)trimethylammo- niumchloride (CCC) to the roots cellular content of soluble proteins and soluble reducing sugars is in­ tensified and in vitro activity of isolated ribulose-1,5- bisphosphate carboxylase is increased in the leaves of young wheat plants (Triticum aestivum L.). Root growth

-year (2014–2019) observations is 16.45°C in June, 18.82°C in July, and 16.5°C in August. Recorded temperature anomalies resulted in drought and intensive vegetation and pasture depletion. The pond at the border of the pasture became shallow. As a result of this, the grazing animals suffered from a significant feed and water deficiency, which caused dehydration in cows and heat stress. This heat stress resulted in MCF. The clinical picture and pathological changes in the described cases were similar to MCF descriptions in veterinary literature ( 3 , 7 , 8 , 11 , 21

up less available forms of water from the soil. Sunflower is the most susceptible to soil water deficiency at flowering, fertilization and grain fill, whereas at the start and end of the growing period the sensitivity is not so evident (Jana et al., 1982; Unger, 1986; Stone et al., 1996; Erdem and Delibas, 2002). The driest months in Vojvodina are July and August, when only 15-20% of the sunflower’s potential evapotranspira- tion (ETP) minimum of 100 mm are provided (Milić, 2008). Using Hergreaves’s model, Bošnjak (1993, 1993a) and Dragović (1995) determined that

in Helia

Abstract

Increasing world temperatures are bringing about climate changes creating abiotic stress in plants. Date palm offshoot leaves (Khadrawi cv.) were analyzed for chlorophyll Chl a, Chl b, Total Chl, Chl a/b ratio, anthocyanin and carotenoid subject to salinity, drought and temperature stress under field conditions. Results demonstrated that drought and salinity stress accompanied by high temperatures in July and August significantly reduced the Chl a, Chl b, and Total Chl relative to the control. Anthocyanins, carotenoids, hydrogen peroxide, and malondialdehyde were markedly higher in July and August (45 ºC), whereas September showed lower values in these substances. Temperature reduction to 35 °C accompanied by drought or salinity stress, brought about a critical increment in relative water content and a decrease in electrolyte leakage. Although the impact of drought and salinity stress continued, the reduced temperatures in September resulted in a reduction of abscisic acid and proline concentration. Cluster analysis showed the two groups. In this first group, the significant similarity between the treatments is illustrated by the influence of the high temperature of 43–45 ºC. Recovery of photosynthesis following low-temperature, for the most part, determines plant flexibility to water deficiencies and salinity. Thermal stress, associated with salinity or drought stress is more damaging to the photosynthetic pigments than any single factor.

Abstract

Water deficiency is commonly the most important yield -restraining factor in semi-arid and Mediterranean environments. Chickpea (Cicer arietinum L.), which is one the main legume crops of the region, often experiences terminal drought. To investigate the response of chickpea genotypes to different irrigation levels, experiments were conducted in Maragheh, Northwest Iran. Three levels of irrigation including zero (rain-fed condition), full irrigation (enough water to fill the root zone profile) and two supplement irrigations (SIs) during flowering and grain filling stages were evaluated over 2013 growing season. Results revealed that plant height, canopy spread, primary and secondary branches, chlorophyll content, day to maturity, grain yield and yield components were significantly affected by irrigation regimes. However, there was no statistically significant difference between full irrigation and SI for number of pods per plant, number of seeds per pod, 100-grain weight, grain yield per unit area and grain filling rate. The seed yield of the genotypes when grown under the full irrigation condition increased at a rate of 58% over those in rain-fed condition. Investigation of grain yield and drought resistance indices revealed that FLIP 98-106C and Arman can be selected as the best tolerant genotypes to rain-fed condition. In general, under semi-arid conditions and where some limited water resources are available, SI could be an efficient management practice for alleviating the unfavourable effects of soil moisture stress on the yield of rain-fed chickpea during crucial reproductive growth stages.

Abstract

Efficient water supply is very crucial to sustenance of socio-economic growth, poverty attenuation, and food security. In most rural areas of developing countries including Nigeria water supplies are not commensurate with demand leading to a shortfall in water use and many people suffer from this scenario. This research investigated the factors responsible for rural residential water supply shortage in Southeastern Nigeria. Data were collected through the use of four mixed but complimentary methods namely questionnaire survey, interviews, focus group discussions and secondary data sources. The data generated were analyzed through the use of descriptive and inferential statistical tools. Principal Component Analysis was employed to combine the variables accounting for water supply shortage into a few underlying dimensions. The results indicated that physical environment and inadequate water supply infrastructure; socio-economic and geographical location; management and socio-cultural problems are responsible for water supply shortage in the area. Residential water supply can be sustainable in the area by regulating the influence of these factors impacting on water supply as well as lessen the implications of water deficiency. The research concludes that the process of water supply development should be stepwise in accordance with the participatory and managerial capacity of communities.

Abstract

In undulating or sloping land, water distribution in soil has a major influence on crop yield through stresses on vegetation. It is difficult to predict the impacts, however, so a crop model is required to simulate topography-related horizontal redistribution of summer precipitation and its effect on yield. This study uses a potato model (POMOD), operating with the concept of meteorologically possible yield (MPY). It was supplemented to assess precipitation redistribution by runoff on a sloping surface. Slope incline, soil moisture and rainfall intensity were environmental parameters, with rainfall intensities replaced empirically with more convenient daily rainfall sums. Differences in the water balance, as compared to a non-sloping level surface, were computed for three different parts of a notional slope 3°. Modelled differences from long-term meteorological data allowed computation of comparative long-term series of MPY in two climatologically different localities in Estonia. These were the generally moister Tallinn and the frequently dry Kuressaare regions. The locations responded differently, but there was a significant influence in both of slope on potato yield. In the frequently dry Kuressaare, yield was limited by water deficiency, as was characterized by the change in MPY through slope. However, the moister Tallinn had the worst growing conditions at the foothill due to excess water. Tallinn had the greatest topography-related differences, leading to the conclusion that excess water causes more loss in potato yield than drought in Estonia. Events of extreme rainfall drive these losses.