Agricultural Sciences

Glucosinolates in different ecotypes of Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort. widely distributed in Southern Italy and locally known as ''friariello" and ''cima di rapa", were characterized and their glucosinolate composition was compared with that of broccoli (Brassica oleracea L. var. italica). Although these two vegetables have a similar morphologic aspect, they showed a very different glucosinolate profile. While glucoraphanin, glucobrassicin and 1-methoxyindol-3-ylmethyl were confirmed as the main compounds in broccoli, gluconapin and glucobrassicanapin were identified for the first time as the molecular markers of friarielli and other Brassica rapa plants. Broccoli can by grouped according to their glucosinolates concentration by PCA analysis.

ADDITIONAL INDEX WORDS. crop water requirements, evapotranspiration, irrigation methods SUMMARY. Irrigation is a vital component of the world agriculture. It is practiced worldwide on %270 million hectares and it consents to produce 40% of our total food. Agricultural water consumption accounts for 70% of total freshwater use. The competition for this precious resource is increasing tremendously. Therefore, it is becoming critically important to optimize agricultural water use efficiency (WUE) defined as the ratio of crop yield over the applied water. This requires a shift from maximizing productivity per unit of land area to maximizing productivity per unit of water consumed. To maximize WUE it is necessary to conserve water and to promote maximal crop growth. The former requires minimizing losses through runoff, seepage, evaporation, and transpiration by weeds. The latter objective may be accomplished by planting high-yielding crops/cultivars well adapted to local soil and climatic conditions. Optimizing growing conditions by proper timing of planting and harvesting, tillage, fertilization, and pest control also contribute to improve crop growth. Most of these techniques refer to proven technology, whose implementation and/or fine-tuning in current farming systems may tremendously improve water management efficiency. In this paper, after discussing the importance of irrigation in agriculture, we will introduce basic concepts that define crop WUE and will finally review the means to improve irrigation efficiency in field vegetable crop production.

Increasing salinity tolerance and water-use efficiency in crop plants are two major challenges that agriculture must face in the next decades. Many physiological mechanisms and molecular components mediating crop response to environmental stresses have been identified. However, the functional inter-links between stress adaptation responses have not been completely understood. Using two basil cultivars (Napoletano and Genovese) with contrasting ability to respond to salt stress, here we demonstrate that reduced stomatal density, high ascorbate level and polyphenol oxidase (PPO) activity coordinately contribute to improve basil adaptation and water use efficiency (WUE) in saline environment. The constitutively reduced stomatal density was associated with a "delayed" accumulation of stress molecules (and growth inhibiting signals) such as abscisic acid (ABA) and proline, in the more tolerant Genovese. Leaf volatile profiling also revealed cultivar-specific patterns, which may suggest a role for the volatile phenylpropanoid eugenol and monoterpenes in conferring stress tolerance via antioxidant and signalling functions.

A field experiment was conducted in Southern Italy to investigate the effect of different nitrogen (N) rates (0, 100 or 300 kg ha À1) on the number of branchings and leaves per plant, plant height, yield of above-ground fresh biomass, total leaf area, dry weight, leaf-to-stem ratio, leaf essential oil content and the essential oil quality at commercial harvest (full bloom) of the three cultivars of basil (Ocimum basilicum L.): (i) ''Mostruoso mammouth'' (MM); (ii) ''Genovese profumatissimo'' (GP); (iii) ''Napoletano a foglia di lattuga'' (NFL). Nitrogen fertilization up to 300 kg ha À1 increased yield of above-ground and leaf fresh biomass, leaf essential oil yield, but it did not affect leaf-to-stem ratio, plant height and the number of branchings per plant. The increase in essential oil yield induced by N fertilization depended on an increase in both leaf essential oil concentration and leaf biomass. The increase in LAI with increasing N fertilization was due to an increase in leaf number per plant rather than in individual leaf expansion. The cultivar GP was different in morphology from MM and NFL, since it had greater leaf number and plant height, but lower leaf-tostem ratio and LAI. The physiological efficiency of N use (PE) in producing above-ground biomass was not related to N application whereas PE in producing essential oil (PE-oil) tended to increase with increasing levels of N applied. With regard to the effect of the cultivar, GP was less efficient in N use for oil production than MM and NFL since PE-oil of GP was lower while leaf N and PE-biomass were higher than the other cultivars. NFL was the richest in methyl chavicol but the lowest in linalool, whereas MM and GP contained linalool and eugenol.

Sweet basil (Ocimum basilicum L.) is usually cultivated for culinary purposes and sold as a fresh herb and as a dried spice. The chemical composition of basil leaves has been characterized. However, little is known on the effects of agronomical practices on leaf chemical composition. In addition, the genetic background of different cultivars may specifically interact with environmental and cropping aspects. This will eventually affect basil yield and quality. This study investigated the effects of plant density, nutrient solution strength and light intensity on two cultivars of hydroponically grown sweet basil. Napoletano and Genovese basil plants were grown in a floating system using two plant density (100 and 66 plants m-2), two different nutrient solutions (single strength Hoagland and double strength Hoagland) and two different shading treatments: 0% (control) and 50% shading (obtained by using a 50% cutoff screen). Yield components were quantified and plants were analyzed for their morphological characteristics and nutritional value.

From 1988 onwards a study was carried out to evaluate the long-term effects of increasing water salinity (O%, 0.125%, 0.25%, 0.5% and 1% of commercial NaCl) on some vegetable crops growing in a clay-loam soil. In 1992 and 1993 the effects of the residual soil salinity on yield and some aspects of yield quality were studied in lettuce, endive and fennel grown during irrigation-free seasons on a field which had undergone the same irrigation treatment since 1988. Within the range of electrical conductivity of the saturated-soil extract (ECe) between 2.0 dS m-l (treatment 0%) and 6.0 dS m-' (treatment 1%) the marketable yield decreased by about 60% in endive and fennel and by about 15% in lettuce which proved more tolerant than the other crops. Gas exchange rates and stomata1 conductance were reduced by salinity in lettuce. Soil salinity affected product quality: lettuce and endive appeared to be more sensitive to tipburn and necrotic symptoms occurring in the crop under saline-sodic conditions; fennel heart length, width, and thickness were also significantly reduced and the heart shape tended to be modified in plants grown on salt-affected plots. The results, obtained by analyzing the salt tolerance model of Maas-Hoffman and its descriptive parameters, place lettuce, endive and fennel in the moderately sensitive category. In terms of ECe, the threshold ranged from 1.8 dS m-r (fennel) to 2.7 dS m-l (lettuce) while the slope varied between 5.8% per dS m-l (lettuce) and 15.7% per dS m-r (endive).

Irrigation is a vital component of the world agriculture. It is practiced worldwide on ≈270 million hectares and it consents to produce 40% of our total food. Agricultural water consumption accounts for 70% of total freshwater use. The competition for this precious resource is increasing tremendously. Therefore, it is becoming critically important to optimize agricultural water use efficiency (WUE) defined as the ratio of crop yield over the applied water. This requires a shift from maximizing productivity per unit of land area to maximizing productivity per unit of water consumed. To maximize WUE it is necessary to conserve water and to promote maximal crop growth. The former requires minimizing losses through runoff, seepage, evaporation, and transpiration by weeds. The latter objective may be accomplished by planting high-yielding crops/cultivars well adapted to local soil and climatic conditions. Optimizing growing conditions by proper timing of planting and harvesting, tillage,...

We irrigated field-grown celery (Apium graveolens L. var. dulce [Mill.] Pers. 'Tall Utah') with four concentrations of saline water, NSC (nonstressed control), SW1, SW2, and SW3, corresponding to EC of 0.5, 4.4, 8.5, and 15.7 dS·m-1, respectively, plus a nonirrigated control (NIC) and investigated the effects of the treatments on water relations, yield and ion content. In addition, we compared simultaneously plant response to both salt and drought stress by using a modified version of the threshold-slope model. Increasing salinity of the irrigation water reduced fresh and dry weights of the shoots, but increased the dry matter percentage in shoots. The marketable yield was moderately affected by salinity (25% reduction at EC 8.5 dS·m-1). In contrast, a severe water stress dramatically decreased the marketable yield from 23 t·ha-1 (average of the irrigated treatments) to <7 t·ha-1 (nonirrigated control). Na+ and Cl- concentrations increased in salinized plants whereas nitr...

Production of vegetable crops can be limited by saline irrigation water. The variability of crop salt tolerance under different environmental conditions requires species-specific and environment-specific field evaluations of salt tolerance. Data on field performances of vegetable crops grown on soils that have been irrigated with saline water for many years are lacking. In this study we analyzed the long-term effect of irrigation with saline water on soil properties and on responses of field-grown pepper (Capsicum annuum L.) plants in these soils. Yield, gas exchanges, water relations, and solute accumulation were measured in plants grown under three different irrigation treatments: a nonsalinized control (ECw = 0.5 dS·m-1) and two concentrations of commercial sea salt, corresponding to ECw of 4.4 and 8.5 dS·m-1, respectively. In addition, a nonwatered drought stress treatment was included. Irrigation water with an EC of 4.4 dS·m-1 resulted in 46% reduction in plant dry weight (leav...

Salinization is increasingly affecting world's agricultural land causing serious yield loss and soil degradation. Understanding how we could improve crop productivity in salinized environments is therefore critical to meet the challenging goal of feeding 9.3 billion people by 2050. Our comprehension of fundamental physiological mechanisms in plant salt stress adaptation has greatly advanced over the last decades. However, many of these mechanisms have been linked to salt tolerance in simplified experimental systems whereas they have been rarely functionally proven in real agricultural contexts. In-depth analyses of specific crop-salinity interactions could reveal important aspects of plant salt stress adaptation as well as novel physiological/agronomic targets to improve salinity tolerance. These include the developmental role of root vs. shoot systems respect to water-ion homeostasis, morphological vs. metabolic contributions to stress adaptation, developmental processes vs. seasonal soil salinity evolution, residual effects of saline irrigation in non-irrigated crops, critical parameters of salt tolerance in soil-less systems and controlled environments, response to multiple stresses. Finally, beneficial effects of salinization on qualitative parameters such as stress-induced accumulation of high nutritional value secondary metabolites should be considered, also. In this short review we attempted to highlight the multifaceted nature of salinity in Mediterranean agricultural systems by summarizing most experimental activity carried out at the

BACKGROUND: The nutritional value of fresh vegetables can be affected at different steps within the field-to-market pipeline. Both pre-and post-harvest factors should be considered in order to increase the produce quality and to preserve it until final consumption. In this study the effects of sulfur nutrition during plant growth and light exposure during storage on the nutritional value of ready-to-eat friariello campano (Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort.) were studied. RESULTS: Fresh weight loss was higher in light-storage treatment. During storage, light exposure reduced leaf nitrate content, although no effect could be attributed to sulfur nutrition. Sulfur increased both lipophilic and hydrophilic antioxidant activity. The hydrophilic antioxidant activity linearly decreased during storage, whereas the lipophilic activity increased over time. However, no differences could be attributed to light exposure during storage for this parameter. Results on colorimetric indexes and their relation with the chlorophyll content are also reported. CONCLUSIONS: Ready-to-eat friariello quality may be improved with an enhanced antioxidant activity and reduced nitrate content by combining, respectively, increased sulfur availability during plant growth and exposure to light during storage. On the other hand, light exposure caused a more rapid decline in produce fresh weight during storage.

In 1994 the effects of soil salinity and top removal were studied on faba bean for green consumption, grown during the irrigation-free season on a clay-loam soil which since 1988 had undergone the same irrigation treatments of increasing water salinity (0%; 0.125%; 0.25%; 0.5% and 1% of commercial NaCl). The response to salt tolerance was evaluated by using two models: The Maas and Hoffman model Yr = 100-.S(EC,-T) and the van Genuchten model Yr = lOO/[l + (EC,/EC,,,)P]. Within the range of electrical conductivity of the saturated soil extract (EC,) between 2 dS m-' and 6 dS m-', soil salinity reduced plant height by 60%, leaf area by 70%, total above ground dry matter by 45%, mean pod weight by 15% and the number of pods per plant (48%). Leaf dry matter and specific leaf weight (SLW) were positively related to salinity. Higher salinity stress decreased the seed yield by 67% due to a reduction in weight and number of seeds, and also affected product quality. The results obtained by analysing the salt tolerance model of Maas-Hoffman and its descriptive parameters, place broadbean for green consumption in the moderately salt-sensitive category. In terms of relative yield per surface unit, from the Maas and Hoffman model the threshold value was 1.7 dS m-' and yield was reduced at the rate of 15% (dS m-')-I: the salinity level at 50% yield reduction (EC,,,) was 5 dS m-', compared to 4.7 dS m-' of the van Genuchten model. With regard to pod yield per plant, the values of parameters were 1.8 dS m-' (threshold) and 13% (dS m-' >-' (slope) and the salinity level at 50% yield reduction (EC,,,) was 5.6 dS m-', compared to 5.4 dS m-' of the van Genuchten model. Top removal at the beginning of pod set was ineffective. At low soil salinity the only effect of top removal was higher early production, indicating a more efficient partition of assimilates to growing pods and, therefore, rapid pod enlargement and higher yield at the first harvest. 0 1997 Elsevier Science B.V.

Nelle missioni spaziali, obiettivo di primaria importanza e la creazione ed il mantenimento delle migliori condizioni di vita dell’equipaggio, con particolare riferimento alla nutrizione degli astronauti. Allo stato attuale, il cibo necessario durante una missione proviene interamente dalla Terra e consiste di alimenti e bevande opportunamente trasformati e confezionati. Tuttavia, tale soluzione risulta insufficiente, sia in termini di composizione della dieta alimentare che di quantita trasportabili nelle missioni di lunga durata, ad esempio su Marte. In tale ottica, una possibile alternativa e rappresentata dallo sviluppo di sistemi per la produzione di alimenti vegetali freschi. La soia (Glycine max L.) e considerata una specie idonea alla coltivazione per tale scopo, per l’ottima qualita nutrizionale dei semi, grazie al contenuto relativamente elevato di proteine e di grassi. Tuttavia, trattandosi di una coltura tradizionalmente allevata in pieno campo, poche informazioni sono d...