High solar radiation promotes stress conditions in apple plants[Malus domestica (Suckow) Borkh.],which can be attenuated using sunburn suppressants products. Generally, the effect of sun protection agents has been analyzed using univariate techniques. The aim of the present study was to characterize, through multivariate statistical analysis, the effect of CaCO3-based sunburn suppressants on quality variables of 'Braeburn' apples. The experiment was conducted under a completely randomized design with three treatments (T=control, A=CaCO3, B=CaCO3+ZnO) and four replicates. Each treatment was sprayed four times: A, 2% w v-1; B, 5% w v-1 for the first application and 2.5% w v-1 for the three remaining ones. At harvest, sunburn degree and, in non-affected fruit, size and maturity indices were determined. Three groups (G) were distinguished. G1 consisted of T fruit and was characterized by lower fruit weight, more severe sun damage proportion of fruits, and an advanced maturity. G2 encompassed A and T fruit and showed intermediate characteristics between G1 and G3. G3 consisted of B fruit and showed higher weight, less severe sun damage, and lower maturity. Multivariate analysis allowed visualizing the effect of CaCO3-based formulations on fruit several quality variables simultaneously. We conclude that application of CaCO3 decreased severe sunburn, increased fruit weight, and delayed fruit maturity at harvest. Further research is needed to elucidate the physiological, biochemical and oxidative mechanisms mediating the effects of foliar CaCO3 applications on apple fruit.

Climatic and soil characteristics of the southwestern Buenos Aires province in Argentina make this semiarid region very conducive for olive(Olea europaea L.)cultivation. The aim of this study was to determine growth and yield of eight olive cultivars grown in three districts of the southwestern Buenos Aires province. Samples were taken in productive olives in the districts of Bahia Blanca, Coronel Dorrego and Puan in the following places: Cabildo (farm “Doña Mirta”); Faro (farm “La Susana”) and Puan (farm “Epu Antu”), respectively. During the 2015/2016 production cycle, sprout growth and plant yield were determined. The highest sprout growth was observed in the north and east cardinal points in all cultivars. In Faro, the Arbequina cultivar showed higher sprout growth in spring in the youngest trees. In Puan, the Frantoio cultivar showed greater growth than the other cultivars, which behaved similarly. Comparing different plant establishment years in the Frantoio cultivar, the highest growth was observed in the youngest trees. The Arbequina and Frantoio cultivars showed higher sprout growth (i.e., length and internode number) in spring, while the increase on basal diameter resulted higher in summer. Comparing the three study sites, the Arbequina cultivar showed greater growth in Puan than in Faro during the spring season; in summer, its growth was higher in Cabildo than in Puan. Yields and production efficiency followed the order Farga (Puan) < Arbequina (Cabildo) < Arauco (Puan) < Arbequina (Puan) ≤ Manzanilla (Puan) < Frantoio (Puan).

The production of onion bulbs (Allium cepa) requires a high amount of nitrogen. According to the demand of sustainable agriculture, the development of information and communication technologies, allows to improve the efficiency of nitrogen fertilization. In the south of the province of Buenos Aires, Argentina, between 8,000 and 10,000 hectares are cultivated per year in the districts of Villarino and Patagones. The aim of this work was to analyze the relationship of biophysical variables: leaf area index (LAI), chlorophyll content in canopy (CCC) and canopy cover factor (fCOVER) with nitrogen fertilization of intermediate cycle onion crop and its effects on yield. A trial with different doses of granulated urea and granulated urea with urease inhibitor was carried out, where biophysical characteristics were evaluated in the field and in Sentinel-2 satellite images. All variables were correlated and yield was calculated. In the field/satellite data correlation, an R2 of 0.87, 0.96 and 0.79 for leaf area index, coverage factor and chlorophyll content respectively was obtained, showing a good relationship in the three variables. The application of nitrogen in all its sources and doses produced significantly higher yields than the control. The LAI and CCC variables had a positive correlation with the yield in the months of November and December.

Argentina, one of the main South American strawberry (Fragaria x ananassa) producers, shows an increasing trend to reduce the use of agrochemicals (pesticides and fertilizers), and incorporate bio-inputs. In this context, the objective of this work was to evaluate the effect of MO.14 (a liquid organic amendment, rich in humic and fulvic acids), applied alone or combined with a biological activator (Biomix), on the yield and fruit quality of four strawberry cultivars. A trial was carried out in the 2016 productive season and part of 2017, in Famaillá (Tucumán). Treatments: MO.14 (drench), MO.14 (drench) + Biomix (foliar) and untreated control (T). Cultivars: Benicia, Camino Real, Merced and San Andreas. Yield (total fruit weight/plant, Yld), number of fruits/plant (NF), marketable fruit average weight (MFAW) and percentage of rotten fruits (%RF) were evaluated. Experimental design: CRD with three replications of 30 plants per cultivar and treatment. Data were subjected to ANOVA. Treatments improved Yld and NF, but not %RF and MFAW (genotypic effects prevailed). MO.14 showed Yld and NF values higher than MO.14 + Biomix. Treatment-cultivar interactions were significant for NF. Regarding the cultivars, Merced stood out (Yld, MFAW). In May 2017, when the first harvests of the 2nd year started, biostimulants exceeded T in Yld. Biostimulant treatments could reduce the use of chemical fertilizers in strawberry, contributing to agroecosystem sustainability, although new studies (dose, concentration, number of applications) should validate that.

In tomato (Solanum lycopersicum L.), pepper (Capsicum annuum L.) and eggplant (Solanum melongena L.) crops, there is a continuous introduction of hybrids, and it is of interest to study their adaptation to local growing conditions. The aim of this work was to characterize tomato, pepper and eggplant hybrids, according to thermal time and days from transplant required to reach flowering and fruiting between the first and fourth bunch. Crops were grown under a greenhouse located in La Plata, Buenos Aires, Argentina (34° 58´S, 57° 54´W). Tomato hybrids: Elpida and Griffy (Enza Zaden®), bell pepper hybrids: Almuden and Platero (Syngenta®) and eggplant hybrids: Barcelona (Fito®) and Monarca (Rijk Zwaan®) were planted on 08/14/2011. Air temperature and date of first flowering and fruiting from first to fourth bunches were registered. Days between transplant and start of phases and thermal time with a base temperature of 10 ºC for tomato and bell pepper and 11 ºC for eggplant were calculated. Statistical design was a randomized complete block with 4 replications. Number of days data were subjected to the non-parametric Friedman test and thermal time to analysis of variance (p<0.05). No statistical differences between hybrids were observed to reach first flowering or fruiting from first to fourth bunch, considering that under these trial conditions, the selection of these genetic materials for production can be done by different criteria than bioclimatic response.  

Sweet corn has gene in recessive homozygosis, whose function is to retard or prevent the complete transformation of soluble sugars from grain to starch, being this the main difference with the grain maize. The objective of this review is to bring together the basic concepts related to ecophysiology of sweet and super sweet corn. Botanical characteristics of maize in general and the distinctive physiological properties of sweet and super sweet corn compared to corn grain are presented. From this point, and on the review presents the main ecophysiological variables that affect the growth and development of sweet and super sweet corn. Factors affecting germination and crop growth are considered, taking into account the plant density, nutritional, water and thermal requirements, with an special focus on the effect they have on the crop physiology of the crop when they are limiting.

To determine a possible expansion of the planting calendar for petunia in northern Buenos Aires, 8 transplants of petunia Ultra White were performed throughout a year (every 45 days), in a greenhouse without climate control system in the Agricultural Experimental Station INTA San Pedro (33 ° 41’ S, 59 º 41’ WG). Air temperature and photosynthetically active radiation (PAR) were recorded every 15 minutes; photoperiod and the difference between day and night temperatures (DIF) were calculated. Duration of the complete cycle, the vegetative phase (until appearance of first visible flower), the reproductive phase (until up to 10 flowers open), the rate of progress toward flowering, plant height and dry matter accumulation were analyzed. During the year, photoperiod increased from 9.1 to 13.5 hours and average air temperature increased from 14 to 26.9°C, which resulted in a reduction of the duration of all the crop developmental phases. Increasing photoperiod caused cycle and daily dry matter accumulation to decrease linearly, the vegetative phase to decrease quadratically and the rate of progress toward flowering to increase quadratically. Flowering induction under all photoperiod and temperatures analyzed was observed. This study establishes the possibility of growing petunia Ultra White in the area throughout the year. 

Environmental factors and fertilization practices can affect the accumulation of nitrate in leafy vegetables. This research was carried out under an organic greenhouse, in the autumn - winter and spring production cycles, between 2007 and 2008 in Bajo Valle del Rio Negro, Patagonian Argentina. Various fertilizers with different doses were used, including composted bovine manure, onion-manure compost and commercial organic fertilizer. The accumulation of nitrate in leaves and petioles was evaluated. The concentration of NO-3 was related to temperature and incident solar radiation. The results indicate that organic production of spinach in the greenhouse is feasible in this region, in both crop cycles, keeping the nitrate content below the internationally established limits. The concentration of nitrate in spinach responded to the incident radiation with a correlation of -0.34 in spring and of -0.58 in autumn-winter. The highest contents were observed in periods of lower radiation during the autumn winter and lowest during spring.

The objective of this study was to analyze the agronomic performance and the grain quality of different accessions of mustard in San Pedro, Buenos Aires province. Phenology, yield components, chemical composition, and the effect of plagues and diseases were evaluated on different accessions of yellow (MA) and brown (MM) mustard. The evaluated cultivars were from Canada (Centennial and Andante), Japan (Golden and Ruby), USA (Ida Gold) and Argentina (Delfina INTA). Yields in MA are dependent on the amount of water received, the degree days, and radiation (R2 = 87.88%), while MM mustards are mainly dependent on received radiation (R2 = 88.85%). Water requirements were between 350 and 450 mm for maximum potential. Yields in San Pedro are comparable to obtained in the main producing countries. The weight of 1,000 seeds was lower than the obtained in other countries. This situation could be improved by adjusting fertilization and plant density. The observed plagues and diseases can be controlled through a proper agronomic management. The lack of registered agrochemicals for this crop by SENASA is limiting. Glucosinolate content was lower, and erucic acid content was higher than those found in mustard in other countries, while the fat acid content was the same. 

Damages by sunburn are relevant at the principal apples and pears growing regions around the world. Local assessments indicated losses of export quality apple fruits between 15 and 55 % depending on the variety, during the 2002-03 growing season, determining a substantial decline in both the quantity and quality of exportable and marketable fruit. The aim of this study was to determine the effect of black and crystal hail nets on the percentages and level of sunburn damage, the quality and performance of Chañar 90 and Pink Lady cultivars. The study was performed during two seasons in a plot located at INTA experimental station, in Río Negro province, Argentina. Intensity of solar radiation and temperature as well as fruit temperature were measured in all treatments (black and crystal meshes and control without net). The yield (kg·tree-1), size fruit distribution in different commercial categories, the rate and degree of sunburn (mild and severe) and fruit maturity indices (soluble solids, firmness, starch degradation and percentage coverage) were evaluated at harvest time. The use of black anti-hail nets and crystal in a lesser extent decreased the rate and severity of sunburn in both varieties without affecting the internal parameters of fruits quality. A higher proportion of large fruit in crystal nets was observed in both varieties, while black meshes resulted in a reduction in fruit size only in the Pink Lady cultivar.