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Agriculture in arid regions requires physiological and agronomic studies. Phenology was analysed and morphological and productive responses of garlic (cv. Morado INTA) to irrigation strategies were evaluated in an arid region of La Rioja. The trial was carried out in INTA EEA Chilecito in 2022. The design was a randomized complete block design with three replications and three irrigation treatments were applied: T1-100%, T2-120% and T3-75% of crop evapotranspiration (ETc) during 28 days after the 12th visible leaf of the main growth stage 1(main shoot).The extended garlic phenological scale was used. Leaves, plant height, plant pseudostem and neck, basal disc, diameter, height and bulb weight were measured. Phenology results: 97.8% sprouting at 19 dap (days after planting) and 368 growing degree-days (GDD), main shoot development (12th leaf) at 142 dap and 1823 GDD and the 100% bulb diameter at 212 dap and 3095 GDD. Irrigation results: T3 did not affect height, number of leaves or pseudostem length, but modified the basal leaf with respect to T1 and T2. T3 reduced neck diameter and bulb height without affecting final bulb weight, and consequently increased the bulbification index with respect to T2. The application of controlled deficit irrigation (75% of ETc) during the month of September and the return to full irrigation until bulb harvest are strategies that optimize water use and production in the garlic crop (cv. Morado INTA).

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Variation in weather elements affects the production of agricultural crops. Air and soil temperature control plant growth and development, as is the case in garlic (Allium sativum L.). The objective of the study was to evaluate the phenology and productive characteristics of two garlic cultivars according to air and soil temperature during 2022, at the Tilimuqui Experimental Field of INTA EEA Chilecito. The experimental design was Randomized Complete Blocks with three replications. The extended phenological scale of garlic was used. Soil temperature was measured at 5 cm and 15 cm depth and meteorological data recorded by the automatic weather station located at the trial site were used. Height, number of leaves, bulb weight and parameters for calculating the bulbification index were measured. For the same growing conditions, from planting date (both on 11/04/22) they showed different percentages of sprouting, number of leaves and bulb weight. The cv. Morado INTA required a heat summation of 3095 GD and a cycle of 213 days until harvest (09/11/22) and the cv. Nieve INTA required a heat summation of 3397 GD with a cycle of 225 days until harvest (21/11/22). The two cultivars had average photoperiods of 12.2 h in June and 14.5 h in November.

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Rhaphithamnus spinosus is an evergreen, thorny shrub with violet flowers and violet colored nucleus fruit; endemic from the north of the Andean Patagonian forest. Previous works indicate that the seeds have a physiological and mechanical dormancy in their fruit. The objective was to evaluate the methods for sexual and asexual propagation of the species. The viability of the seeds was analyzed with a germination and 2,3,5-triphenyltetrazolium tests. Four pre-germination treatments were tested: T1: Cold-wet stratification for 60 days, (T2): Scarification with sandpaper + cold-wet stratification-60 days, T3: Scarification with sandpaper + soak 1000 ppm gibberellic acid (GA3) for 24 hs and T4: Scarification with sandpaper + soak water / 24 hs as a control in two seed samples. Seeds were sown at 18 °C, with a photoperiod of 12 hours and subsequently sown in a multicell tray. The agamic method consisted in hardwood cuttings that were cut during autumn, and placed in multicell trays, treated with a 1500 ppm indole-3-butyric acid (IBA) solution, with basal heating (20 ºC±2) and mist. In sexual propagation, the germination percentages per treatment were: T1: 4.81 %, T2: 6.29 %, T3: 47.78 % and T4: 2.59 %. Growth in height and ramifications were analyzed. Asexual propagation reached 96 % rooting at 90 days, and plants were then transferred to 3 L pots. It is concluded that the application of combined pre-germination treatments improves the germination percentage. These resultssuggest the possibilityfor professional propagation and container cultivation.

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Onion (Allium cepaL.) is one of the main horticultural species in Argentina. The supply of seeds of this species is mainly from national production. Gibberellic acid (AG3) in onion is effective to induce flower buds when applied before or during the period of low temperatures.Throughout three seasons in La Consulta, Mendoza, Argentina, AG3 was tested to determine its effects on the seed production of onion cv Valcatorce INTA using the seed-to-seed method. The treatments were 0-200-400-600 mg.L-1 of AG3 in the first season and 0-300-600-900 mg.L-1 of AG3 in the other two; the plants were sprayed when they had between 5 and 7 leaves.The design was complete blocks with random plots and five replications. The number of umbels per plant, the seed yield per plant and unit area, and the seed quality, were determined. Gibberellic acid increased the number of umbels per plant.In the first two seasons, the highest seed yield per unit area was achieved with the use of the highest dose of AG3. However, in the third season, the best performance was obtained with 300 mg.L-1. The application of AG3 with the highest doses tested decreased the weight of a thousand seeds in two seasons without impairing germination.

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This work aimed to evaluate the dormancy intensity of reproductive and vegetative buds of ‘SCS444 Nicoleto’ peach cultivar, in different months, in an orchard located on the southern coast of the state of Santa Catarina, Brazil. One-year old branches of adult plants were collected in the middle of March, April, May, June and July and submitted to 0, 150, 300 and 450 chill hours below 7.0 oC, with subsequent forcing to 25.0 oC. The percentage of branches with open flower, lateral and terminal vegetative buds and the average time for sprouting (TMB) of the first open bud of each type were recorded. Without supplementary chill, all types of buds presented a decreasing TMB with average values ​​from 29 to 7 days from March to July, with the reproductive buds presenting a lower TMB than the lateral vegetative buds in all months. The most intense endodormancy was recorded in the month of May. From the results obtained, a simplified typification of the hibernal rest period in the year analyzed was suggested, with a paradormancy/induction phase being followed by an endodormancy phase and, finally, ecodormancy. Full bloom in the experimental orchard took place on July 25th, ten days before vegetative sprouting. This anticipation of flowering may be related to two phenological characteristics observed in this work: the more superficial endodormancy of reproductive buds and their lower heat requirement during ecodormancy.

PDF 636.7 KB (354 downloads)

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.

PDF 610.4 KB (737 downloads)

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. 

PDF 598.4 KB (844 downloads)

Propagation of native species for ornamental or medicinal purposes has gained importance in recent years. Rhodophiala mendocina has flowers with ornamental interest, and bulbs that produce the alkaloid galantamina used as palliative to treat Alzheimer disease. The objective was to propagate R. mendocina testing different treatments. Seeds were collected from natural populations, disinfected with ethanol (70%), washed and placed on paper in a germination chamber. The percentage of germinating seeds was determined according to a completely randomized design with four replicates per treatment (35 to 25 °C, 30 to 20 °C, 25 to 15 °C and 20 to 10 °C, with 16h of photoperiod). The results showed that the seeds of R. mendocina exceeded the percentage (50% of germination) with the 25 to 15 ° C treatment, and the other treatments presented significantly lower values. On the other hand, to test agamic propagation, three treatments were applied: (1) complete bulb as a control, (2) bulb quarters and (3) twin scales.The external scales were removed for disinfection (idem to seeds), and fungicide was added (1 gl-1 of Captan). External scales were placed in containers with substrate, and kept in growth chambers (photoperiod 16 hs light / 25 ° C and 8 h darkness / 20 ° C).The results showed a higher percentage of survival for the control and a greater multiplication for the quarter treatment.

Application of auxin regulators:

effect on fruit set in tomatoes for fresh market.

HORTICULTURE | Martinez, S. - Garbi, M. - Carbone, A. - Morelli, G. - Argerich, C. - Pacheco, R. - Puch, L.

Tags: Solanum lycopersicum - auxins - production – yiel - hormone

PDF 401.5 KB (4282 downloads)

With the aim of evaluating the effect of β-naftoxiacetic acid doses and application moment on characteristics and yield of tomato fruits, three trials were carried out in La Plata (Buenos Aires), one in Bella Vista (Corrientes) and one in Peña Colorada (Salta). La Plata: 1) control (without hormone, with water), hormone [cm3.litre-1]: 2.5 (start of flowering) and 5 (temperature below 13°C or from the fourth cluster). With 5 cm3.litre-1, applied from the fourth cluster, fruit diameter increased; 2) control (without hormone or water), hormone: 2.5 and 5 cm3.litre-1 from start of flowering. Both doses significantly increased size and percentage of hollow fruits; 3) control (without hormone, with and without water), hormone: 1, 2.5, 3.5, 5, 7.5 and 10 cm3.litre-1 from start of flowering. Fruit fresh weight increased with 3.5 and 10 cm3.litre-1, in contrast to control with water; fruit dry weight was higher with 3.5 cm3.litre-1, compared to both controls and with 1 cm3.litre-1; hollowed fruits increased with doses over 3.5 cm3.litre-1, compared to controls and with 10 cm3.litre-1, respect to doses below 3.5 cm3.litre-1. Bella Vista: control without treatment, hormone: 3 and 5 cm3.litre-1 (flowering); without differences among treatments. Peña Colorada: controls (without hormone, with and without fruit pruning), hormone [cm3.litre-1]: 5, without fruit pruning and 7.5 with fruit pruning. Fruit weight was higher with 5 cm3.litre-1 (3th and 5th cluster).  

PDF 444.6 KB (492 downloads)

In recent years the cultivation of white mustard (Sinapis alba) has been promoted as a winter alternative crop in the Pampas. Previous studies related to mustard entomofauna, denote the presence of Microtheca ochroloma, a specific chrysomelid of Brassicaceae family, causing significant defoliation. The objectives of this study were to evaluate whether the presence of M. ochroloma varies according to different genetic materials and white mustard phenological stages and describe some parameters of its life cycle feeding on this crop. The studies were carried out in the Experimental field and Laboratory of Agricultural Zoology of Universidad Nacional de Luján. Genetic materials of different origins of white mustard, were sampled weekly in the number of plants infested with larvae and adults of M. ochroloma during a growing season. The development cycle was studied under laboratory conditions (24 ± 2 ºC, 60 ± 10 % RH, photoperiod 10L: 14O) from a cohort of eggs. The larvae were fed with the origin Canada and recorded development time of each stage. Pupae were sexed and then formed pairs to estimate the pre-oviposition period and fecundity for 30 days. Both larvae and adults were recorded in all genetic material, although the number of infected plants showed no significant differences between origins and between phenological stages. The average cycle length was 29.1 days. Females oviposit a mean of 74.9 eggs into several groups. These results suggest that M. ochroloma interchangeably used as a food source to all genetic material evaluated and successfully completes its life cycle feeding on S. alba.