Rattin, J.; Valinote, J.P.; Gonzalo, R. and Di Benedetto, A. 2008. Transplant and density effects on sweet maize hybrids (Zea mays L.). Horticultura Argentina 27(62): 5-10

The aim of this work were determine both the agronomic and economic suitability of the transplant as an alternative to direct seeded and the effect of three plant densities (4, 8 and 12 plants·m-2) on light penetration and light utilization in view to optimize plant and crop productivity for two sweet maize hybrids mutants (Canner and Butter Sweet). The experiments were conducted at the INTA Balcarce Experimental Station, Argentina (37º 45’ S; 58º 18’ W and altitude 130 m) during the 2004/2005 and 2006/2007 growing seasons on a typic argiudol soil. A factorial experimental design was used. Our results showed (a) that transplant change dry weight accumulation, increased light interception, the harvest index, the radiation use efficiency and yield; (b) optimal plant density would be increased near 12 plants·m-2 although daily maximum and minimum temperature during the first stages of vegetative growth must be considered and (c) when plant density and prices increased, transplant would be an acceptable alternative.

López, A.E.; Burgos, A.M. and Cenóz, P.J. 2008. Incidence of a growth regulator and a rooting media over the vegetative propagation in Ocimum selloi Benth. Horticultura Argentina 27(62): 11-15

Ocimum selloi Benth. is a medicinal plant because the characteristics of its essential oils. This species is either cultivated at home gardens or simply collected from wild population and it is commonly known as “field anise”. This research was curried out in Corrientes Province, Argentina; the aim was to evaluate the influence of a plant growth regulator, the anaftalen acetic acid (ANA), in different rooting media (superficial soil sterilized by hot temperature and an inert mixture of perlita and vermiculita) over the vegetative propagation of O. selloi as a profitable production technique. The rooting percentage, the number of roots per cutting, the total roots length (in cm) and the percentage of sprouting cuttings were evaluated in three opportunities 10, 20 and 30 days after the cuttings were planted. It was used in an experimental design of randomized blocks with four repetitions by treatment. The results were evaluated with a variance analysis (ANOVA) and a Tukey's test (a = 0.05). The use of ANA, in arrangement with the inert substrate, improves all the factors considerate and therefore the plant staff.

García, M.; Alfonso, W.; Cirera, I. and Curioni, A.O. 2008. Seed yield and quality on parsley (Petroselinum crispum L.). Effect of nitrogen rates. Horticultura Argentina 27(62): 16-19

Parsley, (Petroselinum crispum L.) is cultivated for fresh or dehydrated leaves, although grain production could be an important alternative for seed production or for distillation to obtain essential oil. The experiment was carried out at Luján University (34º 36' S; 59º 7' W), and was sown on May 3rd 2005 at the rate of 12 kg·ha-1. Treatments were: 0, 25, 50 and 75 kg·ha-1 of N with a Complete Randomized Design with 3 replications.

Harvest occurred 270 days after planting in 5 plants of two central rows of the beds. We evaluated height, number of branches and number of umbels per plant. Main umbels were harvested and threshed separately from secondary umbels. Seeds were sorted by size from each part, germination and weight of 1,000 seed recorded for each one.

Data was analyzed by SPSS. There were not significant differences between treatments on height, and average values were between 1,00 and 1,05 m. N fertilization rates showed higher number of branches than non-fertilized treatment, although no significant differences were found (8.89 and 7.33, respectively). No significant differences were found for secondary umbels. There were significant differences between N rates for the seed yield: 3.405,16 kg·ha-1 (average between 0-25 kg·ha-1 of N) and 6.478,75 kg·ha-1 (average between 50-75 kg·ha-1 of N). Nitrogen rates explained 68 % of increasing yield. Seed yield was more influenced by the number of secondary umbels.

Burba, J.L. 2008. The garlic varieties groups (Allium sativum L.). Contribution for understanding. Horticultura Argentina 27(62): 20-27

The results of the natural selection, the popular and commercial denominations, the genetic creations and the intents of containing the varieties of garlic, they have given place to interpretation confusions when of comparisons it is. The idiomatic barriers and the errors in the translations also contributed to such a confusion. Many students and investigators find it complex to interpret the results when these they are compared with experimental works of other countries. In this revision work its puts on in consideration the error sources and the interpretations of certain texts, by the light of the available information.

Portela, J.A. 2008. Weed control in vegetable crops: is it a question of factors or a question of processes? Horticultura Argentina 27(62): 28-34

Nowadays, on vegetable growers' rationality it is firmly established the idea that weeds are an adverse factor for the crop, and to avoid important yield losses they must be eradicated. Their control is being made only by weeding practices, mechanically or manually, as well as by herbicides applications. Particularly, the introduction of herbicides into agriculture radically shifted the perception of those plant populations accompanying the crop. They are currently considered just a secondary problem with a relatively easy solution rather than an important component of the agroecosystem. This vision, however, implies great limitations; because considering weeds like a factor to cancel out in a productive equation reduces the grower attention just to the current crop, loosing what is taking place on time in the agroecosystem as a whole. To implement actions compatible with sustainability a different approach to the problem is needed, integrating weeds to the crop management from a systemic rather than a factorial-deterministic focusing; keeping in mind their role and dynamic into the agroecosystem, on space as much as on time. Weed control in vegetable crops must then be taken as a question of processes and what that involves is discussed here.