Crop In Spain Research Articles

Spanish Chestnut Cultivars

Chestnut (Castanea sativa Mill.) is an important crop in Spain. This inventory of chestnut cultivars complements previous studies. We have located 152 chestnut cultivars in 131 municipalities covering 108.6 ha, with 72 new cultivars in addition to the 80 previously found. Fewer than 50% of these cultivars are extensively cultivated. Chestnuts in Spain are grown from sea level to 1100 m, but are more frequent between 200 and 800 m on northern-facing slopes. Most of the chestnuts are harvested from 25 Oct. to 10 Nov.

Molecular and insecticidal characterization of a Bacillus thuringiensis strain isolated during a natural epizootic.

A new Bacillus thuringiensis strain belonging to the serovar aizawai was isolated from a dead larva of the lepidopteran Mythimna loreyi collected in a corn crop in Spain during a natural epizootic. This strain, which was named Leapi01, was compared with the kurstaki and aizawai strains isolated from Dipel(R) and Xentari(R), by electron microscopy, SDS-PAGE, plasmid pattern, PCR and insecticidal activity. This strain showed similar morphological and biochemical characteristics to the standard strains. The content in cry genes of Leapi01 was analysed with a set of general and specific primers recognizing most of the cry genes reported to date. DNA amplification was obtained with primers corresponding to six genes and, to clearly determine the identity of the genes, the amplified fragments were sequenced and corresponded to cry1Aa, cry1Ab, cry1Ca, cry1Da, cry2Ab and cry1Ia. However, the proteins encoded by two of these genes, Cry2 and Cry1I, were not detected in the SDS-PAGE of the purified parasporal bodies. The insecticidal activity of Leapi01 was determined by bioassays against two Lepidoptera species, Helicoverpa armigera and Spodoptera littoralis, that were found to be very susceptible to Leapi01 purified crystals. Since two of the cry genes identified in Leapi01 appear to be silent, other factors may be involved in the toxicity of the strain. As a result of this study, the potential of Leapi01 as biological control agent is discussed, with special emphasis on the high toxicity and relatively broad spectrum activity compared with two B. thuringiensis strains that are the active ingredients of commercial preparations commonly used as bioinsecticides.

Mechanical Harvesting of Paprika Peppers in Spain

Paprika pepper is a traditional crop in Spain. Unfortunately, it is labour intensive and increasing manpower costs, relative to the product value, are such that the crop is now economically unattractive. Harvesting is the operation that requires most hand work, thus it is the most interesting to mechanize. Pepper harvesters already exist, but it was necessary to find one that was able to harvest the varieties of paprika pepper that are grown in Spain.At first, green bean harvesters were tried, but these were not suitable to work with Spanish varieties of peppers. Similarly, an American open helix harvester used in Murcia (Spain) was also found to be unsatisfactory. As a result of these negative experiences, an experimental prototype paprika pepper harvester was designed and built in 1992, adapted to Spanish conditions. A commercial harvester was constructed in 1993 and this tested in the three main paprika pepper production regions of Spain, namely, Murcia, Extremadura, and Valle del Ebro from 1993-1995.With the variety “Negral”, 89 to 95% of the production was collected with 4 to 11% trash, depending on the state of the crop and harvesting dates. With another widespread variety “Ocal ”, 90 to 93% of fruits were recovered, with 1 to 7% trash. All these results were obtained when the crops were in the best condition. These results are economically interesting, and can be obtained if farmers give more attention to cultural practices that favour mechanical harvesting, such as straight rows, plants with the fruits as high over the soil as possible, and avoid stones, clods and other obstacles that can be collected by the harvester.

Phenological stages of the pomegranate tree (Punka granatum L.)

Summary.As in other temperate species, the pomegranate tree shows different phenological characteristics through its vegetative cycle in response to changing temperature. This phenology has been studied as a basis for comparisons of the successive stages of growth and reproduction in different geographical areas and conditions. The variety Mollar de Elche was studied, since it is grown on more than 95% of the total area devoted to this crop in Spain. Thirteen phenological‐stages were identified during the annual cycle, starting at bud in dormancy and finishing a year later with leaf fall. These stages are denoted using the BBCH General Scale which uses numerical codes to represent particular stages. The code uses a two‐digit number to describe the different phenological states and makes it possible to distinguish between principal and secondary stages of development. The duration of stages was measured in days and as accumulated degree‐day.

Euphorbia lathyris as an energy crop—Part 1. Vegetative matter and seed productivity

Euphorbia lathyris is being evaluated as an energy crop in Spain. Preliminary experiments have been carried out varying the date of sowing (autumn and spring), sowing density (36 000, 100 000 and 143 000 plants ha −1), irrigation and nitrogen application. Dry matter yields varied from about 2500 to 20 000 kg per hectare, depending on the treatment. As an alternative to vegetative matter production, seeds can yield between 1500 and 2500 kg ha −1 containing 48% of oil that could be used for industrial purposes.