Fundamentación del conjunto tractor-apero para la labor de surcado y su influencia en el consumo energético en cultivos de raíces y tubérculos

El cumplimiento de los objetivos agrotécnicos de los cultivos de raíces y tubérculos exige que la labor de surcado configure un caballón que permita el trabajo de los posteriores aperos que participan en las demás labores de cultivo. En la agricultura cubana se emplean diversos tipos de surcadores que difieren en las características de los elementos aporcadores. Este hecho afecta a la capacidad de trabajo del conjunto tractor-apero y por extensión en el consumo de combustible y el rendimiento del cultivo. El objetivo de este trabajo ha sido fundamentar el empleo del apero más adecuado para la labor de surcado en cultivos de raíces y tubérculos (patata, boniato, yuca) en Fluvisoles, teniendo en cuenta el comportamiento de las dimensiones y forma del caballón, cualidades tecnológicas explotativas del conjunto tractor-apero, consumo energético del proceso productivo y el rendimiento agrícola. Los tratamientos considerados estuvieron determinados por la utilización del surcador fertilizador IIMA-BALDAN 4.500 (T1), y los surcadores aporcadores SA-5 (T2) y SA-3 (T3). En los tres tratamientos se alcanzó un perfil de la sección transversal del caballón de configuración cóncavo-convexo. El surcador BALDAN logró el mejor comportamiento de los indicadores tecnológico-explotativos lo que se tradujo en la mayor capacidad de trabajo de 1,36 ha h-1 y el menor consumo de combustible de 5,38 L ha-1. Este mismo tratamiento proporcionó el mayor rendimiento medio de los cultivos superando en un 43,2% al del surcador SA-5 y en un 57,9% al del surcador SA-3. Desde el punto de vista energético T1, obtuvo una mejor eficiencia energética superior en un 43,5% a la del tratamiento T2, y en un 57,1% a la del tratamiento T3. ABSTRACT The achievement of agrotechnical objectives in the cultivation of roots and tubers demands the plow through activity creates a ridge to allow the work of subsequent farming tools participating in other cultivation works. In Cuban Agriculture various kinds of furrowers are used which differ in the characteristics of their earth up elements. This fact affects work capacity of the tractor-farming tool combination and by extension to fuel consumption and cultivation yield. The aim of this work has been to support the use of the most accurate farming tool in the plow through activity for the cultivation of roots and tubers (potato, sweet potato, cassava) in Fluvisoils, taking into account the behaviour of the ridge´s dimensions and shape, technologic-explotative qualities of the tractor-farming tool combination, energy consumption of the productive process and agricultural yield. The treatments considered were determined by the use of fertlizing furrower IIMA-BALDAN 4.500 (T1), and the earth up furrowers SA-5 (T2) and SA-3 (T3). During the three treatments a transverse section profile of the ridge under concave-convex configuration was obtained. The furrower BALDAN achieved the best behaviour of the technologic-explotative indicators, which was translated into the largest work capacity of 1,36 ha h-1 and the smallest fuel consumption of 5,38 L ha-1. This treatment also provided the biggest average yield of the cultivation, overcoming in a 43,2% the furrower SA-5 and furrower SA-3 in a 57,9%. From the energetic point of view T1 gained better energetic efficiency than treatment T2 in a 43,5% and treatment T3 in a 57,1%.

Nonsteroidal moulting hormone agonists: effects on protein synthesis and cuticle formation in colorado potato beetle larvae.

Larvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say), that were orally treated with RH-0345 at 0.1 mg l?1, RH-5849 at 10 and 50 mg l?1, tebufenozide at 2 g l?1, and 20-hydroxyecdysone at 2 g l?1, showed symptoms of prematuremoulting, followed by inhibition of ecdysis. In addition, fresh weight gain and total protein content were blocked. The effects on haemolymphal and cuticular polypeptides after PAGE were linked with premature, new epicuticle deposition as was observed under the electron microscope. These observations support the concept that the ecdysteroid-mimicking action of the three nonsteroidal molecules is specific

First Report of Homothallic Isolates of Phytophthora infestans in Commercial Potato Crops (Solanum tuberosum) in the Toluca Valley, Mexico

Phytophthora infestans causes severe symptoms of wilt disease on potato crops (Solanum tuberosum) in the Toluca Valley (Mexico)despite the use of fungicides. P. infestans oospores produced by sexual reproduction can survive in the soil for many years, resisting harsh environments.

Sensory and texture properties of mashed potato incorporated wigh inulin and olive oil blends

The effect of adding different ratios of inulin and extra virgin olive oil blends, formulated without (MPA) and with cryoprotectants (MPB), on texture properties of fresh mashed potatoes and frozen/thawed mashed potatoes was studied. Inulin and extra virgin olive oil behaved like soft ?llers, but inulin was associated with increased?brousness and extra virgin olive oil with increased creaminess. In the total dataset and frozen mashed potatoes, frozen/thawed mashed potatoes, and MPA subgroups, component 1 was a contrast between mechanical and surface textural attributes, whereas in MPB samples component 1 was determined by geometrical attributes. Addition of inulin at 30 g/kg and extra virgin olive oil at 45 g/kg is recommended.

Texture perception determined by doy protein isolate and inulin addition in potato puree: links with mechanical and microstructural features

This study evaluated the effect of adding soy protein isolate (SPI) and long-chain perception, trained and untrained panel inulin (INL) blends with 10 different SPI : INL ratios on the textural, rheological and 17 microstructural properties of freshly made and frozen/thawed potato puree. All the potato puree samples were subjected to a sensory texture pro?le analysis and a 21 trained panel rated the intensity of six descriptors, while an untrained panel did the same on six selected frozen/thawed products. The main SPI : INL ratio effect remained signi?cant for all the descriptors evaluated, when the analysis of variance was applied considering the untrained assessors as random effects. However, only trained panel scores for creaminess corresponded well with untrained assessor. Rheological ?ow index values were linked with variations in perceived consistency, and geometric and surface textural attributes were explained by structural features such as the presence of INL crystallites and SPI coarse strands.

Transcriptional changes and oxidative stress associated with the synergistic interaction between potato virus X and potato virus Y and their relationship with symptom expression.

Many virus diseases of economic importance to agriculture result from mixtures of different pathogens invading the host at a given time. This contrasts with the relatively scarce studies available on the molecular events associated with virus---host interactions in mixed infections. Compared with single infections, co-infection of Nicotiana benthamiana with Potato virus X (PVX) and Potato virus Y (PVY) resulted in increased systemic symptoms (synergism) that led to necrosis of the newly emerging leaves and death of the plant. A comparative transcriptional analysis was undertaken to identify quantitative and qualitative differences in gene expression during this synergistic infection and correlate these changes with the severe symptoms it caused. Global transcription profiles of doubly infected leaves were compared with those from singly infected leaves using gene ontology enrichment analysis and metabolic pathway annotator software. Functional gene categories altered by the double infection comprise suites of genes regulated coordinately, which are associated with chloroplast functions (downregulated), protein synthesis and degradation (upregulated), carbohydrate metabolism (upregulated), and response to biotic stimulus and stress (upregulated). The expressions of reactive oxygen species?generating enzymes as well as several mitogen-activated protein kinases were also significantly induced. Accordingly, synergistic infection induced a severe oxidative stress in N. benthamiana leaves, as judged by increases in lipid peroxidation and by the generation of superoxide radicals in chloroplasts, which correlated with the misregulation of antioxidative genes in microarray data. Interestingly, expression of genes encoding oxylipin biosynthesis was uniquely upregulated by the synergistic infection. Virus-induced gene silencing of ?-dioxygenase1 delayed cell death during PVX?PVY infection.

Jasmonate-dependent modifications of the pectin matrix during potato development function as a defense mechanism targeted by Dickeya dadantii virulence factors

The plant cell wall constitutes an essential protection barrier against pathogen attack. In addition, cell-wall disruption leads to accumulation of jasmonates (JAs), which are key signaling molecules for activation of plant inducible defense responses. However, whether JAs in return modulate the cell-wall composition to reinforce this defensive barrier remains unknown. The enzyme 13-allene oxide synthase (13-AOS) catalyzes the first committed step towards biosynthesis of JAs. In potato (Solanum tuberosum), there are two putative St13-AOS genes, which we show here to be differentially induced upon wounding. We also determine that both genes complement an Arabidopsis aos null mutant, indicating that they encode functional 13-AOS enzymes. Indeed, transgenic potato plants lacking both St13-AOS genes (CoAOS1/2 lines) exhibited a significant reduction of JAs, a concomitant decrease in wound-responsive gene activation, and an increased severity of soft rot disease symptoms caused by Dickeya dadantii. Intriguingly, a hypovirulent D. dadantii pel strain lacking the five major pectate lyases, which causes limited tissue maceration on wild-type plants, regained infectivity in CoAOS1/2 plants. In line with this, we found differences in pectin methyl esterase activity and cell-wall pectin composition between wild-type and CoAOS1/2 plants. Importantly, wild-type plants had pectins with a lower degree of methyl esterification, which are the substrates of the pectate lyases mutated in the pel strain. These results suggest that, during development of potato plants, JAs mediate modification of the pectin matrix to form a defensive barrier that is counteracted by pectinolytic virulence factors from D. dadantii.