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Vasal, S.K.

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Vasal
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S.K.
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Vasal, S.K.

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1983 - 198922000 - 20081
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Region: Global × AGROVOC: PROTEIN QUALITY ×

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Now showing 1 - 3 of 3
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    Programa de manejo, mejoramiento y utilización de germoplasma de maíz en el CIMMYT
    (CIMMYT, 1983) Vasal, S.K.; Ortega Corona, A.; Pandey, S.
    El tema de esta publicacion es el mejoramiento de la planta de maiz. Para empezar describe varios esquemas para el mejoramiento de poblaciones y luego explica el enfoque que el Centro ha adoptado en su programa de maiz. Ademas trata sobre la estructura y las actividades de las diversas unidades que componen el programa (por ejemplo, la unidad "de apoyo" que maneja el banco de germoplasma y 29 complejos germoplasmicos del Centro, asi como la unidad "avanzada que trabaja en poblaciones). La publicacion tambien describe los esfuerzos del programa por mejorar maiz para que tenga atributos especiales como la precocidad y la resistencia a enfermedades. Por
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    Stability in performance of quality protein maize under abiotic stress
    (Consiglio per la Ricerca e la sperimentazione in Agricoltura, Unità di Ricerca per la Maiscoltura, 2008) Zaidi, P.; Vasal, S.K.; Maniselvan, P.; Jha, G.C.; Mehrajjudin; Singh, R.P.
    Quality protein maize (QPM) has emerged an affordable and viable option to alleviate protein malnutrition and reduce animal feed costs, given that its grain protein contains more than double the lysine and tryptophan concentrations of normal endosperm maize. For commercial success, QPM cultivars must be competitive with normal maize in productivity and should show stable performance across environments, especially with respect to yield and protein quality traits. In the tropics, drought and low-nitrogen (N) fertility are major constraints to maize productivity. In this study, we analyze the stability of performance of CIMMYT tropical and subtropical elite QPM hybrids across stressed (drought and low N) and unstressed environments. In general, stress significantly affected all agronomic traits except male flowering. The effect was comparatively large under drought stress. Among the quality traits, grain protein, tryptophan, and lysine contents showed significant variation across environments. There was an increase in grain protein (12.7%) and in lysine (10.3%) and tryptophan contents (8.1%) under drought stress, while levels of these grain quality traits were reduced under low N by 17.0, 12.5, and 15.6%, respectively. However, the effect of stressed environments was comparatively small on protein quality traits, including tryptophan and lysine content in protein. The variation in protein quality across environments was statistically significant but largely due to genotypic variability. Variation due to environment and genotype by environment (G x E) interaction was statistically non-significant for protein quality traits, except in the case of lysine content in protein, where G x E was significant. Our results suggest that grain yield and grain protein content are the most unstable traits, whereas tryptophan followed by lysine content are the most stable, across stressed and unstressed environments.
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    A comparative study of protein changes in normal and quality protein maize during tortilla making
    (American Association of Cereal Chemists, 1986) Ortega Martinez, E.I.; Villegas, E.; Vasal, S.K.
    Protein changes were evaluated in two different maize genotypes of contrasting protein quality made into tortillas. In both types of maize, albumins, globulins, zeins, and glutelinlike components became insoluble after interacting with other biochemical entities catalyzed by the alkaline pH and the heat produced in tortilla-making. Increased nitrogen recovery with solvents having alkaline pH, a reducing agent, and sodium dodecyl sulfate indicate that hydrophobic interactions may have been involved in this change in solubility of proteins that are more easily solubilized in the unprocessed maize grain. In vitro protein digestibility with pepsin declined as nitrogen content increased in the glutelin fraction and in the residue after fractionation. Tortillas made from quality protein maize (QPM) had a superior amino acid score mainly because of their very high lysine and tryptophan content, which was not significantly affected during tortilla preparation. The superiority of the product obtained with the QPM sample was demonstrated by its high content of available lysine. Although the in sulfate indicate that hydrophobic interactions may have been involved in vitro digestibility of protein with pepsin and the amount of available lysine this change in solubility of proteins that are more easily solubilized in the changed during tortilla-making, no evidence was found of a specific unprocessed maize grain. In vitro protein digestibility with pepsin declined detrimental effect on the protein quality of the original QPM grain.
    Publication