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Bases para una nueva clasificación dimensional de la semilla Certificada de maíz para la siembra de precisión en Venezuela

2011; University of Zulia; Volume: 35; Issue: 3 Linguagem: Espanhol

2477-9407

Fausto Miranda C., Miriana Cerovich, José Díaz C., Rosana Figueroa R.,

Genetics and Plant Breeding

La clasificacion de la semilla Certificada de maiz comercializada en Venezuela fue desarrollada en 1958, y debido a la alta frecuencia de tusas conicas que caracterizaba a los cultivares disponibles, se considero solamente cuatro tipos: plano grande (PG), plano mediano (PM), plano pequeno (PP) y redondo (R). Sin embargo, en los hibridos de maiz actualmente registrados a nivel nacional predominan las tusas cilindricas, por lo cual este trabajo tuvo como objetivos caracterizar el rango de tipos de semilla en los hibridos utilizados y desarrollar una nueva clasificacion dimensional que aumente los tipos de semilla para facilitar la siembra de precision del cultivo de maiz. A partir de semilla procesada de 11 hibridos comerciales provenientes de campos para certificacion localizados en los estados Aragua y Carabobo, se tomaron muestras de 2 kg por hibrido, para clasificarlas manualmente con 12 cedazos de perforaciones oblongas y redondas de diferentes dimensiones. Los resultados mostraron que los hibridos evaluados contienen 12 tipos de semilla (2 PG, 4 PM, 3 PP y 3 R), por lo que el patron vigente de clasificacion dimensional requiere modernizacion. Para promover la siembra de precision, se propone la implantacion de una nueva clasificacion dimensional que amplie los cuatro tipos actuales de semillas a siete, detallados de la siguiente manera: un tipo PG similar al empleado actualmente, dos tipos PM retenidos por ancho (PM1 y PM2), dos tipos PP separados tambien por ancho (PP1 y PP2) y dos tipos R separados por espesor (R1 y R2). Asi mismo, para ampliar el espectro de aplicacion del patron de clasificacion descrito, se recomienda la incorporacion a mediano plazo de cuatro tipos separados por longitud: plano mediano largo (PML), plano mediano corto (PMC), plano pequeno largo (PPL) y plano pequeno corto (PPC). Palabras clave: dimensiones, maiz, semilla, tipos, Zea mays L. Basis for a new dimensional classification of Certified corn seed for precision sowing in Venezuela The classification for Certified seed of corn for trading in Venezuela was developed by 1958, and due to the high frequency of corn cobs with conic shape, available during that period, there were considered only four types: large flat (LF), medium flat (MF), short flat (SF), and rounded (R). The current generation of corn hybrids, registered in the national seed service, shows corn cobs with cylindrical shape. The objectives of this research were to characterize the seed type range of the evaluated hybrids, and to develop a new pattern of dimensional classification to increase the types of seed to promote the precision sowing practices on corn crop. By using cleaned seed of 11 hybrids harvested from field plots used for certification located at the Aragua and Carabobo states, samples of 2 kg were taken for manual screening throughout 12 different hand screens of oblongs and round perforations. The results demonstrated that hybrids tested contains 12 seed types (2 LF, 4 MF, 3 SF, and 3 R), concluding that the current classification pattern is obsolete and demands updating. In order to promote the precision planting practice, it is proposed the implementation of a new classification pattern, that increase the current four to seven types of seed as follows: one large flat (LF), two MF retained by wide shape (MF1 and MF2), two FS also classified by wide (FS1 and SF2), and two R type (R1 and R2) separated by thickness. Also, to enlarge the scope of the proposed profile of seed corn classification, it was recommended to include in the upcoming season the following four seed corn types separated by length: medium large flat (MLS), medium short flat (MSF), small large flat (SLF), and small short flat (SSF). Key words: dimensions, corn, seed, types, Zea mays L.