Direct and correlated responses to recurrent selection for prolificacy in maize at two plant densities
Maize (Zea mays L.) breeding depends on the enhancement of desired genetic parameters through selection and the selection environment influences these parameters. Breeders usually select at only one plant density. Breeding program progress, however, may be limited by this practice. Our objectives we...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 1998 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/46208 |
| Acceso en línea: | http://hdl.handle.net/10261/46208 |
| Access Level: | acceso abierto |
| Palabra clave: | Zea mays L. Genetic parameters Plant density Yield Yield components Prolificacy |
| Sumario: | Maize (Zea mays L.) breeding depends on the enhancement of desired genetic parameters through selection and the selection environment influences these parameters. Breeders usually select at only one plant density. Breeding program progress, however, may be limited by this practice. Our objectives were to evaluate the environmental influence on selection efficacy for prolificacy through selection at 60,000 and 30,000 plants ha-1, and to test other indirect selection criteria to improve yield. Synthetic variety AS-Z and three cycles of S1 recurrent selection for prolificacy in AS-Z were tested with the same density rates at two Spanish locations in 1991 and 1994. Therefore, four experiments were considered: two selection experiments with one at high and one at low density, and two evaluation experiments at high and low-plant density. Direct selection for prolificacy was effective. Prolificacy increased in both plant-density-selection experiments at an average rate of 0.077 ears plant-1 cycle-1 (P less than or equal to 0.01) when selecting with high-plant density, and an average of 0.026 ears plant-1 cycle-1 (P less than or equal to 0.05) when selecting with low-plant density. Total genetic gain for three cycles of selection averaged over evaluation experiments was nearly 20% at the high-plant density and approximately 6% at the low plant density compared with the non-selected AS-Z variety. Negative quadratic responses at the low-density selection experiment existed, but the response was highly significant linear for the 60,000-plant-ha(-1) selection experiment. Yield did not show a significant correlated response to selection for prolificacy, but in three of the four instances, prolificacy and yield had the same trend. The high-plant density was the best environment to improve yield components and other agronomic characteristics of AS-Z. Selection for only prolificacy did not produce undesirable effects, but more information is needed to assess the effects of indirect selection. |
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