Heterosis x environment interaction in maize what drives heterosis for grain yield?
Variation in mean heterosis over a range of environments is expected when maize hybrids and inbred lines respond differently to environmental stimuli. However, the magnitude and nature of the heterosis x environment interaction [H x E] has not been adequately described. The objectives of this work w...
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| Otros Autores: | , , , , |
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| Formato: | Artículo |
| Lenguaje: | Inglés |
| Materias: | |
| Acceso en línea: | http://ri.agro.uba.ar/files/intranet/articulo/2011Munaro2.pdf LINK AL EDITOR |
| Aporte de: | Registro referencial: Solicitar el recurso aquí |
| Sumario: | Variation in mean heterosis over a range of environments is expected when maize hybrids and inbred lines respond differently to environmental stimuli. However, the magnitude and nature of the heterosis x environment interaction [H x E] has not been adequately described. The objectives of this work were to determine [i] the effects of environmental variability on the expression of heterosis for plant grain yield [PGY] and related ecophysiological traits and [ii] to what extent H x E is of general importance for the expression of heterosis for these traits. Field experiments included a set of six inbred lines and twelve derived hybrids grown in 14 environments [year x nitrogen x water regime combinations] in the temperate region of Argentina. Main physiological and quantitative determinants of PGY were measured and mid parent heterosis [MPH] computed for each trait. Genotype x environment interaction was investigated using the joint regression analysis. For PGY, hybrids had a significant but moderate association between sensitivity to the environment and mean genotype value, whereas inbred lines did not show association. For harvest index [HI] hybrids showed greater mean values than inbreds, however, regression coefficients of both genotype groups tended to overlap slightly. A decrease in environmental quality led to a decline in the expression of heterosis for PGY but not for HI. A bilinear with plateau model adequately described the association between heterosis for PGY and environmental quality, because a threshold value was detected beyond which further increases in environment mean did not translate into higher heterosis for PGY. A similar response pattern was found between PGY MPH and biomass at physiological maturity [BiomassPM] MPH. Despite the greater heterosis for BiomassPM, further increases in PGY MPH could not be realized above a threshold value of 115gpl-1 for BiomassPM MPH. HI MPH was the major factor that set a limit to PGY MPH under favorable environments. |
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| ISSN: | 0378-4290 |