|Dos santos, N|
|Prior, Stephen - Steve|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/10/2009
Publication Date: 8/10/2009
Citation: Ferreira, C.F., Dos Santos, N.Z., Valaski, J.C., Motta, A., Prior, S.A., Reissmann, C.B., Gabardo, J. 2009. Diagnose Nutricional de Cultivares de Milho (Zea mays L.) de Diferentes Níveis Tecnológicos. In: Proceedings of the XVII Reuniao Brasileira de Manejo e Conservacao do Solo e da Agua no Contexto das Mudancas Ambientais, August 10-15, 2008, Rio de Janeiro, Brazil. P. 5. Interpretive Summary: Corn genetic selection can influence not only yield potential but yield quality. Nutritional characteristics (leaf, stem, and grain) of varieties representing five technological levels used in Brazil were evaluated (i.e., local cultivars, improved varieties, double, triple and simple hybrids ). In general, the concentration of nitrogen and phosphorus was higher in grain but K was higher in non-yield tissue. Genetically improved cultivars were shown to have reduced N, P, and K in non-grain parts suggesting more movement of nutrients to grain. Findings suggest that genetic improvement programs have not only changed yields but have also led to improved grain nutritional quality.
Technical Abstract: The introduction of hybrids has contributed to increases in grain production. However, there is little work examining the relationship of genetic improvement to nutrient use efficiency, concentration, and export. The objective of this study was to evaluate changes in nutritional status of five maize technology levels (i.e., local cultivars, improved varieties, double, triple and simple hybrids ) by using two examples of each level. The experimental design was a randomized block with five replications. At harvest, fifteen whole plants were collected from the two central rows of six row plots and separated into grain, leaf, and stalk fractions. Tissue N was determined by dry combustion using an CN2000 analyzer while P and K of ashed tissue (successively dissolved in 1 N HNO3 and 1 N HCl) was measured using inductively coupled plasma spectrophotometry. There were statistical differences regarding N, P, and K between levels of technology evaluated. The concentrations of N and P were higher in grain while the K concentration was higher in stalks followed by leaves. As a result of genetic improvement programs, N, P and K of high technological level cultivars have lower concentrations in non-yield fractions, indicating more efficient nutrient translocation to grain. This implies improvements not only to production and yield but also to the nutritional quality of grain.