Low nitrogen tolerance in tropical quality protein maize (Zea mays L.): value of predictive traits
In the tropics, maize (Zea mays L.) is often grown under low N conditions. Information on the respective role of N uptake and partitioning at anthesis in determining grain yield under low N is scarce. Senescence traits have been proposed as secondary traits to select for low N tolerance, but the stability of their association with yield under different environmental conditions has been rarely described. In the present study we analyzed the associations between grain yield, N uptake and partitioning at anthesis, dry matter matter partitioning, and senescence traits during two seaons in QPM (quality protein maize) hybrids. Association between grain yield and N uptake at anthesis, when found, was mainly explained by a close relationship between grain yield and above-ground biomass. No relationship was found between grain yield and N partitioning at anthesis. In both seasons grain yield was significantly positively associated with ear to above-ground biomass and ear to tassel weight ratios. The magnitude of the correlation between grain yield and senescence traits highly depended on climatic conditions.
KeywordsZea mays L. N deficiency N partitioning N uptake senescence QPM (quality protein maize)
Unable to display preview. Download preview PDF.
- Below F.E., Cazerta J.O., Seebauer J.R. 2000. Carbon/nitrogen interactions during ear and kernel development in maize. In: Westgate M.E and Boote K. (eds.), Physiology and modelling kernel set in maize. CSSA Special Publication 29, Madison, pp. 15–24.Google Scholar
- Dowswell C.R., Paliwal R.L., Cantrell R.P. 1996. Maize in the Third World, Boulder, Colorado, Westview Press.Google Scholar
- Machado A.T., Magalhães J.R. 1995. Melhoramento de milho para uso eficiente de N sob condições de estresse. In: Simpósio internacional sobre estresse ambiental: o milho en perspectiva, Sete Lagoas, Brasil. Embrapa-CNPMS, pp. 321–342.Google Scholar
- SAS Institute, 1987. SAS/STAT user’s guide, version 6. SAS Inst., Inc., Cary, NC.Google Scholar
- Srinivasan G., Cordova H., Vergara N., Rodríguez E., Urrea C. 2002. Potential of quality protein maize for promoting nutritional security in Asia. In: New directions for a diverse planet: Proceedings of the 4th Int. Crop Science Congress, Brisbane, Australia.Google Scholar