Abstract
Maize (Zea mays L.) landraces are an important source of genes for improving commercial germplasm. Today, drought tolerance and grain quality are major challenges in maize cultivation due to climatic changes and population growth. The Maize Research Institute genebank has a drought tolerant collection, which includes 13 landraces (from the former Yugoslavia) and 12 introduced populations (from different countries). These accessions were analyzed for protein, oil, starch and tryptophan contents, in order to identify drought tolerant accessions with high grain quality. Also, simple sequence repeat (SSR) analysis with specific primers for opaque2 recessive allele (o2) was carried out. All analyzed accessions showed high levels of protein. Oil content ranged from 3.75 % to 5.40 % and starch content from 67.5 % to 71.30 %. Average protein content was not different (p < 0.01) between landraces and introduced populations. Starch and oil contents were higher in introduced populations at 0.84 % and 0.39 %, respectively (p < 0.01). Twenty-three accessions had high levels of tryptophan content. A high percentage of kernel type 1 and 2 indicated the presence of endosperm hardness modifier genes. Recessive o2 allele was found in most of the accessions. Absence of o2 in some high tryptophan accessions indicated action of another mutation. In two high tryptophan accessions an unknown band was detected. Absence of negative correlations between proteins, tryptophan and oil makes certain accessions suitable for use in the simultaneous improvement of target genotypes for these traits. Identified drought tolerant, high quality accessions can be used in breeding programs aimed at nutritional improvement of maize grown under drought conditions.
Highlights
It has been predicted that by 2020 the demand for maize (Zea mays L.) in developing countries will overtake the demand for both wheat and rice - by 2025 maize is likely to become the crop with the greatest production globally (Rosegrant et al, 2008).Maize cultivation has been primarily aimed at increasing yield potential and stability under different environmental conditions
The Maize Research Institute genebank has a drought tolerant collection, which includes 13 landraces and 12 introduced populations. These accessions were analyzed for protein, oil, starch and tryptophan contents, in order to identify drought tolerant accessions with high grain quality
Quality protein maize (QPM) has increased amounts of essential amino acids lysine and tryptophan, and increases the nutritional value for protein-deficient populations (Krivanek et al, 2007), while in animal feed significantly increases the rate of pig weight gain (Sofi et al, 2009)
Summary
It has been predicted that by 2020 the demand for maize (Zea mays L.) in developing countries will overtake the demand for both wheat and rice - by 2025 maize is likely to become the crop with the greatest production globally (Rosegrant et al, 2008).Maize cultivation has been primarily aimed at increasing yield potential and stability under different environmental conditions. The quality of maize kernel composition is extremely important for human and animal nutrition and chemical characterization of the grain should become an inevitable component of maize cultivation programs. The relative chemical composition (e.g. protein, oil, and starch contents) in grains defines the purpose for which maize will be used (White et al, 2001; Baye et al, 2006). Redesigning maize for improved kernel qualities may require introduction of novel alleles not presently found in commercial maize germplasm. Teosinte and landraces harbor phenotypic variation that can facilitate genetic dissection of kernel traits and grain quality, leading to improvement via traditional plant cultivation and/or genetic engineering (Flint-Garcia et al, 2009). Using teosinte and landrace accessions as sources of genetic variation for maize breeding is especially significant for genes that have limited or no variation remaining in modern inbreds (Wright et al, 2005; Yamasaki et al, 2005)
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