No abstract

Maize (Zea mays L.) bread is increasingly appreciated by consumers from the northwest of the Iberian Peninsula. However, the ancient maize varieties specifically selected for those uses have been replaced by hybrids with higher yield and lower flour quality. Besides, maize available comes from intensive agriculture, involving herbicides, insecticides and other potentially dangerous products. Organic production of traditional maize varieties for human consumption could be valuable for raising the returns of small local farmers in the northwest of Spain and the north of Portugal, and for matching the demands of consumers. Autochthonous varieties have been evaluated under organic farming and the quality of those with higher yield for bakery. Four autochthonous varieties were identified with the best performance under organic conditions and adequate quality for making bread and other traditional maize foods. Those varieties are "Tuy" (yellow kernel and medium growing cycle), "Sarreaus" (yellow kernel and early cycle), "Meiro" (black kernel and late cycle), and "Rebordanes" (white kernel and medium-early cycle). Traditional white, yellow and black maize varieties have been identified, and a selection program for increasing yield and quality is being performed for each.

Breeding maize (Zea mays L.) for traditional agriculture can increase quality and added value of agricultural products and allow the recovery of traditional foods. The objectives of this work were to evaluate improved open-pollinated populations under organic and conventional agriculture in order to determine the effects of selection for yield and flour yield and the relationship between agronomic and quality traits under both cropping systems. We have selected open-pollinated maize populations for flour yield and bakery quality under organic conditions, improved them under conventional conditions and evaluated the breeding programs under organic and conventional conditions. Breeding was efficient for grain and flour yield under organic agriculture for Meiro (an open-pollinated population with black grains) but not for the other populations neither in organic nor in conventional conditions. Yield ranks of varieties were moderately correlated under both conditions, and genotype  environment interaction (GE) was significant for most traits when the analyses of variance were made over all environments but also when organic and conventional environments were separated. GE was higher under organic agriculture.Correlations between traits were higher under conventional agriculture and there were important discrepancies between correlations in organic and conventional agriculture. We concluded that selection under conventional agriculture was efficient for one population under organic agriculture. Selection under the target environment could increase the possibilities of success.

Maize is traditionally used for bakery in several countries, and autochthonous varieties are increasingly demanded particularly for organic agriculture, but one of the dangers of cereal consumption is mycotoxin contamination. Mycotoxins are dangerous for health and might be present in any grain depending on genotypes and environments. In the present work we assess the natural levels of fumonisin and deoxynivalenol (DON) contaminations in nine diverse openpollinated maize varieties grown in four different locations, under organic or conventional conditions, in two regions from the humid Spain during two years. Differences were significant among locations and among varieties for fumonisin contamination but not for DON content.Locations were the main environmental source of variation affecting fumonisins while DON was more affected by years. The Basque locations had more fumonisin than the Galician locations, but there were no differences between organic and conventional environments.Fumonisin contamination was more variable than DON among locations and among varieties.Fumonisin and DON were highly correlated on average but correlations were low for each particular environment. Mean fumonisin and DON were below the threshold allowed by the EU, but the white-kernel medium late variety Rebordanes(P)C2 had more than 4.00 mg/kg of fumonisin in one location, while the early yellow variety Sarreaus had the lowest contamination. We conclude warning producers of the danger of natural contamination with mycotoxins for some varieties in specific environments.

Maize (Zea mays L.) used for human consumption is frequently processed following traditional methods with unknown effects. The objectives of this research consist of studying genotypic and environmental effects on grain quality for human consumption and evaluating traditional grain processing methods. Three maize varieties were evaluated for 2 yr in two locations. Populations were significantly different for grain quality while grain yield and pericarp damage were mostly affected by environment. Moisture content varied from 24% for early harvest to 20% for late harvest, pericarp damage from 24 to 19%, and germination from 62 to 84%. Environments explained most of the variation while harvest dates affected mainly grain hardness and germination. In addition, white flint maize grains were processed with a combination of drying, freezing, vacuum, and storage treatments. Drying with warm air after natural drying increased grain quality compared to natural drying alone. Medium term storage increased grain quality but reduced germination. Traditional processing was adequate for adapted varieties and typical uses but additional drying, freezing, or vacuum can be worthwhile depending on grain conditions and final use. To optimize quality, the key issues are appropriate growth cycle and proper harvest time. Furthermore, quality and agronomic performance can be managed independently of each other except for the negative correlation between moisture and milling test.