Influence of genotype and environment on bread wheat triticum aestivum as evaluated in tests of baking quality
Rousset, M.; Triboi, E.; Branlard, G.; Godon, B.
Agronomie 5(7): 653-664
ISSN/ISBN: 0249-5627 Accession: 005685241
The purpose of the experiments described in this paper was to understand the nature of the relationships observed between different tests of baking quality and then to obtain a better understanding of the influence of the characteristics of the samples under study on the level of correlation observed between the tests. The following tests were compared in our experiments: crude protein content, Pelshenke test, Zeleny sedimentation value, SDS sedimentation value, Chopin alveograph, percentage hydration with Brabender farinograph, Hagberg falling number, CNERNA breadmaking assay, micro cooking tests of Godon and Bourdet. The samples studied came from two main experiments: 1) 2 cultivars grown in one year at one location under 16 growing conditions differing qualitatively and quantitatively in nitrogen nutrition. Under such conditions one observed fairly high variation in yield and in baking quality for the same genotype (environmental variation); 2) study of a series of genotypes highly diversified for their baking quality, grown in a multilocation trial. The variations observed in the harvested samples were due partly to genetic variation and partly to environmental variation. Phenotypic correlation coefficients were calculated within each location and for all the locations (between-cultivar means calculated over all locations). Depending on the origin of the variation (genotypic or environmental) the relationships observed between quality tests were completely different. In the 'agronomy trial', the environmental variation in the tests for a given genotype was very often in direct relation with the quantitative variation in proteins. However, depending on the test considered, the pattern of variation in relation to protein content could be very different. In contrast, in the interstation trial, we had to deal mainly with genotypic variation within each location, variation in the quality tests was more related to qualitative variation in proteins (relative proportions of the protein fractions). From these results, the authors propose that great care should be taken in choosing and describing the samples analyzed in studies on new technological tests and on the biochemical basis of the baking quality of wheat grain.