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A set of 20 accessions of durum wheat (Trilicum lurgidum L., durutn group), which mostly included exotic landraces from various Mediterranean countries, and four Italian improved varieties were evaluated for grain yield in five environments and for quality traits in two environments of Sicily. Glutenin composition was also assessed electrophoretically on six seeds per entry. The cultivars differed (P ^ 0.01) for yield, protein content and sodium dodecyl sulphate (SDS-sed) sedimentation volume, in the presence of significant (P < 0.001) genotypeenvironment interaction effects. These effects were large for yield and moderately large for protein content relative to genotype main effects following estimation of variance components. Most exotic cultivars yielded comparably with, and some of them showed greater stability than, the best yielding Italian variety 'Simeto'. Some exotic cultivars combined outstanding yield, protein content and SDS-sedimentation values and represent therefore extremely valuable germpiasm sources to broaden the local genetic base. The glutenin composition LMW-2 and HMW 7 -F 8 was positively associated with gluten quality. Six entries showed heterogeneous electrophoretic patterns, suggesting the presence ofdifferent genotypes within the cultivar.

Large‐scale trait evaluation may enhance the utilization of germplasm collections by breeders. However, there is concern that this information may not be repeatable outside the area of testing because of large genotype × location interaction. Our objective was to assess the repeatability of large‐scale evaluation results for durum wheat [Triticum turgidum (L.) Thell. ssp. turgidum conv. durum (Desf.) MacKey] across two areas of the Mediterranean region. A subset of 600 entries from a world collection was evaluated for six agronomic traits at one site in northern Syria and one in Sicily. Pearson's and Spearman's rank correlations of entry values between locations indicated that the repeatability as measured by both coefficients was high for heading time (r ≥ 0.73), moderately high for kernel weight and plant height (0.48 ≤ r ≤ 0.57), relatively low for grain yield and kernels per spike (0.18 ≤ r ≤ 0.30), and non‐significant for early vigor score. Comparison between phenotypic and genetic correlations suggested that not only genotype × location interactions but also experimental errors contributed substantially to departures from complete repeatability. When each location alternated as the selection site and the other as the test site, at least 50% of the advantage shown by the top 10% entries over the remaining accessions at the selection site could be maintained at the test location for early or late heading, high kernel weight, and short or tall stature, for which 30 to 57% of selected entries were common to both sites. At least 20% of the selection advantage was maintained for high kernels per spike and grain yield. The results support the potential usefulness of large‐scale germplasm evaluation trials for crop improvement.

. 2004. Effect of durum wheat (Triticum turgidum L. var. durum) semolina extraction rate on semolina refinement, strength indicators and pasta properties. Can. J. Plant Sci. 84: 1001-1013. Since the 1980s, there have been general trends in the durum wheat milling industry to higher semolina extraction rate, and in the pasta processing industry to the use of higher drying temperatures. During this time, specification of gluten strength by gluten index, mixograph mixing properties and alveograph parameters has also become widespread. These trends prompted this study of the appropriateness of protocols for quality testing of Canadian durum wheat breeding lines. Four cultivars with intrinsic differences in yellow pigment levels and gluten strength were grown in field plots in Swift Current, Saskatchewan for three consecutive years. A laboratory-scale milling procedure was modified to produce semolina at extraction rates from about 65% to about 80%. Milling to extraction rates above 65%, the extraction rate used routinely in quality testing of Canadian durum wheat breeding lines, had a major impact on semolina ash content and colour, but did not offer any advantage in ranking cultivars for either semolina yield or semolina refinement. Gluten strength, as measured by gluten index, was independent of semolina extraction rate. Dough strength, as measured by mixograph properties and alveograph properties, showed a tendency to weakening at high extraction, particularly for strong cultivars. Semolina was processed into spaghetti using low-temperature (LT), high-temperature (HT) and ultra-high-temperature (UHT) drying cycles. The firmness of cooked spaghetti was predominantly influenced by protein content. As a result, cultivars generally ranked in spaghetti firmness according to protein content. Regardless of drying cycle or cultivar, spaghetti firmness increased as drying temperature increased. Spaghetti dried at LT was less yellow than spaghetti dried at HT or UHT, probably due to thermal inactivation of the bleaching enzyme lipoxygenase at HT and UHT. Regardless of drying cycle, spaghetti became duller, more red and less yellow as extraction rate increased. For each spaghetti trait, cultivar ranking remained relatively constant regardless of extraction rate or drying temperature. On the basis of these results, there appears to be no advantage to increasing semolina extraction rate beyond 65% for evaluation of durum wheat milling performance, gluten strength or pasta properties. In addition, it appears that one drying cycle is adequate to reliably evaluate durum wheat lines for spaghetti colour and firmness. Depuis les années 80, la tendance générale dans l'industrie meunière consiste à extraire de plus en plus de semoule du blé dur alors que l'industrie des pâtes alimentaires recourt à des températures de séchage de plus en plus élevées. Durant le même laps de temps, la détermination de la fermeté du gluten d'après l'indice de gluten, les propriétés de pétrissage révélées au mixographe et les paramètres de l'alvéographe...

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