Authors:C. Riefolo, D. Ficco, L. Cattivelli, and P. Vita
The genetic variations of high and low molecular weight glutenin subunits (HMW-GS and LMW-GS) as well as of ω- and γ-gliadins in 562 accessions of 7 tetraploid Triticum turgidum L. subspecies were investigated using sodium dodecyl sulfate polyacrylamide-gel electrophoresis (SDS-PAGE). A total of 26 HMW-GS alleles (7 at Glu-A1 and 19 at Glu-B1 loci) with 63 allelic combinations, as well as 11 LMW-GS alleles (5 at Glu-A3, 4 at Glu-B3 and 2 at Glu-B2 loci) with 26 allelic combinations, were detected. Two novel HMW-GS, called B1cf and B1cg, were discovered in T. dicoccum, B1cg was also found in T. turanicum. The Glu-B1 locus showed the highest values of genetic diversity index (H), with a mean of 0.72. As regards gliadins, 8 alleles at Gli-B1 locus have been found. The dendrogram based on allelic frequencies, revealed that T. durum, T. carthlicum and T. polonicum grouped a part from the other subspecies. This behaviour suggested probably different evolutive pathways among the tetraploid wheats.
Authors:G. Borrelli, D. Ficco, L. Giuzio, M. Pompa, L. Cattivelli, and Z. Flagella
Durum wheat (Triticum turgidum L. Desf.) is a species well adapted to the Mediterranean environments where salt stress due to seawater intrusion is an increasing problem. The purpose of this study was to deep insight into the relationships among physiological, productive and qualitative aspects under salinity, being these aspects still poorly investigated in durum wheat. In 2004–2005 crop season 10 durum wheat genotypes of different origin and breeding time were grown in a naturally-lit polycarbonate greenhouse under three irrigation water salinity levels (0.9, 6.0 and 12.0 dS m−1). A complete randomized block design with three replications was adopted. The osmotic damage was evaluated by estimating relative water content (RWC), leaf water potential (Φw) and osmotic potential at full turgor (Φπ100). The toxic damage to the plants was evaluated by measuring Na+ accumulation and Na+/K+ ratio in the leaves. Differences in yield performance were evaluated by assessing the main yield components and some qualitative traits, carotenoid pigment and protein content and Sedimentation test in sodium dodecyl sulphate. A significant effect of genotype, salt stress and of their interaction on all the characters was observed. Durum wheat genotypes generally showed a moderate tolerance to salt stress. The genotype performance was dependent on stress level and RWC maintenance. Osmotic adjustment and low sodium accumulation were found to play a key role in salt tolerance. An improvement in the grain quality characters on increasing salinity level, consistently with a yield decrease, was observed.