Authors:A. Rascio, E. Carlino, G. Santis, and N. Fonzo
This study is a multivariate discriminant analysis that was performed to identify a set of physiological characteristics that can be used to distinguish between groups of durum wheat genotypes differing for adaptation to semi-arid environments. To this aim, at first twenty-six genotypes were classified as “adapted”, “nonadapted” or “indeterminate” on the basis of yield and yield stability, as determined in a drought-prone environment of southern Italy, over a minimum of 4 and a maximum of 9 years. Subsequently fifteen morpho-physiological traits and the yields were assessed in a field study. Univariate statistical analysis of morpho-physiological traits to compare genotypes and groups of genotypes showed significant differences between the genotypes, although no single character could be used to discriminate between the genotype groups. On the contrary discriminant functions, based on 13 morpho-physiological traits, were effective for the full discrimination of all of the groups, with a 100% success rate. Four traits was the minimum needed to fully discriminate the “adapted” genotypes. Together with the water status parameter, the rheological properties and the affinity for bound water are new promising leaf traits, to distinguish between the plants coming from these different groups.
Authors:A. Rascio, E. Carlino, G. Nicastro, C. Platani, M. Russo, and N. Fonzo
A wheat (Triticum turgidum L. var. durum) mutant, designated k-plus, constitutively possesses high leaf potassium content and light-green leaves. To study the genetic basis of these traits and to find out their association, k-plus mutant was crossed to the wild type (WT) Trinakria, F1 and F2 populations were developed. The flag leaves of parental lines, F1 and F2 progeny were assayed for ion content, at the heading stage. Potassium content was greater in k-plus than in WT; the F1 hybrids behaved like to the WT, in both potassium and leaf colour. The number of genes conditioning leaf potassium content, was not more than one, as estimated by Castle-Wright method. A single recessive locus controls potassium content of k-plus mutant, with the wild type allele completely dominant over the new mutant. Broad sense heritability can be considered sufficient to obtain progress from selection, of k-plus phenotype. Light-green leaf colour was inherited as monogenic recessive allele, which co-segregate with the locus controlling potassium accumulation. Light-green F2 sub-population had, on the average, significantly more potassium content than green F2 sub-population. These preliminary results encourage further physiologic and genetic analysis of k-plus mutant.