Authors:J. Díaz De León, R. Escoppinichi, N. Geraldo, A. Börner, and M. Röder
The parents (the landrace Chinese spring (CS) and a synthetic hexaploids (S6x)) and 17 derived single chromosome substitution lines (SL) were grown in parallel in the field under non-saline (1.0 dSm−1) and saline (12.0 dSm−1) conditions, and evaluated for a set of phenotypic traits. The performance of CS indicated it to have borderline salinity tolerance with respect to all of the traits except for leaf area (for which it behaved in as a salinity sensitive type). The SL 4D was early in booting, ear emergence, flowering and maturity, while 5D and 2B SLs were both late. The 2B SL produce 33% more ears than CS. The 5D SL under-performed with respect to ear weight, grain number per ear, grain weight per ear and 1000-grain weight both under non-saline and saline conditions. Under saline conditions, four SLs (1A>5A>1D>2B) outperformed Cs for ear length, and six SLs (1D>6A>4B>3A>3B>3D) showed an improved grain weight. The grains produce by the 2B SL were smaller than those of CS. Leaf area developed better in four SLs (4D>2B>1A>7D) than in CS.
Authors:S. Osipova, A. Permyakov, M. Permyakova, V. Davydov, T. Pshenichnikova, and A. Börner
Variation in tolerance of prolonged drought was identified among a set of single chromosome bread wheat substitution lines, involving the replacement of each cv. Chinese Spring chromosome in turn with its homologue from a synthetic hexaploid (Triticum dicoccoides × Aegilops tauschii). Water stress was applied under controlled conditions by limiting the supply of water to 30% from 100% aqueous soil. The reaction to the resulting long-term drought stress was quantified by three indices, based on grain yield components. Enhanced drought tolerance was associated with the presence of donor chromosomes 1A, 5A, 1D, 3D, 5D and 6D, and enhanced susceptibility with chromosomes 3A, 4B and 7D.
Authors:A. Vágújfalvi, V. Nagy, A. Soltész, and G. Galiba
Testing cereal frost tolerance goes back for decades in the Agricultural Research Institute, Martonvásár, Hungary. The climatic programmes used in the plant growth chamber have proved to be fairly efficient, but these methods are time-consuming and have become quite expensive in recent years. An attempt was made to shorten this process by reducing the cold hardening phase, and the freezing test has been simplified and shortened by measuring the relative conductance of leaf segments frozen in a liquid freezer. Frost-tolerant and sensitive wheat lines were tested, and the sensitivity of the system was checked by testing single chromosome substitution lines. Differences were found for all lines frozen at different temperatures. To reduce the costs of the experiment it was attempted to cold-harden the plants not only in a growth chamber but also in a cold room under very low light intensity and it was found that even under thess unfavourable conditions the plants developed a certain level of frost tolerance. The simplified frost tolerance test has proved to be effective, but requires further improvement due to the unsatisfactory significance levels.
Authors:A. Rojas, T. Castellanos, and J. Díaz De León
Wheat improves some traits when inoculated with Azospirillum. However, inconsistent results have been observed in field experiments. The ability of Azospirillum brasilense Cd to adhere to wheat was tested in a germplasm panel consisting of a number of bread wheat cultivars, synthetic hexaploids, synthetic derivatives, and a partial set of single chromosome substitution lines to determine the plant genetic role. Seeds of genotypes were grown in modified Hoagland's medium at seedling stage and then roots were inoculated with the bacteria and adhered cells were counted. The majority of the bread wheat cultivars and synthetic derivatives and some of the synthetic hexaploids were able to support bacterial adhesion. Neither the age of the seedling nor the imposition of either salinity stress or nitrogen starvation had any effect on the extent of adhesion. A pedigree analysis revealed that the root-adhered A. brasilense cultivars shared common ancestor(s), and the substitution line analysis suggested that the genes underlying the trait were located on chromosomes 5D and 6D. The present results are consistent with the notion that the D genome is the source of genetic variation for the capacity of A. brasilense to adhere to the seedling roots.