There is still disagreement among scientists on the exact origin of common wheat (Triticum aestivum ssp. aestivum), one of the most important crops in the world. The first step in the development of the hexaploid aestivum group (ABD) may have been hybridisation between T. urartu (A), as pollinator, and a species related to the Sitopsis section of the Aegilops genus (S) as cytoplasm donor, leading to the creation of the tetraploid species T. turgidum ssp. dicoccoides (AB). The following step may have involved hybridisation between T. turgidum ssp. dicoccon (AB genome, cytoplasm donor), a descendant of T. turgidum ssp. dicoccoides, and Ae. tauschii (D genome, pollinator), resulting in the hexaploid species T. aestivum ssp. spelta (ABD) or some other hulled type. This form may have given rise to naked types, including T. aestivum ssp. aestivum (ABD). The ancestors of the tetraploid T. timopheevii (AG) may have been the diploid T. urartu (A genome, pollinator) and Ae. speltoides (S genome, cytoplasm donor). Species in the timopheevii group developed later than those in the turgidum group, as confirmed by the fact that the G genome is practically identical to the S genome of Ae. speltoides, while the more ancient B genome has undergone divergent evolution. Hybridisation between T. timopheevii (AG, cytoplasm donor) and T. monococcum (A m, pollinator) may have resulted in the species T. zhukovskyi (AGA m). Research into the relationships between the various species is of assistance in compiling the taxonomy of wheat and in avoiding misunderstandings arising from the fact that some species are known by two or more synonymous names.
On areas used for agriculture copper toxicity is one of the most important forms of heavy metal pollution, especially where field crops are to be grown in fields previously used as orchards or vineyards, treated for a long period with pesticides containing copper. Only varieties with good tolerance of soil with a high copper content should be grown on such areas. The selection of copper-tolerant varieties is complicated, however, by the fact that it is difficult to study copper tolerance under field conditions. Heavy metal tolerance is generally tested in hydroponic cultures, in which interfering factors can be minimised, but it is impossible to test a large number of genotypes or segregating generations using this method. Another problem in such experiments is that the conditions existing in hydroponic cultures bear little resemblance to those found in the field, so little information is obtained on the real adaptation of the varieties. The aim of the present experiments was thus to elaborate a soil-based technique suitable for determining the copper tolerance of various genotypes and allowing the simultaneous testing of a large number of genotypes under conditions approaching those found in the field. The results indicate that the copper tolerance of seedlings can be determined by growing them to an age of 2 weeks in soil containing 1000-1500 mg/kg CuSO4 × 5 H2O, since genetic differences in copper tolerance could be clearly distinguished under these conditions. The copper tolerance of plants grown in copper-containing soil exhibited a close correlation with the results obtained in physiological tests in hydroponic culture.
The growing interest in emmer cultivation has no doubt been stimulated by the increasing demand for traditional foods with an image of naturalness, especially on the organic market. The new economic situation could stimulate the breeding and production of emmer as the source of an especially valuable foodstuff. It is the task of breeders to produce emmer varieties that can survive even the hardest winter occurring in the targeted cultivation area without serious damage. The best sources to improve the winter hardiness are probably the emmer genetic resources stored in genebanks. Unfortunately no public data are available on the frost tolerance and winter hardiness of the various genebank accessions. In the present research the frost tolerance and winter hardiness of 10 winter emmer genebank accessions were studied under nursery and phytotronic conditions. The results suggest that the majority of the populations studied are frost-sensitive, and only few landraces have an acceptable level of winter hardiness and frost resistance.
Authors:F. Szira, I. Monostori, G. Galiba, M. Rakszegi, and A.F. Bálint
Wheat-based food has great importance in human nutrition: in European countries they provide 20–30% of the daily calorie intake, and additionally, the wholemeal and healthy food becomes even more popular. Mineral content in grains is dependent on genetic and environmental factors (varieties, soil type, geographical location of the growing area, etc.), therefore, it is complicated to estimate how many percentage of the daily micronutrient requirements can be covered by wheat-based products. In this study, copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se) and zinc (Zn) contents of 13 commercial wheat flour products, and the white flour and wholemeal of 24 winter type bread wheat varieties were studied to estimate the nutritional value of these products. All investigated samples were produced in Hungary. Significant variation was revealed in the case of all mineral elements in the different brands of wheat flours. Generally, the white flour enriched with germ showed higher mineral contents than the average values of normal white flours. Furthermore, the wholemeal has higher Cu, Fe, Mn and Zn, but not higher Se contents than the white flours. Mo content was also higher in some brands of white flour than in wholemeal.The investigated winter wheat varieties showed significant differences in the case of Fe, Mn, Se and Zn contents, but none of the varieties showed outstandingly high micronutrient content. The milling process — as it was expected — reduces the concentrations of four elements (Fe 33%; Mn 88%; Zn 71%; Cu 44%); however, the Se and Mo concentrations were not affected significantly. Using the average micronutrient content in the wholemeal of varieties, the daily Mn and Fe requirement can be covered by the consumption of about 250 g wholemeal. Additionally, the daily Mo requirement could be met by the daily consumption of 140–190 g of commercial white or wholemeal flour.
Authors:A. F. Bálint, G. Kovács, A. Börner, G. Galiba, and J. Sutka
The relatively copper-tolerant wheat variety Chinese Spring (recipient), the copper-sensitive variety Cappelle Desprez (donor) and their substitution lines were screened for copper tolerance in a soil pot experiment under artificial growth conditions. Chromosomes 5A, 5B, 5D and 7D of Cappelle Desprez significantly decreased the copper tolerance of the recipient variety to varying extents. By contrast, the 6B and 3D chromosomes significantly increased the copper tolerance of Chinese Spring, suggesting that a wide range of allelic differences could be expected between wheat genotypes for this character. The significant role of homologous group 5 in copper tolerance was confirmed by testing wheat-rye substitution lines. The substitution of rye chromosome 5R (5R/5A substitution line) into a wheat genetic background significantly increased the copper tolerance of the recipient wheat genotype. The results suggest that chromosomes 5R and 5A probably carry major genes or gene complexes responsible for copper tolerance, and that the copper tolerance of wheat can be improved through the substitution of a single chromosome carrying the responsible genes. At the same time, it is also possible that the effect of homologous group 5 is not specific to copper tolerance, but that the genes located on these chromosomes belong to a general stress adaptation (frost, cold, vernalisation requirements, etc.) complex, which has already been detected on this chromosome. To answer this question further studies are needed to determine the real effect of these chromosome regions and loci on copper tolerance.
Authors:F. Tóth, Franciska Tóthné Bogdányi, Renáta Petrikovszki, Anita Gódor, M. Zalai, B. Bálint, P. Sunder, and A. Myrta
The effectiveness of dimethyl disulfide (DMDS) to control root-knot nematodes (Meloidogyne spp.) and weeds was tested for the first time in Hungary in two consecutive protected cucumber crops with application made only before the first crop. The treatments were Accolade EC (DMDS 94.1%) at 400 l/ha applied by driplines, Nemathorin 10 G (fosthiazate) at 30 kg/ha, and an untreated control. During the first cucumber cycle vigour-index, yield, root-gall index, Meloidogyne juveniles in the soil and germination of weeds were evaluated. All considered parameters were significantly improved by using DMDS compared respectively to the chemical standard and untreated control: (i) vigour-index of 7.0, 4.3 and 3.6; (ii) cumulative yield/sample of 45.1 kg, 30.9 kg, and 16.6 kg; root-gall index (RGI) of 1.2, 4.9, and 5.9; (iii) M. incognita J2/25 g soil of 0.25, 48.5 and 78.0, and (iv) number of weed seedlings/sample in the 20–30 cm soil profile of 1.1, 2.6, and 4.2. During the second cucumber crop, only root-gall index was evaluated. Results showed that a single DMDS treatment applied before the first crop had a prolonged beneficial effect on the following crop. In the second crop cycle, root gall indices were 5.58, 9.18, and 8.44 for DMDS treated plots, chemical control and untreated control, respectively.