No abstract

The global and local climate changes determine the producing of highly-adaptive common (bread) wheat commercial cultivars of a new generation whose optimal earliness matches the climatic features of the territory where the cultivars are farmed. Principal component analysis involving our own and published data has been applied to investigate 98 commercial common wheat cultivars from Western and Eastern Siberia comparing their morphotypes; cultivar zoning time; length of the vegetation period; 1000-grain weight, and inheritance of spring growth habit. It demonstrated that the dominant Vrn gene polymorphism determining the spring growth habit of the Siberian cultivars was minimally polymorphic. In 75 % of the tested cultivars, the spring growth habit was controlled by digenic, namely dominant Vrn-A1 and Vrn-B1 genes. In 25 % of them (24 cultivars), spring growth habit is controlled by a single gene. In 19 and 5 of these cultivars spring growth habit is controlled by only one dominant gene, Vrn-B1 or Vrn-A1, respectively. In cv. Tulun 15, a trigenic control was identified. A conclusion about the optimality of the digenic control for the climatic conditions of both Western and Eastern Siberia has been confirmed. However, since none of the tested cultivars had the dominant Vrn-D1 gene typical of the regions of China and Central Asia bordering Siberia, it can be considered as an additional argument in favor of the European origin of Siberian common wheat cultivars. The revealed high frequency of the Vrn-B1c allele in the Western Siberian cultivars and the Vrn-B1a allele in the Eastern Siberian cultivars suggests their selectivity. The analysis also confirmed the dominance of red glume (ferrugineum, milturum) and awned spike (ferrugineum, erythrospermum) varieties in the Eastern Siberian cultivars, and white glume and awnedless spike (lutescens and albidum) ones in the Western Siberian cultivars. Small grain size cultivars are more typical of Eastern than Western Siberia. The retrospective analysis based on the cultivars' zoning time included in the "State Register for Selection Achievements Admitted for Usage" brought us to the conclusion that the earliness/lateness of modern Siberian commercial cultivars was not regionally but rather zonally-associated (taiga, subtaiga, forest-steppe and steppe zones).

Intraspecific classification of cultivated plants is necessary for the conservation of biological diversity, study of their origin and their phylogeny. The modern cultivated wheat species originated from three wild diploid ancestors as a result of several rounds of genome doubling and are represented by di-, tetra- and hexaploid species. The identification of wheat ploidy level is one of the main stages of their taxonomy. Such classification is possible based on visual analysis of the wheat spike traits. The aim of this study is to investigate the morphological characteristics of spikes for hexa- and tetraploid wheat species based on the method of high-performance phenotyping. Phenotyping of the quantitative characteristics of the spike of 17 wheat species (595 plants, 3348 images), including eight tetraploids (Triticum aethiopicum, T. dicoccoides, T. dicoccum, T. durum, T. militinae, T. polonicum, T. timopheevii, and T. turgidum) and nine hexaploids (T. compactum, T. aestivum, i:ANK-23 (near-isogenic line of T. aestivum cv. Novosibirskaya 67), T. antiquorum, T. spelta (including cv. Rother Sommer Kolben), T. petropavlovskyi, T. yunnanense, T. macha, T. sphaerococcum, and T. vavilovii), was performed. Wheat spike morphology was described on the basis of nine quantitative traits including shape, size and awns area of the spike. The traits were obtained as a result of image analysis using the WERecognizer program. A cluster analysis of plants according to the characteristics of the spike shape and comparison of their distributions in tetraploid and hexaploid species showed a higher variability of traits in hexaploid species compared to tetraploid ones. At the same time, the species themselves form two clusters in the visual characteristics of the spike. One type is predominantly hexaploid species (with the exception of one tetraploid, T. dicoccoides). The other group includes tetraploid ones (with the exception of three hexaploid ones, T. compactum, T. antiquorum, T. sphaerococcum, and i:ANK-23). Thus, it has been shown that the morphological characteristics of spikes for hexaploid and tetraploid wheat species, obtained on the basis of computer analysis of images, include differences, which are further used to develop methods for plant classifications by ploidy level and their species in an automatic mode.

VRNgenes, determining wheat sensitivity to vernalization, are the main genetic system that defnes the duration of the entire growing period and the durations of the main organogenesis phases. To date, several alleles have been described forVRN-1loci, and allele­specifc primers have been developed that allow rapid identifcation of allelic spectra in common wheat varieties and lines. The unequal influence of different alleles ofVRN-1loci on the duration of the growing period has also been shown; however, there is little information on the effect of the combination of different alleles on heading time. In developing genotypes having different alleles of dominantVRNgenes on the base of the same genetic background, it is necessary to study the genetic effects ofVRNgenes on the duration of the growing season and the individual developmental phases, as well as on productivity. Most varieties presently grown in Russia carry the dominant alleles of twoVRN-1genes:Vrn-A1aandVrn-B1aorVrn-B1c; thus, the task was to create lines combining the dominant alleles ofVrn-A1awithVrn-B1aandVrn-B1cagainst the genetic background of the winter variety Bezostaya 1 (Bez1Vrn-A1a/Vrn-B1aand Bez1Vrn-A1a/Vrn-B1c). Homozygous plants were isolated in the F2 generation by using known allele­specifc primers for theVrn-A1andVrn-B1loci. The durations of the tillering–frst node period, which is the key stage determining growing duration, and the period from shoots to heading were signifcantly reduced in lines with a combination of two dominant alleles ofVRN-1loci compared to isogenic lines of Bezostaya 1 with the dominant allelesVrn-B1aandVrn-B1c. The duration of these developmental phases also decreased in the obtained lines as compared to the isogenic line containing the dominantVrn-A1aallele, but the differences were not signifcant. No substantial differences were found in the duration of other growing phases in lines with two dominant alleles of theVRN-1loci as compared to isogenic lines of Bezostaya 1.