Phenotypic effects of the dwarfing gene Rht-17 in spring durum wheat under two climatic conditions

Alleles of the genes, conferring a dwarfing phenotype, play a crucial role in wheat breeding, as they not only reduce plant height, ensuring their resistance to lodging, but also have a number of positive and negative pleiotropic effects on plant productivity. Durum wheat carries only two subgenomes (A and B), which limits the use of the D-subgenome genes and requires the expansion of the arsenal of dwarfing alleles and the study of their effects on height and agronomically important traits. We studied the effect of the gibberellin-insensitive allele Rht-B1p in the B2F2:3 families, developed by crossing Chris Mutant /#517//LD222 in a field experiment in Moscow and Krasnodar. In our experiments, plants homozygous for Rht-B1p were shorter than those homozygous for the wild-type allele Rht-B1a by 36.3 cm (40 %) in Moscow and 49.5 cm (48 %) in Krasnodar. In the field experiment in Krasnodar, each plant with Rht-B1p had one less internode than any plant with Rht-B1a, which additionally contributed to the decrease in plant height. Grain weight per main spike was lower in plants with Rht-B1p than in plants with Rht-B1a by 12 % in Moscow and by 23 % in Krasnodar due to a decrease in 1000 grain weight in both regions of the field experiment. The number of grains per main spike in plants with Rht-B1p was higher in comparison to that with Rht-B1a by 6.5 % in Moscow due to an increase in spikelet number per main spike and by 11 % in Krasnodar due to an increase in grain number per spikelet. The onset of heading in plants with Rht-B1p in comparison with the plants with the wild-type allele Rht-B1a was 7 days later in Krasnodar. The possibility and prospects for the use of Rht-B1p in the breeding of durum wheat are discussed

Allele mining of TaGRF-2D gene 5'-UTR in Triticum aestivum and Aegilops tauschii genotypes.

The low diversity of the D-subgenome of bread wheat requires the involvement of new alleles for breeding. In grasses, the allelic state of Growth Regulating Factor (GRF) gene is correlated with nitrogen uptake. In this study, we characterized the sequence of TaGRF-2D and assessed its diversity in bread wheat and goatgrass Aegilops tauschii (genome DD). In silico analysis was performed for reference sequence searching, primer pairs design and sequence assembly. The gene sequence was obtained using Illumina and Sanger sequencing. The complete sequences of TaGRF-2D were obtained for 18 varieties of wheat. The polymorphism in the presence/absence of two GCAGCC repeats in 5' UTR was revealed and the GRF-2D-SSR marker was developed. Our results showed that the alleles 5' UTR-250 and 5' UTR-238 were present in wheat varieties, 5' UTR-250 was presented in the majority of wheat varieties. In Ae. tauschii ssp. strangulata (likely donor of the D-subgenome of polyploid wheat), most accessions carried the 5' UTR-250 allele, whilst most Ae. tauschii ssp. tauschii have 5' UTR-244. The developed GRF-2D-SSR marker can be used to study the genetic diversity of wheat and Ae. tauschii

Pre-harvest sprouting resistance and haplotype variation of ThVp-1 gene in the collection of wheat-wheatgrass hybrids.

The germplasm collection of 87 wheat-wheatgrass hybrids developed in Tsitisin Main Botanical Garden (Russia, Moscow) was evaluated for resistance to pre-harvest sprouting (PHS) by spike sprouting (SS) and germination index (GI) assays as well as for spike and grain features. The PHS resistance variation and haplotype polymorphism of the wheatgrass ThVp-1 and wheat TaVp-1B genes orthologues of Vp-1 was revealed in the studied collection. Four haplotypes of ThVp-1 were revealed: ThVp-1a (41% of the entries), ThVp-1b (13%), ThVp-1c (29%), and ThVp-1d (15%). The association between the allelic state of ThVp-1 and PHS resistance in the wheat-wheatgrass hybrids was shown: haplotype ThVp-1d of the wheatgrass Vp-1 gene is significantly associated with reduced PHS in the wheat-wheatgrass hybrids (mean SS 0.33, mean GI 0.64). The resistant entries may be perspective as a source of PHS resistance in the development of commercial cultivars of perennial wheat

Association between <i>ThVp-1</i> haplotypes and SS values in the wheat-wheatgrass hybrid collection.

<p>Association between <i>ThVp-1</i> haplotypes and SS values in the wheat-wheatgrass hybrid collection.</p

Estimation of the PHS resistance by spike sprouting assay.

<p>1–1451; 2–150-k; 3–1626; 4–4044.</p

The combined results of application of the Vp1BB4_<i>Hae</i>III and Vivip markers in the wheat-wheatgrass hybrids.

<p>The combined results of application of the Vp1BB4_<i>Hae</i>III and Vivip markers in the wheat-wheatgrass hybrids.</p

Electrophoresis of the CAPS-marker Vp1BB4_<i>Hae</i>III fragments.

<p>The ~600 bp (arrow) and ~550 bp (*) are diagnostic fragments for the wheatgrass <i>ThVp1</i> gene. M—size standard (100 bp DNA Ladder), 1 –<i>Triticum aestivum cv</i>. <i>Nota</i>, 2–90, 3–150 k., 4–168, 5 –<i>Th</i>. <i>intermedium</i> PI 401200.</p

Classification of entries based on the results of germination index (GI) and spike sprouting (SS) assays.

<p>Classification of entries based on the results of germination index (GI) and spike sprouting (SS) assays.</p

Association between <i>ThVp-1</i> haplotypes and GI values in the wheat-wheatgrass hybrid collection.

<p>Association between <i>ThVp-1</i> haplotypes and GI values in the wheat-wheatgrass hybrid collection.</p

Association between <i>TaVp-1B</i> alleles (of wheat origin) and GI values in the wheat-wheatgrass hybrid collection.

<p>Association between <i>TaVp-1B</i> alleles (of wheat origin) and GI values in the wheat-wheatgrass hybrid collection.</p