Earliness is a critical agronomic trait that enables plants to avoid adverse weather conditions during the late growing season or at harvest. In wheat, earliness is controlled by at least three distinct mechanisms: vernalization requirement, photoperiod sensitivity, and a mechanism independent of the first two, so called, earliness per se. In this work we report a locus on chromosome 3B within NLP3-B1 (TraesCS3B02G190300) gene, coding a nitrate-sensitive transcription factor protein, which is associated with earliness in F_5:6 of PI-518620 x CI-17241 spring wheat cross. The variant ‘A’ of the single nucleotide polymorphism NLP3-B1: c.1824+137G>A, which is proper to evolutionary earlier haplotypes, provides heading and anthesis that is 2 days earlier. The effect of this novel marker on earliness was additive to the effect of PPD-D1 locus in the same population; however, the effect of the former was weaker. Similarly, allele Ppd-D1a and the variant ‘A’ of the NLP3-B1: c.1824+137G>A polymorphism statistically significantly reduced the plant height (for 2.2 and 1.3 cm, correspondingly) and changed some other agronomical traits; however, these light pleiotropic effects are not of practical value. The possible direct impact of NLP3-B1 on the timing of flowering via altered nitrate sensitivity has been discussed, and other candidate genes on chromosome 3B have also been suggested.

Отбор молекулярных маркеров для генетической паспортизации Triticum aestivum

The Ddw1 dwarfing gene is pivotal for reducing plant height and improving lodging resistance in triticale, but its pleiotropic effects on yield components and heading date pose significant challenges for breeders. This study identifies the Growth-Regulating Factor 9-6A (GRF9-6A) gene that compensates for these drawbacks. Field trials across locations (Moscow, Krasnodar) and years (2018, 2019) confirmed the effect of Ddw1, reducing plant height by 26.1–30.1 cm (31.8–32.5%) and thousand-kernel weight (TKW) by 6.0–6.3 g (11.8–15.7%) while increasing the harvest index by up to 4.8 percentage points in three out of four environments, with its effect nullified under the heat stress of Krasnodar 2019. In a Ddw1 background, the GRF9-6Ab allele distinguished by a 12 bp deletion in its promoter compensated for yield losses by increasing grain weight per main spike by up to 0.34 g (19.2%) via boosts in grain number per spike (up to 11.6%) and TKW (up to 11.5%). This combination also elevated the harvest index by up to 4.0 pp and, critically, provided a key agronomic advantage by accelerating heading by 6.3–6.5 days (10.0–10.2%), thereby mitigating the Ddw1-associated developmental delay. Our results demonstrate that pyramiding Ddw1 with the GRF9-6Ab allele the development of semi-dwarf, high-yielding, and early-maturing triticale cultivars for food and forage. This breeding strategy, facilitated by a newly developed diagnostic marker for GRF9-6Ab, is particularly advantageous for cultivation in environments similar to the Central Non-Chernozem region.

The Green Revolution dwarfing alleles Rht-B1b and Rht-D1b shorten the stem and reduce lodging, and under intensive management often raise yield, although this advantage may disappear in dry or low-input environments. Their frequency in spring bread wheat grown in Russia has not been established. We genotyped 370 accessions. None carried Rht-B1e or Rht-B1p, only eight carried Rht-B1b (2.2%) and one, Zolushka, carried Rht-D1b (0.3%); two were heterogeneous at Rht-B1. These figures describe this collection, not a probability sample of Russian spring bread wheat. Pedigrees trace the eight Rht-B1b carriers to five sources: three inherited the allele from a winter bread wheat parent, two from CIMMYT semi-dwarf material, and three belong to a single introduced lineage; none derives it from Russian spring wheat breeding. In 43 accessions grown in Moscow over three seasons, the three Rht-B1b carriers were 15.4% shorter than the 39 wild-type accessions (60.7 versus 71.8 cm, p = 0.021), whereas spike traits and grain yield in Moscow and Omsk did not differ significantly; with three carriers these comparisons are exploratory and small effects cannot be excluded. Because one field-evaluated carrier was as tall as the wild type, marker-based identification is needed wherever these alleles are deployed.

The rice gene QT12, which encodes the β subunit of the Sec61 translocon complex, has previously been shown to negatively regulate grain thermotolerance, suggesting that variation in related cereal genes may contribute to heat responses. We characterized the natural sequence diversity of three QT12 homeologs located on homoeologous group 3 chromosomes in bread wheat using publicly available whole-genome assemblies and Oxford Nanopore amplicon sequencing. TaQT12-A1 and TaQT12-D1 were highly conserved in their transcribed regions, whereas TaQT12-B1 was represented by two strongly differentiated haplotype groups, Hap1 and Hap2, distinguished by 108 sequence variants across the gene and its 7-kb flanking regions. The protein-coding sequence of TaQT12-B1 was conserved between the two haplotype groups, while most differences occurred in non-coding and flanking regions. A KASP marker was developed to distinguish the two groups and used to genotype 200 winter wheat accessions, of which six carried Hap2. Comparisons of grain-related traits over 2018–2020 revealed differences between haplotypes, but none remained significant after false discovery rate correction. Seasonal temperature records provided environmental context but did not support a clear haplotype-specific heat-response pattern. These results identify TaQT12-B1 as a candidate locus with substantial non-coding sequence variation and provide a molecular marker for further functional investigation of its haplotypes.