KWS (United Kingdom)

Abstract Multiple studies have identified genes affecting grain morphology, yet their capacity to deliver yield gains under field conditions remains unclear. We performed a multiyear, multilocation factorial evaluation of GRAIN WIDTH2 ( TaGW2 ) mutants in hexaploid wheat using BC 4 near-isogenic lines, sowing-density treatments and semi-dwarfing RHT1 backgrounds. Loss-of-function mutations in TaGW2 increased grain size and thousand grain weight (TGW) additively; with the aaBBDD single mutant showing the most stable singlelocus effect, while the aabbdd triple mutant achieved ~20% higher TGW across twelve field trials. However, overall grain yield remained unchanged or slightly reduced, reflecting a compensatory trade-off with grain number. Spike phenotyping of both main and secondary tillers showed comparable increases in TGW and spike yield despite fewer grains per spike, indicating that limited yield gain primarily reflects reduced spike number per unit area rather than decreased spike-level productivity. Effects were stable across sowing densities, whereas interactions with semi-dwarfing alleles were allele-specific: RHT-B1b partially suppressed TGW gains and accentuated yield penalties, whereas RHT-D1b maintained the large-grain phenotype and productivity. Across experiments, the TaGW2-A1D1 double mutant increased TGW (~14%) while maintaining yield stability, identifying it as a promising genotype for breeding. We conclude that TaGW2 is a reliable modifier of grain size but not yield in isolation.

Harnessing genetic diversity in major staple crops through the development of new breeding capabilities is essential to ensure food security1. Here we examined the genetic and phenotypic diversity of the A. E. Watkins landrace collection2 of bread wheat (Triticum aestivum), a major global cereal, by whole-genome re-sequencing of 827 Watkins landraces and 208 modern cultivars and in-depth field evaluation spanning a decade. We found that modern cultivars are derived from two of the seven ancestral groups of wheat and maintain very long-range haplotype integrity. The remaining five groups represent untapped genetic sources, providing access to landrace-specific alleles and haplotypes for breeding. Linkage disequilibrium-based haplotypes and association genetics analyses link Watkins genomes to the thousands of identified high-resolution quantitative trait loci and significant marker–trait associations. Using these structured germplasm, genotyping and informatics resources, we revealed many Watkins-unique beneficial haplotypes that can confer superior traits in modern wheat. Furthermore, we assessed the phenotypic effects of 44,338 Watkins-unique haplotypes, introgressed from 143 prioritized quantitative trait loci in the context of modern cultivars, bridging the gap between landrace diversity and current breeding. This study establishes a framework for systematically utilizing genetic diversity in crop improvement to achieve sustainable food security.

Wheat occupies a special role in global food security since, in addition to providing 20% of our carbohydrates and protein, almost 25% of the global production is traded internationally. The importance of wheat for food security was recognised by the Chief Agricultural Scientists of the G20 group of countries when they endorsed the establishment of the Wheat Initiative in 2011. The Wheat Initiative was tasked with supporting the wheat research community by facilitating collaboration, information and resource sharing and helping to build the capacity to address challenges facing production in an increasingly variable environment. Many countries invest in wheat research. Innovations in wheat breeding and agronomy have delivered enormous gains over the past few decades, with the average global yield increasing from just over 1 tonne per hectare in the early 1960s to around 3.5 tonnes in the past decade. These gains are threatened by climate change, the rapidly rising financial and environmental costs of fertilizer, and pesticides, combined with declines in water availability for irrigation in many regions. The international wheat research community has worked to identify major opportunities to help ensure that global wheat production can meet demand. The outcomes of these discussions are presented in this paper.

The pathogenicity and identity was studied of a field sample (PcE) of crown rust fungus Puccinia coronata collected in Hungary on wild couch grass (Elymus repens) and of a field sample (Psb) of stripe rust (P. striiformis) collected in the Netherlands on California brome (Bromus carinatus). We focused on the analysis of the host susceptibility of cultivated barley (Hordeum vulgare) to both pathogen samples, in direct comparison with an isolate of P. striiformis f.sp. tritici (Pst) and P. striiformis f.sp. hordei (Psh). At the seedling stage 83 % of the barley accessions were susceptible to PcE. At the adult plant stage, cultivated barley was predominantly resistant to this crown rust sample. Morphology, pathogenicity on Hordeum and Bromus and ITS DNA sequence analysis determined that PcE represents a European specimen of P. coronata f.sp. hordei. Sample Psb was pathogenic on 47 % of the cultivated barley at the seedling stage. This is intermediate between the isolates Psh (90 %) and Pst (10 %). Psb and Psh were pathogenic to grasses representing several genera. The host range of the Pst isolate was more narrow. We conclude that Psb is unlikely to represent a genotype of Psh that happened to have colonized B. carinatus, and is likely a distinct form of P. striiformis.

This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the effects of patient education compared with usual care on mortality and morbidity in patients with CHD.To explore the potential study level predictors of the effects of patient education in patients with CHD.