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Soil salinity results in reduced productivity in field peas, making soil salinity tolerance a critical breeding objective. In this study, four pot experiments were carried out in semi-controlled environments over four consecutive years to assess the contribution of seedling vigour to salinity tolerance at the seedling stage. Split-plot designs were used to assess the effect of salt stress (sodium chloride solution at 16 dSm−1) and control conditions. Extensive sets of advanced breeding lines were used in 2018–2020 to assess growth differences in relation to the treatment, with elemental analysis used on a subset of 15 lines in 2021. A salt tolerance index (STI) was defined as a proportion of shoot biomass under salt stress (DWstress) relative to the shoot dry weight under control (DWctrl). Visual scores of salt stress were recorded on a 1–10 scale (1 = tolerant, 10 = susceptible) from salt stress treatments. The consistent positive and significant correlations (p < 0.01) between shoot DWctrl and DWstress indicated that vigorous genotypes maintained higher shoot DWstress. Both the shoot DWctrl and shoot DWstress had negative and significant (p < 0.01) correlations with visual scores of salt stress. Shoot DWstress showed strong positive correlations with STI (p < 0.01). Both the shoot DWctrl and Shoot DWstress had negative correlations (p < 0.01) with shoot Na+ whereas shoot DWstress had a positive correlation (p < 0.05) with root Na+ concentration. The results indicated that seedling vigour (measured as shoot DWctrl) contributed to salinity tolerance by maintaining improved shoot DWstress, limiting Na+ deposition in shoot and enduring less tissue damage in field pea seedlings. Additional field evaluations are required to establish the correlations of tolerance at seedling stage with yield under saline conditions. The insights obtained from this study may assist field pea breeders in identifying salt-tolerant parent plants, offspring, and breeding lines during the initial growth phases. [ABSTRACT FROM AUTHOR]

The objective of this research was to characterize the high level of resistance to stripe that has been observed in the released wheat cultivar, Chuanmai45. A combination of classic genetic analysis, molecular and cytogenetic methods were used to characterize resistance in an F2 population derived from Chuanmai45 and the susceptible Chuanmai42. Inheritance of resistance was shown to be conferred by two genes in Chuanmai45. Fluorescence in situ hybridization (FISH) was used along with segregation studies to show that one gene was located on a 1RS.1BL translocation. Molecular markers were employed to show that the other locus was located on chromosome 4B. The defeated gene, Yr24/26, on chromosome 1BL was present in the susceptible parent and lines that recombined this gene with the 1RS.1BL translocation were identified. The germplasm, loci, and associated markers identified in this study will be useful for application in breeding programs utilizing marker-assisted selection. [ABSTRACT FROM AUTHOR]

The slow-rusting and mildewing gene Yr18/Lr34/Pm38/Sr57 confers partial, durable resistance to multiple fungal pathogens and has its origins in China. A number of diagnostic markers were developed for this gene based on the gene sequence, but these markers do not always predict the presence of the resistant phenotype as some wheat varieties with the gene are susceptible to stripe rust in China. We hypothesized that these varieties have a suppressor of Yr18. This study was undertaken to determine the presence of Yr18, the suppressor and/or another resistance gene in 144 Chinese wheat landraces using molecular markers and stripe rust field data. Forty-three landraces were predicted to have Yr18 based on the presence of the markers, but had final disease severities higher than 70%, indicating that this gene may be under the influence of a suppressor. Four of these landraces, 'Sichuanyonggang 2', 'Baikemai', 'Youmai' and 'Zhangsihuang', were chosen for genetic studies. Crosses were made between the lines and 'Avocet S', with further crosses of Sichuanyonggang 2 × 'Huixianhong' and Sichuanyonggang 2 × 'Chinese Spring'. The F1 plants of Sichuanyonggang 2/Chinese Spring was susceptible indicating the presence of a dominant suppressor gene. The results of genetic analyses of F2:3 and BC1F2 families derived from these crosses indicated the presence of Yr18, a Yr18 suppressor and another additive resistance gene. The Yr18 region in Sichuanyonggang 2 was sequenced to ensure that it contained the functional allele. This is the first report of a suppressor of Yr18/Lr34/Pm38/Sr57 gene with respect to stripe rust response. [ABSTRACT FROM AUTHOR]

Synthetic hexaploid wheat (SHW) is a valuable source of genetic diversity for germplasm enrichment in wheat breeding. In China, SHWderived material has shown significant yield increases. A 3-yr field experiment at Guanghan and Jiangyou in the Sichuan Basin of China was conducted to characterize the potential of three SHW-derived cultivars (SDCs) with five local elite nonsynthetic-derived cultivars as checks (NSCs). On average, SDCs showed an 11.5% or 951 kg ha-1 yield increase compared with NSCs. This yield gain was mainly attributed to increases in both grain number m-2 (5.7%) and thousand kernel weight (5.9%). A higher rate of aboveground dry matter accumulation, especially in the early growth stages, was observed in the SDCs. The SDCs also had better partitioning to the grain, as evidenced through an increased harvest index (HI). The SDCs had a relatively compact and erect plant type with medium and upper leaves having a mean extinction coefficient at 45° (EC45°) increase of 8.4% above the NSCs at 20-d after flowering. Correlations between grain yield components and physiological traits were analyzed. We concluded that the use of SHW has the potential to significantly increase wheat yield grown under rain-fed environments with low photosynthetically active radiation. [ABSTRACT FROM AUTHOR]

Future productivity increases of lentil in the face of changing climates and their expansion into areas traditionally considered marginal for commercial production will require greater tolerance to a range of abiotic constraints, particularly in relation to edaphic conditions. Variation in root system architecture presents a possible means of addressing these constraints. Whilst considerable attention has been paid in the past to above-ground traits; little attention has been given to how root traits can improve adaptation to new environments and productivity. This study aimed to characterise the diversity in root traits present in the Australian lentil germplasm and how breeding may have impacted these traits. The study examined 36 genotypes of lentil registered over the past 27 years in Australia. The experiments were carried out under glasshouse conditions in 2021 and in the field in 2020 and 2021. Results showed a significant variation in both shoot and root traits. Late maturing genotypes accumulated more root biomass, which was associated with a negative impact on yield, harvest index and 100 grain weight. Root traits that varied substantially among genotypes included root biomass, length, depth, surface area, root: shoot ratio and diameter below 60 cm. Geneotypes were catergoised into two major root forms based on root length distribution, 'Shallow' and 'Deep'. Assessment of genotypes registered since the inception of the breeding program showed an indirect selection for smaller roots with early maturity and increasing yield. Lentil varieties released for broadacre cropping in Australia have been selected for shoot architecture and yield, which has inadvertently resulted in variation in root architecture. Thus, these variations and plasticity in root architectural responses can be directly targeted for the future development of climate-ready crops. • Lentil breeding has produced genotypes with early maturity and greater yields. • Breeding for better shoot and yield traits has indirectly selected smaller roots. • Genotypes differed significantly in both shoot and root traits. • Late maturing genotypes accumulated more shoot and root biomass. • Root biomass had a negative impact on yield traits under optimum conditions. [ABSTRACT FROM AUTHOR]

The objective of this research was to characterize the high level of resistance to stripe that has been observed in the released wheat cultivar, Chuanmai45. A combination of classic genetic analysis, molecular and cytogenetic methods were used to characterize resistance in an F₂ population derived from Chuanmai45 and the susceptible Chuanmai42. Inheritance of resistance was shown to be conferred by two genes in Chuanmai45. Fluorescence in situ hybridization (FISH) was used along with segregation studies to show that one gene was located on a 1RS.1BL translocation. Molecular markers were employed to show that the other locus was located on chromosome 4B. The defeated gene, Yr24/26, on chromosome 1BL was present in the susceptible parent and lines that recombined this gene with the 1RS.1BL translocation were identified. The germplasm, loci, and associated markers identified in this study will be useful for application in breeding programs utilizing marker-assisted selection.