The wheat NAM-B1 and NAM-A1 genes are positively associated with grain protein content (GPC) in wheat. We conducted molecular characterisation of the NAM-1 genes in 51 Australian wheat varieties (Triticum aestivum L.), with the aim of improving GPC and nitrogen-usage efficiency in Australian wheat. In summary, the wild type NAM-B1 gene, which originated from Israel, was identified in two Australian wheat varieties. Five varieties contained a deletion allele, whereas the majority (43) harboured a non-functional NAM-B1 allele and one variety contained both functional and non-functional alleles. Twenty-six Australian wheat varieties contained the NAM-A1a haplotype, which was similar to its well-characterised homoeolog NAM-B1 wild type and associated with high GPC. The NAM-D1 gene in the 51 wheat varieties was also characterised, and no gene variation in the exon regions was noted; only two single-nucleotide polymorphisms in introns 1 and 2 were found among the 51 varieties.

Drought is a widespread abiotic stress that has a detrimental effect on both yield and quality of wheat. Discovery and utilisation of drought-resistant gene resources from wheat-related species may help to mitigate effects of drought and decrease yield loss. In this study, we used a comparative proteome approach to identify potential drought-resistance proteins from a wheat (Triticum aestivum L.)–Haynaldia villosa (L.) Schur 6VS/6AL translocation line. Drought experiments showed that introgression of the H. villosa 6VS chromosome short arm into common wheat cultivar Yangmai 5 through 6VS/6AL translocation led to better drought resistance. Two-dimensional difference gel electrophoresis (2D-DIGE) identified 99 differentially accumulated protein (DAP) spots in the wheat–H. villosa 6VS/6AL translocation line, 42 of which were specifically present or showed a significantly upregulated accumulation. Of these, 20 DAPs representing 19 unique proteins in the wheat–H. villosa 6VS/6AL translocation line were upregulated under drought stress. These proteins were mainly involved in defence–stress, energy metabolism, carbon metabolism, nitrogen metabolism, and protein metabolism or folding. Protein–protein interaction analysis of key DAPs displayed a complex interaction network that synergistically regulated drought response. Dynamic transcriptional expression analysis revealed the differential expression of six key DAP genes involved in drought-stress response in the protein–protein interaction network. Our results indicated that H. villosa may have gene resources for wheat drought-resistance improvement.

Water shortage is a limiting factor to crop production in North China. Mulching is a widely used approach to conserve soil water and improve crop yield. A 2-year field experiment was conducted at the Nanpi Eco-Agricultural Experimental Station of the Chinese Academy of Sciences in 2014–16, in which yields of winter wheat (Triticum aestivum L.) in a treatment with subsoil plastic film mulch were compared with non-mulch. The mulch treatment produced a 16.1% higher grain yield than the non-mulch treatment. The increase in grain yield was primarily due to a 10.1–10.9% increase in number of spikes per m² and a 4.7–5.1% increase in number of grains per spike. Plants in the mulch treatment showed greater dry matter (DM) accumulation but similar harvest index. Yield improvement did not depend on increasing DM translocation, but was significantly related to DM accumulation at different growth stages. Increased DM accumulation before wintering, from jointing to heading and from anthesis to maturity, enhanced grain yield by promoting increased number of spikes and number of grains per spike. Soil evaporation was lower by 31.1% and transpiration increased by 28.0% in the mulch treatment, resulting in 8.9–9.4% higher water-use efficiency. Our results indicate that a subsoil plastic film mulch can effectively improve winter wheat yield and water-use efficiency under rain-fed conditions.

This study explored the effects of abiotic stress on anthocyanin accumulation and grain weight of purple wheat (Triticum aestivum L. cv. Guizi 1). Plants were treated with five abiotic stress factors at different developmental periods of the grain, then mature grains were analysed for anthocyanin content and 1000-grain weight (TGW). Stresses included temperature (cold and heat), light (shading irradiance and continuous irradiance), drought (20 and 40 mm PEG 6000), salinity (100 and 200 mm NaCl), and wounding (four types). Of all treatments, 25% tended to increase both anthocyanin content and TGW, although only 5% reached a significant level, 27.5% decreased both, 40% increased anthocyanins but decreased TGW, and 7.5% increased TGW but decreased anthocyanins. Heat stress tended to increase anthocyanin content and decrease TGW, whereas cold stress increased anthocyanins only at 15 days post-anthesis (DPA) and decreased both traits at other times. Shading irradiance decreased anthocyanins but had little effect on TGW. Continuous irradiance increased anthocyanins and TGW at 35 DPA but decreased both at 10 DPA. The lower levels of drought (20 mm PEG 6000) and salinity (100 mm NaCl) stress tended to increase anthocyanins and decrease TGW; however, the effects of 40 mm PEG 6000 and 200 mm NaCl were different, and were period-dependent. The four types of wounds increased anthocyanins and TGW at 30 DPA, but their individual effects were different in the other four periods. The results quantified the effects of five abiotic stress factors on anthocyanin accumulation and grain weight, and provide the foundation for further study of defence-responsive molecular mechanisms of abiotic stress in purple wheat.

Barley (Hordeum vulgare L.) is often grown in sites with low rainfall and high temperature during grain filling. Because spike architecture is one of basic footprints of barley domestication, the importance of spikes in adaptation to different environments or abiotic stresses can be hypothesised. In order to compare different barley spike types in terms of kernel growth and yield components, we tested 15 two-row and 10 six-row winter genotypes in eight environments where terminal drought was simulated by defoliation at 7 days after heading (7 DAH). Control plants were grown intact. On average, two-row genotypes outyielded six-row genotypes by 17% under control conditions and 33% under simulated late drought. Observations of kernel dry weights from 7 DAH through to harvest maturity at 5-day intervals were regressed onto a measure of thermal time. After preliminary evaluation of four nonlinear (S-shaped) models for kernel dry-weight accumulation, the ordinary logistic model was deemed the most appropriate in most cases and was finally applied to all plant-growth curves. Four parameters were estimated from the logistic model. Whereas two earliness estimators (inflection point and thermal time needed to reach maximum kernel weight) were similar for the two barley types, maximum kernel weight (Y_max) and mean rate of kernel growth (RG) were higher (P < 0.05) in two-row than in six-row barleys. Differences in Y_max and RG among six-row barley genotypes were greater between control and defoliation treatments than between years, whereas among two-row barley genotypes, differences between years were greater, suggesting better stability of six-row types and better drought tolerance of two-row types in the tested barley set.

Lactic acid bacteria (LAB) can be used as silage additives to ensure rapid and vigorous fermentation at early stages of ensiling. We predicted that the optimal LAB inoculation dosage for forage at ambient temperature (15–38°C) would be different from that at cold temperature (4°C). In this study, Lactobacillus plantarum QZ227, isolated from a wheat landrace in alpine regions of Qinghai, China, and commercial L. plantarum FG1 were used as inoculum, with sterile water as control. The effects of inoculum dosage on the fermentation quality of oat (Avena sativa L. cv. Qinghai) and wheat (Triticum aestivum L. cv. Yumai No. 1) silage at ambient temperature (15–38°C) and at 4°C were investigated in laboratory experiments. Little or no improvement in silage quality occurred upon increasing the inoculum dosage at ambient temperature. By contrast, a lower pH and NH₃-N content, and a higher LAB count and lactic acid content, were observed at 4°C. Furthermore, the growth of Escherichia coli was inhibited effectively at the lower temperature, and silage quality was positively correlated with increasing inoculum dosage (P < 0.05). These results suggest that increasing the inoculum dosage could improve the quality of silage at lower temperatures of 4°C, whereas an appropriate dosage was a key factor for silage at ambient temperature. In this study, oat forage could be used as raw materials for ensiling only at low temperature but was not suitable for ensiling at ambient temperature without wilting due to the high moisture content (86.55%). QZ227 isolated from the roots of wheat in alpine regions displayed superior antimicrobial properties against yeast at ambient temperature and E. coli at 4°C compared with commercial strain FG1. This is the first study to explore the effects of inoculum dosage on silage quality at low temperatures, and provides a basis for low-temperature silage technologies.

Breeding for improved blanchability—the propensity of the testa (skin) to be removed from the kernel following rapid heat treatment—is a priority for improvement in the Australian Peanut Breeding Program (APBP). Easy removal of the testa by blanching is required for processing of peanuts into peanut butter and various other confectionary products. Thus, blanchability is an economically important trait in any newly released cultivar in Australia. A better understanding of the range of genetic variation, nature of inheritance and genotype × environment (G×E) interactions, and the development of a low-cost method to phenotype in early generations, could speed up breeding for this trait. Studies were conducted to develop a low-cost, rapid method utilising minimal amounts of seed to phenotype in early generations, along with an assessment of G×E interactions over a range of years and environments to derive optimal selection protocols. Use of a smaller kernel sample size than standard (50 vs 200 g) was effective for accurately assessing blanchability in breeding lines and could allow selection in early generations (e.g. in seed produced from a single F₂ plant where seed supply is adequate). G×E interaction for blanchability was shown to be very low. Genotypic variance explained 62–100% of the total variance for blanchability, assessed in two diverse germplasm pools including 107 accessions in the USA mini-core over three environments and multiple APBP breeding lines grown over nine different years–environments. Genotypic correlations between all environments were very high (∼0.60–0.96), with heritability for the blanchability trait estimated to be very high (0.74–0.97) across the 13 trials. The results clearly demonstrate that effective selection for improved blanchability can be conducted in early generations and in a limited number of contrasting environments to ensure consistency of results.

Soluble sugar content in silique wall and seeds of rapeseed (Brassica napus L.) has significant effects on seed oil formation and accumulation. We studied the relationship between soluble sugar content in B. napus seeds and silique wall and oil concentration under field conditions in two cropping seasons, and examined changes in soluble sugar content in seeds and silique wall under different nitrogen (N) levels. Two commercialised Chinese rapeseed varieties, HZ9 and HZ62, with high seed yield and different N responses were used. Our results indicated that carbon (C) : N ratio and soluble sugar content in silique wall had the greater effect on seed oil concentration. When C : N ratio and soluble sugar content in silique wall were within 5–15% and 10–25%, respectively, plants had relatively well coordinated C and N metabolism, facilitating oil accumulation. During 25–35 days of silique development, when C : N ratio and soluble sugar content in silique wall were within 10–15 and 15–25%, respectively, oil synthesis was fastest; the highest accumulation rate was 3.8% per day. When they were each <5%, seeds tended to mature, and oil synthesis gradually decreased, ceased or degraded. During the early stage of silique development, if C : N ratio and soluble sugar content in silique wall were >15% and 30%, there was no apparent tendency for oil accumulation, probably because of adverse environmental conditions. When N application increased from 0 to 270 kg ha^–1, final oil concentration in seeds decreased by 0.024%. In summary, C : N ratio and soluble sugar content in silique wall are important in regulating seed oil concentration, whereas excessive N application significantly reduced seed oil concentration. Therefore, appropriate reduction of N application would save resources, provide environment benefits and increase rapeseed oil production with no substantial reduction in seed yield, through coordinated seed yield and oil concentration.

Agronomic and seed-quality traits in 17 quinoa (Chenopodium quinoa Willd.) accessions grouped according to seed colour (i.e. ochre and yellow) were investigated and compared with the white commercial cultivar Regalona-Baer. These accessions were previously selected from a range of accessions of diverse origin and seed colour for their potential value in a breeding program for cultivars adapted to the southern Italian environment. Field trials were conducted over 2 years in Foggia, southern Italy. The aim was to identify elite genotypes suited to the Mediterranean Basin in terms of high yields and seed quality, by using principal component analysis (PCA) and hierarchical cluster analysis. The genotype and year effects were statistically significant for most parameters investigated, whereas the genotype × year interaction was significant only for seed quality. There were significant differences between the two seed-colour groups for most of the investigated traits, but not for total dry weight, days to flowering, and soluble and insoluble fibre. The major difference between the accessions and cv. Regalona-Baer was lower seed yield for the ochre seed group (30% lower, on average); this was associated with increased plant height (13% higher, on average), greater number of days to maturity ( 6 days, on average) and shorter panicle length (21% shorter, on average). These results were observed for both growing seasons. The seed yield of the yellow seed group was similar to Regalona-Baer. Focusing on individual accessions, PCA indicated that accessions Q12, Q18 and Q26 were similar to Regalona-Baer for seed yield, 1000-seed weight, seed area and seed perimeter, and accession Q4 had the highest protein and kaempferol contents for both years. Seed area and perimeter, harvest index, and 1000-seed weight showed positive associations with seed yield, whereas days to flowering, days to maturity and quality traits were negatively correlated with seed yield for both years. Cluster analysis carried out on all of the agronomic and seed-quality traits did not show clear clustering of the accessions based on seed colour alone. The results of this study confirm that both the ochre and yellow quinoa seed groups included elite accessions that can be used directly in future selection programs for the development of high-yielding varieties well adapted to the Mediterranean environment.