In this study, the authentic high molecular weight glutenin (HMW-GS) allele Glu-B1 h encoding for subunits 1Bx14 and 1By15 from German bread wheat cultivars Hanno and Imbros was identified and cross-verified by a suite of established protein analysis technologies, including sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reversed-phase high-performance liquid chromatography, reversed-phase ultra-performance liquid chromatography, and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). The complete encoding sequences were isolated by allele-specific PCR, and consist of 2367 bp for 1Bx14 and 2151 bp for 1By15 and encode 789 and 717 amino acid residues, respectively. The deduced molecular masses of two subunit genes were 82 340.13 Da and 74 736.13 Da, corresponding well to those determined by MALDI-TOF-MS. The presence and authenticity of 1Bx14 and 1By15 subunits were further confirmed by liquid chromatography coupled to tandem mass spectrometry and heterologous expression in E. coli. Comparative analysis demonstrated that 1Bx14 possessed one deletion and 20 single-nucleotide polymorphism variations compared with seven other Glu-B1 x-type HMW-GS genes that mainly resulted from C–T substitutions, whereas compared with five other Glu-B1 y-type HMW-GS genes, 1By15 displayed few variations. Phylogenetic analysis based on the complete coding sequences of the published HMW-GS genes showed that 1Bx14 had a high divergence with other 1Bx subunit genes, whereas 1By15 displayed greater similarity with 1By20. A possible evolutionary route for 1Bx14 gene formation is proposed, which might have resulted from an intra-strand illegitimate recombination event that occurred ∼1.32 million years ago.

The root-lesion nematode, Pratylenchus thornei, can reduce wheat yields by >50%. Although this nematode has a broad host range, crop rotation can be an effective tool for its management if the host status of crops and cultivars is known. The summer crops grown in the northern grain region of Australia are poorly characterised for their resistance to P. thornei and their role in crop sequencing to improve wheat yields. In a 4-year field experiment, we prepared plots with high or low populations of P. thornei by growing susceptible wheat or partially resistant canaryseed (Phalaris canariensis); after an 11-month, weed-free fallow, several cultivars of eight summer crops were grown. Following another 15-month, weed-free fallow, P. thornei-intolerant wheat cv. Strzelecki was grown. Populations of P. thornei were determined to 150 cm soil depth throughout the experiment. When two partially resistant crops were grown in succession, e.g. canaryseed followed by panicum (Setaria italica), P. thornei populations were <739/kg soil and subsequent wheat yields were 3245 kg/ha. In contrast, after two susceptible crops, e.g. wheat followed by soybean, P. thornei populations were 10 850/kg soil and subsequent wheat yields were just 1383 kg/ha. Regression analysis showed a linear, negative response of wheat biomass and grain yield with increasing P. thornei populations and a predicted loss of 77% for biomass and 62% for grain yield. The best predictor of wheat yield loss was P. thornei populations at 0–90 cm soil depth. Crop rotation can be used to reduce P. thornei populations and increase wheat yield, with greatest gains being made following two partially resistant crops grown sequentially.

Confectionery sunflower (Helianthus annuus L.) has been cultivated in Spain for many years in small vegetable gardens for self-consumption, and this has created a vast genetic diversity of local landraces. The objective of this research was to assess variation in seed quality traits in a germplasm collection of Spanish local landraces of confectionery sunflower. Seed weight, kernel percentage, oil content, fatty acid composition, squalene, tocopherol and phytosterol contents, and tocopherol and phytosterol composition, were analysed in 137 landraces grown for 2 years in Córdoba, Spain. The evaluation was hindered by large differences for flowering time between accessions (>90 days), which made it difficult to separate genetic from environmental effects. The collection contained large variability for all traits evaluated. Of particular relevance were the ranges of variation (2-year averages) for squalene content (12–128 mg kg^–1 seed kernel), tocopherol content (114–423 mg kg^–1 seed kernel) and Δ⁷-stigmastenol content (7.1–35.2% of total phytosterols). Some traits were associated with specific locations; for example, all seven accessions collected in Espiel (Córdoba province) had high Δ⁷-stigmastenol content, although they differed for other traits. Some of the accessions evaluated in this research are valuable genetic sources for breeding programs focusing on seed and oil quality in sunflower.

Little information currently exists on the relationship between rhizobial symbiosis and mineral accumulation in nodulated legumes. The aim of this study was to measure fixed nitrogen (N) in whole plants and in young fully expanded trifoliate leaves of cowpea genotypes, and to relate this to mineral accumulation in the leaves. The data revealed marked differences between high and low N₂-fixing genotypes, with the former consistently showing greater %N, plant or leaf total N, and amount of N fixed compared with the latter. There was a 2.0–3.8-fold difference in amount of N fixed at whole-plant level between high- and low-fixing cowpea genotypes at Taung, South Africa, and 2.4–4.0-fold at Manga, Ghana. Furthermore, the genotypes with high N₂ fixation consistently exhibited greater concentration and content of minerals (e.g. P, K, Mg, S, Na, Fe, Cu, Zn, Mn and B) in their trifoliate leaves, whereas those that recorded low N₂ fixation accumulated lesser amounts of mineral nutrients in leaves. In a nodulation assay, we found that rhizobial isolates TUT53b2vu and TUT33b4vu, which exhibited higher symbiotic efficiency (measured here as nodule number, nodule fresh weight, and plant dry matter yield), also elicited greater mineral accumulation in cowpea shoots, while strains with low N₂-fixing ability induced limited mineral accumulation. These results, together with a correlation analysis, show that, at least in nodulated cowpea, there is a strong relationship between N₂-fixing efficiency and mineral accumulation, two traits that could be exploited in breeding programs for improved human nutrition and health.

Growing location and genotypes are known to affect the subunit composition of the major storage proteins of soybeans, β-conglycinin (7S globulins) and glycinin (11S globulins), which have been associated with tofu quality. In this study, we examined 16 soybean genotypes grown at two locations in Queensland, Australia, for the influence of globulin subunit composition, growing location and genotype × growing location interaction on seed, soymilk and silken tofu properties. These genotypes comprised four groups: with all globulin subunits, without 11SA4, without 7Sα’, or without 11SA4 and 7Sα’. There were significant differences in the major protein subunits among the genotypes and the four groups and between locations. Significant genotypic and location differences were also observed in the properties of the seed, soymilk and silken tofu. There were no significant genotype × location interactions. The group without 11SA4 had less 11S and more 7S globulins, resulting in the lowest 11S/7S ratio. The silken tofu from this group had firmer texture and less water loss than the group containing all globulin subunits. The results suggested that genotypes of differing globulin subunit composition may produce tofu with different qualities and the effect of globulin subunit composition on tofu quality could be affected by growing location and the absence of certain globulin subunits.

Soybean variety Bunya was developed in Australia to provide a better quality bean for tofu manufacturers. It is null for globulin subunit 11SA4. We investigated the effect of both the Bunya genetic background and the11SA4 subunit on tofu properties using genotypes containing 11SA4, with and without Bunya parentage, or lacking 11SA4 with Bunya parentage. Both Bunya parentage and 11SA4 significantly influenced globulin subunit composition and tofu texture. The group lacking 11SA4 had lower seed protein content, the largest seeds and the highest 7S and the lowest 11S content and produced the hardest tofu. Examination of the impact of 11SA4 null on tofu texture at four protein contents (380–440 g kg^–1) over four coagulant (2.0–3.5 g kg^–1) levels revealed that the absence of 11SA4 produced firmer tofu across the protein and coagulation levels tested, and this difference was larger than that from higher protein or coagulation levels. These results demonstrated that the absence of the 11SA4 subunit could increase tofu hardness to a level that otherwise could only be achieved with much higher seed protein content.

This study was designed to examine effects of high temperature, drought and exogenous abscisic acid (ABA) on membrane stability, osmotic adjustment, photosynthesis and the hormone status of two lucerne (alfalfa, Medicago sativa L.) genotypes contrasting in heat tolerance: Ameristand 801S (AS801) (heat-tolerant), and Aohan (heat-sensitive), The results showed that AS801 had lower electrolyte leakage, but higher chlorophyll content, net photosynthetic rate, stomatal conductance, proline content, ABA content and zeatin riboside (ZR) content than Aohan during 72 h of heat stress under well-watered conditions. Under drought conditions, however, only proline content and ZR content in roots, electrolyte leakage in leaves and roots, net photosynthetic rate, and ABA content were significantly different between the two genotypes. A foliar application of ABA to heat-stressed plants significantly decreased electrolyte leakage and stomatal conductance, and increased recovery in growth and leaf water potential in the two genotypes under both watering conditions. The other physiological responses measured differed under drought or well-watered conditions, and appeared to be genotype-specific. These results suggest that the physiological responses of heat-sensitive and heat-tolerant lucerne to heat stress under different soil-water conditions varied. The heat-induced changes in proline accumulation in roots, electrolyte leakage in leaves and roots, and photosynthetic rate could serve as early instant stress indicators for evaluating the tolerance of lucerne genotypes to heat stress under different soil water conditions.

Experiments were established in the Burdekin Irrigation Area in North Queensland, Australia, to measure whether yield improvements from breaking the sugarcane monoculture or fumigating the soil could be modified by the application of different rates of nitrogen (N) fertiliser. Experiments were conducted in consecutive crop cycles (phase 1, planted 1998; phase 2, planted 2001) using the variety Q117, with the interaction between N applications and rotation histories discussed for the two plant crops. Histories consisted of alternate crop, bare fallow or mixed grass–legume pastures for periods of 42–66 months, compared with continuous cane as plough-out replant without (PORP) or with (PORP-F) soil fumigation. The N strategies involved combinations of N rates (0–180 kg N/ha) and application times (at planting, 90 days after planting (DAP) or split between these times) in phase 1 and N rates (0–300 kg N/ha) in phase 2.

Histories had differing effects on N available to the cane crop and hence on response to N fertiliser. Some combinations of history and N rate were N-limited and strong linear relationships between biomass production or cane yield and crop N content could be developed. Critical N contents for biomass production (R² = 0.93) and fresh-weight cane yield (R² = 0.88) were 1.42 and 0.57 kg N/t, respectively. Application of N fertiliser was shown to have significant impacts on both tiller addition and the retention of tillers to produce harvestable stalks. However, the application of fertiliser N had limited (phase 1) or no (phase 2) capacity to provide the quantum of yield response in soil health benefits associated with breaking the sugarcane monoculture. Increasing N application rates above that required to optimise crop yield resulted in significant decreases in sugar content of cane and thus lower sugar yields. Yield increases solely from improved soil health (i.e. exclusive of N response) constituted advantages averaging 15% (phase 1) to 20% (phase 2) compared with PORP. These effects were manifest early in the establishment of primary shoots in the plant crops, although the longevity of these benefits was limited. Replanting cane after a 3-year crop cycle (plant, 1st and 2nd ratoon) on land that had been under pasture, crop, bare fallow or PORP-F histories (phase 2, cycle 2) showed carryover effects of histories on N availability and fertiliser N responsiveness, but limited yield impacts attributable to residual soil health benefits. These results reinforce the importance of crop rotation during breaks between sugarcane cycles to maintain soil health and improve crop productivity.

Sugarcane ripening is a process controlled by cultivar characteristics and the interaction of genotypes with local climate. The objective of this study was to characterise the temporal variation of sugarcane ripening by assessing the multivariate structure contained in sugarcane quality data, and by correlating the results with local climatic conditions. Eight sugarcane cultivars were evaluated from March to October in Piracicaba, São Paulo State, Brazil. Characteristics related to the quality of raw sugarcane juice were submitted to statistical analysis by ANOVA, hierarchical and non-hierarchical (k-means) clustering methods, and principal components, in order to classify the cultivars into groups for each month of sampling. The ANOVA showed a clear difference (P < 0.001) among harvesting months for all sugarcane quality variables, which was reinforced by the cluster analysis for the whole dataset that selected groups according to the month of harvest. By analysing the quality variables by months, patterns of similarity among sugarcane cultivars were identified, which allowed three ripening groups to be established: early, middle and late. As the harvesting season progressed, the variations within each group, as well as among groups, were explained mainly by local soil-water availability conditions. The early ripening cultivars showed polarisable sugar (Pol) values >13% in early May, whereas these values were reached by the middle cultivars in July, and the late ones in August–September. However, the differences among groups tended to decrease through the harvest season, as expressed by the Euclidean distance, which decreased from 5.62 in March to 1.82 in September, when the water deficit reached the maximum accumulated value, totalling >130 mm. The non-hierarchical analyses (k-means) and principal components methods agreed, resulting in the identification of the same three main cultivar groups. The approach proposed for cultivar classification in this study is more complete than the usual analysis of Pol variation over time, since it allowed all of the variability contained in the sugarcane quality dataset to be analysed in an integrated way, providing a better understanding of the differences observed in the ripening of different cultivars.