Chickpea (Cicer arietinum L.) is an important grain legume that is grown and consumed all over the world. Chickpea is mostly grown in rainfed areas and marginal soils with low available zinc (Zn); however, its productivity is affected by micronutrient deficiencies in soil, particularly Zn deficiency. Zinc is a structural constituent and regulatory cofactor of enzymes involved in various plant biochemical pathways. As such, Zn deficiency impairs plant growth and development by reducing enzyme activity, disturbing ribosomal stabilisation, and decreasing the rate of protein synthesis. Moreover, Zn deficiency induces flower abortion and ovule infertility, leading to low seedset and substantial yield reductions. Nonetheless, inclusion of chickpea in cropping systems (e.g. rice–wheat), either in rotation or intercropped with cereals, improves Zn availability in the soil through the release of phosphatases, carboxylates, and protons by roots and soil microbes. This review discusses the role of Zn in chickpea biology, various factors affecting Zn availability, and Zn dynamics in soil and chickpea-based cropping systems. The review also covers innovative breeding strategies for developing Zn-efficient varieties, biofortification, and agronomic approaches for managing Zn deficiency in chickpea. Strategies to improve grain yield and grain Zn concentration in chickpea through use of different Zn-application methods—soil, foliar and seed treatments—that are simple, efficient and cost-effective for farmers are also discussed. Screening of efficient genotypes for root Zn uptake and translocation to the grain should be included in breeding programs to develop Zn-efficient chickpea genotypes.

Objective guidelines about plant population are essential to ensure that yield potential of rice grain is not compromised. Drill-sowing of rice is increasing in popularity in many rice-growing regions of the world in response to a requirement for increased water productivity, but little information is available on row-spacing widths required to maximise grain yield potential. This research investigated the impacts of plant population on grain yield and yield components for aerial- and drill-sown rice, and the effects of row-spacing width for drill-sown rice grown in a temperate environment. Ten aerial-sown and five drill-sown experiments were conducted in south-eastern Australia over three seasons using four semi-dwarf rice varieties. Plant populations ranged from 7 to 396 plants m^–2.

Plant populations as low as 30 plants m^–2 were able to achieve grain yields >12 t ha^–1 but only when the plants were uniformly distributed. At a population of ∼100 plants m^–2, the impact of plant-stand distribution was negligible. Grain yield was maintained across a large range of plant populations, mainly through compensatory effects of more tillers per plant and more grains per panicle at lower plant populations.

For aerial-sown rice, maximum grain yield (up to 14.9 t ha^–1) was always achieved with a minimum plant population of 100 plants m^–2, and likewise for drill-sown rice provided the row spacing was ≤27 cm. At equivalent plant populations, 36-cm row spacing produced lower grain yield than narrower row spacings. When large gaps existed between plants within the rows, neighbouring plants could not compensate for the gap at the wider 36-cm row spacing, and grain yield was reduced. A practical optimal plant population of 100–200 plants m^–2 was found to be suitable for the semi-dwarf varieties used in this study for both aerial- and drill-sowing methods.

Canola (Brassica napus L.) is grown on >8 Mha in Canada and is sensitive to high temperatures; therefore, research on breeding methodologies to improve heat-stress tolerance is warranted. This study utilised a doubled-haploid population created from two parents (PB36 and PB56) that differed in their ability to set seed following growth at high temperatures. The experiment was designed to identify potential quantitative trait loci (QTLs) responsible for conferring tolerance to increased temperatures, and to utilise this population as a test case for evaluating the prospects of whole-genome prediction. The population was phenotyped in a split-plot, randomised complete block experimental design at three locations with two planting-date treatments. The first planting date was during the normal planting period (control), and the second planting was timed to experience increased average temperatures (1.7°C, 2.0°C and 1.2°C) and increased number of days with maximum temperatures above the critical temperature of 29.5°C (4, 12 and 3 days). The stress treatment reduced yield on average by 16.7%. There were 66 QTLs discovered across the nine traits collected. Given the quantitative nature of the traits collected, the ability to use whole-genome prediction was investigated. The prediction accuracies ranged from 0.14 (yield) to 0.66 (1000-seed weight). Prediction had higher accuracy within the stress treatment than within the control treatment for seven of the nine traits, demonstrating that phenotyping within a stress environment can provide valuable data for whole-genome predictions.

Water-soluble protein concentration (WSPC) of soybean (Glycine max (L.) Merrill) is an important factor affecting the quality of soybean-derived food and the aesthetic appearance of soybean products. In the present study, a representative soybean population of 178 elite accessions was used to determine quantitative trait nucleotides of WSPC via a genome-wide association study (GWAS). In total, 33 149 single-nucleotide polymorphisms (SNPs) with minor allele frequencies ≥5% and missing data ≤10% were applied in assessing the level of linkage disequilibrium. Finally, three association signals were identified related with WSPC through GWAS, including one novel locus and two known loci that overlapped the genomic region of reported quantitative trait loci. Thirty candidate genes located in the 200-kb genomic region of each peak SNP were detected and mainly grouped into the classes of protein synthesis/modification/degradation, RNA regulation of transcription, amino acid synthesis/metabolism, transport, hormone metabolism, signalling, development, lipid metabolism, and secondary metabolism. Through a gene-based association, 21 SNPs from eight genes were detected. Among them, four genes have been recognised as significant factors in mediating WSPC. The loci identified with beneficial alleles and candidate genes may be of great value for further functional analysis and marker-assisted selection of WSPC in soybean.

Lodging can reduce grain yield and quality, especially in crops planted at high densities. Force analysis, which relates stem mechanical properties and morphological characteristics under high densities, was used to study lodging in soybean (Glycine max (L.) Merr.). We applied mechanical lodging and examined the relationships between stem bending moment of the breaking force and morphological characteristics in two soybean varieties of contrasting heights grown at four crop population densities (200 000, 300 000, 400 000 and 500 000 plants ha^–1). The experiment was performed in a split-plot design during 2015–16. Measurements were made during the R1–R8 growth stages. Results showed that the full seed stage was the most sensitive period for lodging. Stem strength of the soybean plants increased with growth and development; however, during the R5–R6 stages, the weakened degree of stem strength was greater than the gravity moment. This was the primary reason for the soybeans tending to lodge during this period. In addition, increasing the planting density weakened the mechanical properties significantly. During breeding efforts to improve the soybean lodging resistance, more attention should be paid to strengthening soybean stems. This study also showed that the ratio of stem diameter to plant height could be a new quantitative index for evaluating the lodging resistance of soybeans.

Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc), is a widespread disease in citrus-producing areas of the tropics and subtropics. It is a serious threat to most commercial citrus cultivars and species. In this study, aggressiveness of different isolates of Xcc was determined on leaves of Citrus aurantiifolia, Citrus limon ‘Eureka’ and Citrus sinensis, and the population dynamics of isolates of two Xcc pathotypes (A and A*) was evaluated on eight plant species considered weeds of citrus, including Amaranthus caudatus, Medicago sativa, Sorghum halepense, Xanthium strumarium, Portulaca oleracea, Avena ludoviciana, Plantago lanceolata and Chenopodium album under greenhouse conditions. Isolates varied from aggressive to weakly aggressive on the basis of the intensity and persistence of water soaking and the development of necrosis 12 days post-inoculation. Both Xcc pathotypes multiplied on all plant species tested except Portulaca oleracea up to 20 days post-inoculation under greenhouse conditions. A high bacterial growth rate was observed on Medicago sativa and Plantago lanceolata. Strains of the A* pathotype successfully proliferated on all weeds except Portulaca oleracea, attaining a population density even higher than that of the A pathotype. The results clearly suggest that weed management is an important strategy in controlling canker disease in citrus-growing areas.

Brassica tournefortii Gouan. (wild turnip, WT) has become a problematic weed in the no-till production systems of the northern grains region of Australia. Experiments were undertaken using different biotypes of B. tournefortii to examine its phenology, emergence and seedbank persistence. Biotypes were obtained from paddocks of barley (Hordeum vulgare L.) (WT1 and WT9) and chickpea (Cicer arietinum L.) (WT1/17 and WT2/17). Fresh seeds initially had high dormancy rates and persisted for a short period on the surface. Seedbank persistence increased with burial depth, with 39% of seeds remaining for WT1 and 5% for WT9 after 30 months at 2 cm depth. Persistence of buried seeds varied across biotypes; WT1/17 seedlings also emerged in the second growing season from 2 cm depth. Compared with buried seeds, seedlings readily emerged from the surface (in March–June following increased rainfall) within 6 months of planting. Emergence was greatest on the surface and varied between biotypes and tillage systems; the highest rate recorded was ∼14%. Multiple cohorts were produced between February and October. No-till systems produced higher emergence rates than conventional tillage systems. Seedlings of B. tournefortii did not emerge from 5 cm soil depth; therefore, diligent tillage practices without seedbank replenishment could rapidly reduce the presence of this weed. A soil-moisture study revealed that at 25% of water-holding capacity, B. tournefortii tended to produce sufficient seeds for reinfestation in the field. Brassica tournefortii is a cross-pollinated species, and its wider emergence time and capacity to produce enough seeds in a dry environment enable it to become widespread in Australia. Early cohorts (March) tended to have vigorous growth and high reproduction potential. This study found B. tournefortii to be a poor competitor of wheat (Triticum aestivum L.), having greater capacity to compete with the slow-growing crop chickpea. Therefore, control of early-season cohorts and use of rotations with a more vigorous crop such as wheat may reduce the seedbank. The information gained in this study will be important in developing better understanding of seed ecology of B. tournefortii for the purpose of developing integrated management strategies.

Five cultivars of Urochloa brizantha (Hochst. ex A.Rich.) R.D. Webster (syn. of Brachiaria brizantha) were evaluated for nutritional value and an anti-nutritional factor (protodioscin), in order to determine whether protodioscin content was correlated with reduced feed quality. We evaluated cvv. Arapoty, Paiaguas, Xaraes, Marandu and Piata and grouped the results into summer, autumn, winter and spring seasons. Protodioscin content and chemical composition of leaves, in vitro digestibility and cumulative gas production were analysed. Data were evaluated by analysis of variance as a completely randomised experimental design in a factorial arrangement (five cultivars × four seasons). There was no significant interaction between cultivar and season. All grasses showed highest protodioscin contents during autumn. Protodioscin contents ranged from 5.6 g kg^–1 (spring) to 19.2 g kg^–1 (autumn). Crude protein content varied significantly across seasons. No significant effect was detected for neutral detergent fibre (NDF) content among seasons. Cultivar Arapoty showed the highest NDF content in summer (669.3 g kg^–1) and the lowest in spring (601.9 g kg^–1). The best in vitro digestibility coefficients were observed in spring. The protodioscin content of U. brizantha cultivars can negatively affect their digestibility and some parameters of cumulative in vitro gas production.

Changes in sward height of pastures managed by continuous grazing according to climatic seasonality may alter tillering and forage production. In order to evaluate the feasibility of seasonal alteration in sward height of Marandu palisade grass pastures (Brachiaria brizantha (Hochst. ex A.Rich.) R.D. Webster; syn. Urochloa brizantha (A.Rich.) Stapf) under continuous grazing management, we studied two constant sward heights (15 cm and 30 cm), and one height that was initiated at 30 cm, reduced to 15 cm in June (dry and cold season) and returned to 30 cm in December (wet and hot season) (30–15–30 cm). Pastures managed at 30–15–30 cm had a greater tiller appearance rate (22 tillers/100 tillers.30 days) than those maintained at 15 cm and 30 cm (16 and 17 tillers/100 tillers.30 days, respectively). In the 30–15–30 cm pastures, a lower accumulation rate of dead material was observed during the dry and cold season (June–August), which resulted in a higher leaf and lower dead material accumulation rate during the second growth season (wet and hot season, December–January). Planned reduction in sward height during the cold season can be used safely because it permits better seasonal distribution and utilisation of forage production without compromising the stability of Marandu palisade grass pastures.

The effects of nitrogen (N) fertiliser rate and irrigation on seed yield and its components were evaluated for signal grass (Urochloa decumbens (Stapf) R.D. Webster; syn. of Brachiaria decumbens Stapf) cv. Basilisk in a field experiment in Umuarama, Paraná, Brazil. Two water regimes (irrigated and non-irrigated) and four nitrogen (N) fertiliser rates (0, 25, 50 and 75 kg ha^–1) were applied to perennial signal grass crops in a split-plot randomised complete block design with three replications. In two consecutive harvests, favourable rainfall resulted in irrigation having limited influence on most measurements, and the combined application of irrigation and N fertiliser did not improve seed yield. Compared with the nil N, the highest N application rate significantly increased seed yield for the first crop (266 vs 498 kg ha^–1) and the second crop (104 vs 286 kg ha^–1). Nitrogen fertilisation significantly increased number of seed per area, reproductive tiller density and plant biomass at harvest for the first and second crops. Harvest index, 1000-seed weight, reproductive tiller weight, number of spikelets per panicle and number of seeds per panicle were unaffected by N rate. Harvest index ranged from 1.10% to 3.63% and 1000-seed weight from 2.15 to 3.36 g. There were no treatment effects on number of days to flowering or anthesis. Fertilisation with 75 kg N ha^–1 for the first crop and 50–75 kg N ha^–1 for the second crop maximised signal grass seed yield.