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Algae, including seaweeds and microalgae, contribute nearly 30 percent of world aquaculture production (measured in wet weight), primarily from seaweeds. Seaweeds and microalgae generate socio-economic benefits to tens of thousands of households, primarily in coastal communities, including numerous women empowered by seaweed cultivation. Various human health contributions, environmental benefits and ecosystem services of seaweeds and microalgae have drawn increasing attention to untapped potential of seaweed and microalgae cultivation. Highly imbalanced production and consumption across geographic regions implies a great potential in the development of seaweed and microalgae cultivation. Yet joint efforts of governments, the industry, the scientific community, international organizations, civil societies, and other stakeholders or experts are needed to realize the potential. This document examines the status and trends of global algae production with a focus on algae cultivation, recognizes the algae sector's existing and potential contributions and benefits, highlights a variety of constraints and challenges over the sector's sustainable development, and discusses lessons learned and way forward to unlock full potential in algae cultivation and FAO's roles in the process. From a balanced perspective that recognizes not only the potential of algae but also constraints and challenges upon the realization of the potential, information and knowledge provided by this document can facilitate evidence-based policymaking and sector management in algae development at the global, regional and national levels. [ABSTRACT FROM AUTHOR]

Drought stress, especially at the reproductive stage, is a major limiting factor that compromises the productivity and profitability of canola in many regions of the world. Improved genetics for drought tolerance would enable the identification and development of resilient cultivars, resulting in increased canola production. The main objective of the present study was to dissect the genetic basis of seed yield of canola under water-limited conditions. A doubled haploid population derived from a cross between two Australian parental lines, RP04 and Ag-Outback, was evaluated to identify the genetic variation in fractional normalised deviation vegetative index (NDVI), aboveground shoot biomass accumulation, flowering time and plasticity in seed yield under irrigated and rainfed field conditions in two consecutive years. An irrigation treatment was applied at the 50% flowering stage and an incremental drought tolerance index (DTI) was estimated for seed yield. By utilising a genetic linkage map based on 18851 genome-wide DArTseq markers, we identified 25 genomic regions significantly associated with different traits (logarithm of odds (LOD) ≥ 3), accounting for 5.5–22.3% of the genotypic variance. Three significant genomic regions on chromosomes A06, A10 and C04 were associated with DTI for seed yield. Some of the quantitative trait loci (QTL) were localised in the close proximity of candidate genes involved in traits contributing to drought escape and drought avoidance mechanisms, including FLOWERING LOCUS T (FT) and FLOWERING LOCUS C (FLC). Trait-marker associations identified herein can be validated across diverse environments, and the sequence-based markers may be used in a marker assisted selection breeding strategy to enhance drought tolerance in canola breeding germplasm.

In recent decades several pasture legumes have been available in southern Australia as potential alternatives to the most widely used annual pasture legume Trifolium subterraneum. Little is known about their soil phosphorus (P) requirements, but controlled environment experiments indicate that at least some may differ in their P fertiliser requirements. In this study, pasture legume varieties, including T. subterraneum as the reference species, were grown at up to four sites in any one year over a 3-year period (in total, seven site × year experiments) to measure herbage growth responses in spring to increased soil P availability. A critical soil test P concentration (corresponding to 95% maximum yield) was estimated for 15 legumes and two pasture grasses. The critical soil P requirements of most of the legumes did not differ consistently from that of T. subterraneum, indicating their soil fertility management should follow the current soil test P guidelines for temperate Australian pastures. However, the critical P requirement of Medicago sativa was higher than that of T. subterraneum, but remains ill-defined because extractable soil P concentrations in these experiments were often not high enough to permit a critical P estimate. Three forage crop legumes (Trifolium incarnatum, Trifolium purpureum, Trifolium vesiculosum) and two pasture legumes (Ornithopus compressus, Ornithopus sativus) had lower critical soil test P concentrations. It may be feasible to manage pastures based on these species to a lower soil test P benchmark without compromising yield.

High yield is a major objective in canola-breeding programs. We analysed the genetic determinants controlling variation in grain yield in a doubled-haploid (DH) breeding population derived from a single BC1F1 plant from the cross Skipton/Ag-Spectrum//Skipton (designated as the SAgS population). DH lines were evaluated for flowering time and yield in two replicated trials and exhibited significant genetic variation for both traits. Yield showed negative correlation with flowering time; lines that flowered earlier had higher yield than late-flowering lines. A genetic linkage map comprising 7716 DArTseq markers was constructed for the SAgS population, and a ‘bin’ map based on 508 discrete single-position (non-co-segregating) marker loci was used for quantitative trait locus (QTL) analysis. We identified 20 QTLs (LOD ≥2) associated with variation in flowering time and grain yield. Two QTLs (Qy.wwai-A7/Qdtf.wwai-A7/Qfs.wwai-A7 and Qy.wwai-C3a/Qfs.wwai-C3a) appeared repeatedly across experiments, accounting for 4.9–19% of the genotypic variation in flowering time and yield and were located on chromosomes A07 and C03. We identified 22 putative candidate genes for flowering time as well as grain yield, and all were located in a range of 935bp to 2.97 Mb from markers underlying QTLs. This research provides useful information to be used for breeding high-yielding canola varieties by combining favourable alleles for early flowering and higher grain yield at loci on chromosomes A07, C03 and possibly on A06.

Conservation cropping systems with no-till and stubble retention improve soil condition and water conservation. However, tillage is replaced by herbicides for weed control in these systems, increasing the threat of herbicide resistance. In the medium to high rainfall zones of the southern wheatbelt of Australia and under irrigation, wider row spacing is used to enable seeding into heavy stubble loads and to avoid stubble burning. Some evidence suggests that wider rows lead to reduced crop competitive ability and crop yields, greater herbicide dependence, and increased spread of resistance. Our aim was to test the hypothesis that increasing seeding rate compensated for reduced competitive ability at wider row spacings, especially when herbicide performance was suboptimal. We examined the impact of two wheat row spacings (18 and 36cm) and five seeding rates (resulting in a range of densities of ~80–700 plants/m2) on control of Lolium rigidum with five rates of post-emergence application of diclofop-methyl (Hoegrass®), ranging from label rate to lower rates, over two growing seasons. In the presence of L. rigidum, wheat grain yield was unaffected by row spacing but was significantly reduced at low seeding rates, especially at lower herbicide rates. Lolium rigidum was suppressed at higher crop densities but was also unaffected by row spacing. Grain yield was maximised when post-emergence herbicide was applied at 60–100% of the recommended dose at wheat densities >~300 plants/m2. Significant levels of the weed remained in the crop at anthesis in all treatments. Weed dry matter ranged from 525g/m2 at low crop densities and with no herbicide to 150g/m2 with the recommended rate of herbicide and high wheat densities. The implications of manipulating crop competitive ability to improve weed control are discussed, especially in conditions where herbicide performance is unreliable due to weeds developing herbicide resistance or adverse environmental conditions.