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Context: Reliable seed production is a key requirement for successful year-on-year regeneration of annual pasture legumes. Aims: The study aims were to investigate the developmental patterns of flowers and pods and the effect on seed number among cultivars of French (Ornithopus sativus Brot.) and yellow serradella (O. compressus L.); and to assess the effects of early flower loss. Methods: Four cultivars of each species were grown in a glasshouse under non-limiting growth conditions. Date of flowering and numbers of flowers, pods and seeds were assessed for up to 20 reproductive nodes on two stem axes per plant (n = 5 plants). A flower removal treatment was imposed to assess whether early flower loss affected flower and/or pod production. Key results: Flowering in the serradellas was indeterminate, but for all cultivars there was a peak period of flower and pod production, with the timing and duration of the peak period differing among cultivars. Peak flowering occurred primarily because the proportion of plants flowering began to decline, but the number of flowers per reproductive node and the number of pods formed per node also declined with time. Compensation for early flower loss was observed for most cultivars because of a longer duration of pod formation and/or greater numbers of pods developed on higher reproductive nodes. Conclusions: This study demonstrated that there is diversity in the patterns of flowering and podding and number of seeds initiated among serradellas. Implications: Diversity in flowering and podding patterns combined with a capacity to compensate for early flower loss may be used to develop serradellas better able to cope with environmental stressors (frost, drought, heat) experienced during the flowering window. To ensure the continued existence of annual legume species in temperate regions, it is essential to understand the factors contributing to successful seed production; for instance, certain cultivars of French and yellow serradella occasionally flower at suboptimal times, potentially leading to reduced seed production. This study uncovered differences in how these cultivars produce flowers, pods and seeds. Some showed the ability to adapt to early flower loss, suggesting that selective breeding could improve seed yield resilience. [ABSTRACT FROM AUTHOR]

Context: Herbicide-resistant annual ryegrass (Lolium rigidum ; ARG) is a major weed of commercial significance globally, including no-till wheat-based production systems in south-eastern Australia. Aims: To compare the cost-effectiveness of different crop sequences and intensities of weed management to control ARG in rainfed grain production. Methods: Two on-farm studies in southern New South Wales, Australia, compared the effect of combinations of 3-year crop-sequence options (continuous wheat, 1- or 2-years of break crops), conservative or aggressive weed-control measures, hay cuts, legume brown manure (BM), and/or weed-free winter fallow on in-crop ARG infestations and soil seedbanks. Gross margins were calculated for each combination of treatments to compare system economic performance. Key results: Double-breaks consisting of two consecutive broadleaf crops, or canola–cereal hay, were frequently the most profitable and effective ARG control strategies. Single canola or lupin crops, BM, cereal hay, and fallow all significantly reduced subsequent in-crop ARG and seedbank numbers compared with continuous wheat. Aggressive in-crop control measures in wheat were more expensive than those applied to break crops. Gains in ARG control could be lost by a single year of poor weed control. Conclusions: High levels of control (>95%) over three consecutive seasons are required to reduce ARG seedbanks, and this is most cost-effectively achieved with diverse crop sequences. Implications: Farmers with high populations of ARG can reduce seedbanks by growing three crops sequentially that achieve complete weed seed control. This must be followed with ongoing high levels of control in subsequent years to keep ARG seedbanks low. The paper reports the outcomes of two on-farm experiments that aimed to identify the most cost-effective strategies to control herbicide-resistant annual ryegrass in rainfed, no-till, wheat-based farming systems in southern NSW. The studies linked efficacy of annual ryegrass control with the relative profitability of combinations of different crop sequences and agronomic management. The results showed that three consecutive years of >95% weed control by using diverse crops are required to cost-effectively reduce annual ryegrass seedbanks in soil to manageable levels. [ABSTRACT FROM AUTHOR]

Nitrogen (N) contributed by legumes is an important component of N supply to subsequent cereal crops, yet few Australian grain-growers routinely monitor soil mineral N before applying N fertiliser. Soil and crop N data from 16 dryland experiments conducted in eastern Australia from 1989-2016 were examined to explore the possibility of developing simple predictive relationships to assist farmer decision-making. In each experiment, legume crops were harvested for grain or brown-manured (BM, terminated before maturity with herbicide), and wheat, barley or canola were grown. Soil mineral N measured immediately before sowing wheat in the following year was significantly higher (P< 0.05) after 31 of the 33 legume pre-cropping treatments than adjacent non-legume controls. The average improvements in soil mineral N were greater for legume BM (60 [+ or -] 16kgN/ha; n = 5) than grain crops (35 [+ or -]20kgN/ha; n = 26), but soil N benefits were similar when expressed on the basis of summer fallow rainfall (0.15 [+ or -] 0.09 kg N/ha per mm), residual legume shoot dry matter (9 [+ or -] 5 kg N/ha per t/ha), or total legume residue N (28 [+ or -] 11%). Legume grain crops increased soil mineral N by 18 [+ or -] 9 kg N/ha per t/ha grain harvested. Apparent recovery of legume residue N by wheat averaged 30 [+ or -] 10% for 20 legume treatments in a subset of eight experiments. Apparent recovery of fertiliser N in the absence of legumes in two of these experiments was 64 [+ or -] 16% of the 51-75 kg fertiliser-N/ha supplied. The 25 year dataset provided new insights into the expected availability of soil mineral N after legumes and the relative value of legume N to a following wheat crop, which can guide farmer decisions regarding N fertiliser use. Additional keywords: canola, cereals, N uptake, pulses, rotation, sequence. Received 18 January 2017, accepted 20 June 2017, published online 13 July 2017, Introduction The concentrations of soil mineral (i.e. nitrate + ammonium) nitrogen (N) measured before sowing a cereal in dryland (rainfed) farming systems depends upon the relative balance between factors that [...]

Context: Opportunity exists to expand serradella (Ornithopus spp.) use onto heavier, duplex soil types in permanent pasture environments of south-eastern Australia. This requires cultivars with appropriate flowering times and flowering-date stability (i.e. flowering at the same date in spring regardless of timing of the autumn break). Aim: This work examined evidence of variation in flowering date and flowering-date stability in the NSW southern tablelands for a widely-used French serradella (O. sativus) cv. Margurita. Methods: Seed (sourced from a commercial supplier) was sown 21 March 2019 (Canberra, ACT) and 231 individual plants were monitored for time to first flower. A subset of plants exhibiting 'early' or 'late' flowering were identified and their seeds collected. In 2020, seed from ~15 plants from each selection was sown in Canberra in late March and early May to represent an 'early' and a 'later' break of season (n = 3). Key results: In the early-sown treatment, 'early-flowering' selections typically reached the median date of first flower (50%-flowering) from mid- to late August, while 'late-flowering' selections reached 50%-flowering early- to mid-September. When sown later, the 'early-flowering' selections began flowering from mid- to late September, while the 'late-flowering' selections flowered mid-September to early October. The 'early' selections exhibited greater flowering-date instability than 'late' selections and flowered particularly early when sown early. This indicated diversity within cv. Margurita for flowering-time control (e.g. vernalisation and/or photoperiod requirements). Implications: Evaluating cultivars of serradellas for flowering date and flowering date stability in their target environment(s) is essential to ensure cultivars are suitably adapted to these environments. Serradellas (Ornithopus spp.) are a novel legume option for the permanent pasture environments of south-eastern Australia. This paper investigated evidence of variation in flowering time characteristics within a widely used cultivar of French serradella. We recommend that new cultivars of serradellas be evaluated for flowering time characteristics in their target environment(s) to assess whether the cultivars are suitably adapted to these environments. This is essential to maximise production, feeding value and facilitate effective grazing management. [ABSTRACT FROM AUTHOR]