Characterizing prediction errors of a new tree height model for cut-to-length Pinus radiata stems through the Burr TypeⅫdistribution

Unlike height-diameter equations for standing trees commonly used in forest resources modelling,tree height models for cut-to-length(CTL)stems tend to produce prediction errors whose distributions are not conditionally normal but are rather leptokurtic and heavy-tailed.This feature was merely noticed in previous studies but never thoroughly investigated.This study characterized the prediction error distribution of a newly developed such tree height model for Pin us radiata(D.Don)through the three-parameter Burr TypeⅫ(BⅫ)distribution.The model’s prediction errors(ε)exhibited heteroskedasticity conditional mainly on the small end relative diameter of the top log and also on DBH to a minor extent.Structured serial correlations were also present in the data.A total of 14 candidate weighting functions were compared to select the best two for weightingεin order to reduce its conditional heteroskedasticity.The weighted prediction errors(εw)were shifted by a constant to the positive range supported by the BXII distribution.Then the distribution of weighted and shifted prediction errors(εw+)was characterized by the BⅫdistribution using maximum likelihood estimation through 1000 times of repeated random sampling,fitting and goodness-of-fit testing,each time by randomly taking only one observation from each tree to circumvent the potential adverse impact of serial correlation in the data on parameter estimation and inferences.The nonparametric two sample Kolmogorov-Smirnov(KS)goodness-of-fit test and its closely related Kuiper’s(KU)test showed the fitted BⅫdistributions provided a good fit to the highly leptokurtic and heavy-tailed distribution ofε.Random samples generated from the fitted BⅫdistributions ofεw+derived from using the best two weighting functions,when back-shifted and unweighted,exhibited distributions that were,in about97 and 95%of the 1000 cases respectively,not statistically different from the distribution ofε.Our results for cut-tolength P.radiata stems represented the first case of any tree species where a non-normal error distribution in tree height prediction was described by an underlying probability distribution.The fitted BXII prediction error distribution will help to unlock the full potential of the new tree height model in forest resources modelling of P.radiata plantations,particularly when uncertainty assessments,statistical inferences and error propagations are needed in research and practical applications through harvester data analytics.

A gene expression estimator of intramuscular fat percentage for use in both cattle and sheep

Background:The expression of genes encoding proteins involved in triacyglyceride and fatty acid synthesis and storage in cattle muscle are correlated with intramuscular fat(IMF)%.Are the same genes also correlated with IMF%in sheep muscle,and can the same set of genes be used to estimate IMF%in both species?Results:The correlation between gene expression(microarray) and IMF%in the longissimus muscle(LM) of twenty sheep was calculated.An integrated analysis of this dataset with an equivalent cattle correlation dataset and a cattle differential expression dataset was undertaken.A total of 30 genes were identified to be strongly correlated with IMF%in both cattle and sheep.The overlap of genes was highly significant,8 of the 13 genes in the TAG gene set and 8 of the 13 genes in the FA gene set were in the top 100 and 500 genes respertively most correlated with IMF%in sheep,P-value = 0.Of the 30 genes,CIDEA,THRSP,ACSM1,DGAT2 and FABP4 had the highest average rank in both species.Using the data from two small groups of Brahman cattle(control and Hormone growth promotant-treated[known to decrease IMF%in muscle]) and 22 animals in total,the utility of a direct measure and different estimators of IMF%(ultrasound and gene expression) to differentiate between the two groups were examined.Directly measured IMF%and IMF%estimated from ultrasound scanning could not discriminate between the two groups.However,using gene expression to estimate IMF%discriminated between the two groups.Increasing the number of genes used to estimate IMF%from one to five significantly increased the discrimination power;but increasing the number of genes to 15 resulted in little further improvement.Conclusion:We have demonstrated the utility of a comparative approach to identify robust estimators of IMF%in the LM in cattle and sheep.We have also demonstrated a number of approaches(potentially applicable to much smaller groups of animals than conventional methods) to using gene expression to rank animals for IMF%within a single farm/treatment,or to estimate differences in IMF%between two farms/treatments.

Characterisation of pH decline and meat color development of beef carcasses during the early postmortem period in a Chinese beef cattle abattoir

This study investigated the pH/temperature decline of beef carcasses in a typical Chinese abattoir and color development as pH declined during rigor onset. A natural cubic spline model was used to model the pH/temperature decline for those carcasses which passed through pH 6.0. Six of the 97 carcasses that exhibited a high(≥6.10) ultimate pH(pHu)(darkcutting) in the M. longissimus lumborum(LL) were sampled, along with the same numbers of normal pHu and intermediate pHu carcasses(5.40–5.79; 5.80–6.10, respectively), to examine color development within 24h postmortem. It was shown that 66.7% of the modeled carcasses were outside the ideal pH/temperature window with a temperature@pH6.0 lower than ideal, suggesting the need for acceleration of the pH decline. The stable and low a~*, b~* and chroma values of high pHu beef within the first 12h indicated dark-cutting beef might be detected earlier than expected.

Implications of step-chilling on meat color investigated using proteome analysis of the sarcoplasmic protein fraction of beef longissimus lumborum muscle

In order to improve beef color and color stability,step-chilling(SC)was applied on excised bovine longissimus lumborum muscle,with chilling starting at 0–4℃ for 5 h,then holding the temperature at 12–18℃ for 6 h,followed by 0–4℃ again until 24 h post-mortem.pH and temperature were measured during rigor on SC loins as well as those subjected to routine chilling(RC,0–4℃,till 24 h post-mortem).Color L*,a*,b*values,metmyoglobin(MetM b)content,MetM b reducing ability(MRA)and NADH content were determined on samples aged for 1,7,and 14 d.Sarcoplasmic proteome analysis was only conducted on d 1 samples.The results showed muscles subjected to SC maintained a temperature at around 15℃ for 5 to 10 h post-mortem,and exhibited a slow temperature decline,but rapid pH decline.Beef steaks treated with SC had higher L*,a*,b* and chroma values than those of RC samples at 1 and 7 d chilled storage(0–4℃),while showing no significant difference for a*,b* and chroma values at d 14.The SC samples also exhibited a lower relative content of surface MetM b,higher MRA and NADH content,compared with RC beef steaks during storage,indicating the SC-treated beef showed an improved color stability.Eleven differential protein spots/nine proteins were identified by two-dimensional gel electrophoresis and mass spectrometry,and those proteins were mainly involved in redox,chaperone binding,metabolic and peroxidase activity.Oxidoreductases play a role in decreasing the oxidation-induced myoglobin oxidation and benefiting the production of NADH,and finally improving the colour of beef.Of these,pyruvate dehydrogenase E1 component subunit beta showed a positive correlation with color L*,a*,b*values and accounted for more than 60% of the variation in color values;this protein can be considered as a potential beef color biomarker.The present study provided valuable information for studies on the molecular mechanism of color improvement from step-chilling,as well as for identifying markers associated with beef color.

Effect of stripe rust on the yield response of wheat to nitrogen

Nitrogen(N) is the most important fertiliser element determining the productivity of wheat.N nutrition is known to affect the level of stripe rust infection, with higher N associated with increased disease severity. Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a major yield-limiting disease of wheat in Australia. This paper describes experiments designed to investigate the agronomic response to the interaction of various levels of N application and stripe rust severity in wheat varieties differing in response. Experimental plots were established in crop seasons 2006 and 2007 on the Liverpool Plains of northern NSW, Australia.Yield, biomass, grain protein content(GPC) and harvest index(HI) data were recorded.Increased rates of N increased the severity of stripe rust during grain filling. N application also increased yield and GPC in all varieties in both years. Stripe rust reduced the yield of the rust-susceptible wheat varieties, and GPC and proportion of added N recovered in the grain were also reduced in one year but not the other. It was evident from our experiment that stripe rust caused yield loss accompanied by either no change or reduction in GPC, indicating that the total amount of N entering the grain was reduced by stripe rust. The effects of stripe rust on N yield are most likely associated with reduced uptake of N during grain filling.

Characteristics of canopy interception and its simulation with a revised Gash model for a larch plantation in the Liupan Mountains, China

Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.(larch) plantation in the Liupan Mountains of northwestern China during the growing season(May–October) of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss(79%) mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model's ability in simulating the interception of individual rainfall events were suggested.

De novo design of future rapeseed crops:Challenges and opportunities

To address the global demand for rapeseed while considering farmers’profit,we face the challenges of making a quantum leap in seed yield and,at the same time,reducing yield loss due to biotic and abiotic stresses.We also face the challenge of efficiently applying new transformative biotechnology tools such as gene editing and breeding by genome design to increase rapeseed productivity and profitability.In this Perspective,we review advances in research on the physiological and genetic bases of both stress factorsaffected yield stability and seed yield potential,focusing on source–sink relationships and allocation of photosynthetic assimilates to vegetative growth and seed development.We propose research directions and highlight the role of plant architecture in the relative contributions of the root system,leaves,and pods to seed yield.We call for de novo design of new rapeseed crops.We review trait variation in existing germplasm and biotechnologies available for crop design.Finally,we discuss opportunities to apply fundamental knowledge and key germplasm to rapeseed production and propose an ideotype for de novo design of future rapeseed cultivars.

Phylogenetic and morphological significance of an overlooked flying squirrel(Pteromyini,Rodentia)from the eastern Himalayas with the description of a new genus

The flying squirrels(Pteromyini,Rodentia)are the most diverse and widely distributed group of gliding mammals.Taxonomic boundaries and relationships within flying squirrels remain an area of active research in mammalogy.The discovery of new specimens of Pteromys(Hylopetes)leonardi Thomas,1921,previously considered a synonym of Hylopetes alboniger,in Yunnan Province,China allowed a morphological and genetic reassessment of the status of this taxon.Phylogenetic reconstruction was implemented using sequences of two mitochondrial(12S ribosomal RNA and 16S ribosomal RNA)and one nuclear(interphotoreceptor retinoid-binding protein)gene fragments.Morphological assessments involved examinations of features preserved on skins,skulls,and penises of museum specimens,supplemented with principal component analysis of craniometric data.Together these assessments revealed that this taxon should be recognized not only as a distinct species,but should also be placed within a new genus,described here as Priapomys gen.nov.

The current status of nitrogen fertiliser use efficiency and future research directions for the Australian cotton industry

Fifty years of sustained investment in research and development has left the Australian cotton industry well placed to manage nitrogen(N) fertiliser. The average production in the Australian cotton industry today is greater than two tonnes of lint per hectare due to improved plant genetics and crop management. However, this average yield is well below the yield that would be expected from the amount of N fertiliser used. It is clear from the recent studies that across all growing regions, conversion of fertiliser N into lint is not uniformly occurring at application rates greater than 200-240 kg·hm^(-2) of N. This indicates that factors other than N availability are limiting yield, and that the observed nitrogen fertiliser use efficiency(NFUE) values may be caused by subsoil constraints such as sodicity and compaction. There is a need to investigate the impact of subsoil constraints on yield and NFUE.Gains in NFUE will be made through improved N fertiliser application timing, better targeting the amount of fertiliser applied for the expected yield, and improved soil N management. There is also a need to improve the ability and confidence of growers to estimate the contribution of soil N mineralisation to the crop N budget. Many Australian studies including data that could theoretically be collated in a meta-analysis suggest relative NFUE values as a function of irrigation technique; however, with the extensive list of uncontrolled variables and few studies using non-furrow irrigation, this would be a poor substitute for a single field-based study directly measuring their efficacies. In irrigated cotton, a re-examination of optimal NFUE is due because of the availability of new varieties and the potential management and long-term soil resilience implications of the continued removal of mineralised soil N suggested by high NFUE values. NFUE critical limits still need to be derived for dryland systems.

Comparative performances of new and existing indices of crown asymmetry:an evaluation using tall trees of Eucalyptus pilularis(Smith)

Over the past 50 years,crown asymmetry of forest trees has been evaluated through several indices constructed from the perspective of projected crown shape or displacement but often on an ad hoc basis to address specifi c objectives related to tree growth and competition,stand dynamics,stem form,crown structure and treefall risks.Although sharing some similarities,these indices are largely incoherent and non-comparable as they diff er not only in the scale but also in the direction of their values in indicating the degree of crown asymmetry.As the fi rst attempt at devising normative measures of crown asymmetry,we adopted a relative scale between 0 for perfect symmetry and 1 for extreme asymmetry.Five existing crown asymmetry indices(CAIs)were brought onto this relative scale after necessary modifi cations.Eight new CAIs were adapted from measures of circularity for digital images in computer graphics,indices of income inequality in economics,and a bilateral symmetry indicator in plant leaf morphology.The performances of the 13 CAIs were compared over diff erent numbers of measured crown radii for 30 projected crowns of mature Eucalyptus pilularis trees through benchmarking statistics and rank order correlation analysis.For each CAI,the index value based on the full measurement of 36 evenly spaced radii of a projected crown was taken as the true value in the benchmarking process.The index(CAI 13)adapted from the simple bilateral symmetry measure proved to be the least biased and most precise.Its performance was closely followed by that of three other CAIs.The minimum number of crown radii that is needed to provide at least an indicative measure of crown asymmetry is four.For more accurate and consistent measures,at least 6 or 8 crown radii are needed.The range of variability in crown morphology of the trees under investigation also needs to be taken into consideration.Although the CAIs are from projected crown radii,they can be readily extended to individual tree crown metrics that are now commonly extracted from LiDAR and other remotely sensed data.Adding a normative measure of crown asymmetry to individual tree crown metrics will facilitate the process of big data analytics and artifi cial intelligence in forestry wherever crown morphology is among the factors to be considered for decision making in forest management.

Extraction of Flavonoids from Bitter Melon

Bitter melon, Momordica charantia L, is a popular traditional medicinal fruit in tropical and subtropical countries. It has been linked with therapeutic effects, some of which are likely due to its flavonoids. To determine its total flavonoid content (TFC) and to prepare extracts for use as nutritional supplements or ingredients for nutraceutical functional foods, various solvents have been used, including water, which is the preferred solvent because it is inexpensive, safe and environmentally friendly. The study aimed to extract bitter melon, using five solvents (ethanol, methanol, n-butanol, acetone and water) before and after the optimal conditions for water were determined in terms of extraction temperature, time, ratio of water to bitter melon (mL/g) and number of times the same material was extracted. The TFC of six varieties of bitter melon was also determined. Acetone was the best of the five solvents for extracting flavonoids from the Moonlight variety (23.2 mg Rutin Equivalents (RE)/g). Even after increasing the extraction by 88% (1.24 vs 0.66 mg RE/g) using optimised conditions for the aqueous extraction (two extractions at 40℃ for 15 min at a ratio of 100:1 mL/g of bitter melon powder), the flavonoids extracted from the Moonlight variety using water was very little (5.4%) compared to acetone. Furthermore, using acetone, it was shown that the Moonlight variety (23.2 mg RE/g) bought at a local market had higher levels of flavonoids than the greenhouse-grown Jade (15.3 mg RE/g), Niddhi (16.9 mg RE/g), Indra (15.0 mg RE/ g), Hanuman (3.9 mg RE/g) and White (6.9 mg RE/g) varieties. Therefore, acetone was the best solvent for extracting flavonoids from bitter melon and the aqueous extraction could only be improved to extract 5.4% of the flavonoids extracted with acetone from the Moonlight variety, which had the highest TFC of the six varieties of bitter melon.

Developments in Fractionation and Measurement of Soil Organic Carbon: A Review

Soil organic carbon (SOC) is the percentage measure of carbon (C) derived from living organisms in soil. Stability of soil organic matter (SOM) can be defined in terms of how easily C and nitrogen in the SOM can be decomposed. Due to the implications in the permanence of SOC during sequestration there is scientific interest in fractionation of SOM into different fractions. A large number of SOM fractionation procedures have been developed to distinguish between SOM to study whether it is liable or recalcitrant to activities of soil microbes. There are physical and chemical fractionation techniques. The former is based on particle size and density of soil samples or combination of the two, and the latter on the reaction of chemical on SOM for the separation of stable SOC. Each fraction of SOC in the laboratory can be commonly determined using wet oxidation by Walkley-Black method and dry combustion by LECO CN Analyzer. With the advancement in chemometric statistical techniques;faster, robust, cheaper and non-destructive methods are emerging. The chemometric statistical techniques do not require any reagents for analysis compared with the wet oxidation or dry combustion methods. Thus, these emerging techniques are highly attractive for studies where a large number of analyses are required. For in situ measurement of SOC, spectral reflectance technology is developed to facilitate instant measurement in the field using the sensors or by remote sensing.

Protein profiles of enzymatically isolated rumen epithelium in sheep fed a fibrous diet

Background: The rumen wall plays a major role in efficient transfer of digested nutrients in the rumen to peripheral tissues through the portal venous system. Some of these substrates are metabolised in the epithelium during this process. To identify the specific proteins involved in these processes, we used proteomic technologies. Protein extracts were prepared from ventral rumen tissue of six sheep fed a fibrous diet at 1.5× maintenance energy requirements.Using a newly developed method, we were able to enzymatically isolate the epithelial cells from underlying tissue layers, thus allowing cytosol and membrane fractions to be independently analysed using liquid chromatography tandem mass spectrometry(LC MS/MS).Results: Using our procedure we identified 570 epithelial proteins in the Ovis aries sequence database. Subcellular locations were largely cytosolic(n = 221) and extracellular(n = 85). However, a quarter of the proteins identified were assigned to the plasma membrane or organelle membranes, some of which transport nutrients and metabolites. Of these 91 were transmembrane proteins(TMHMM), 27 had an N-terminal signal peptide(signalP) and TMHMM motif,13 had a glycosylphosphatidylinositol(GPI) anchor and signalP sequence, 67 had beta(β) strands or 17 β strands and a transit peptide sequence, indicating the identified proteins were integral or peripheral membrane proteins. Subunits of the 5 protein complexes involved in mitochondrial cellular energy production were well represented. Structural proteins(15%), proteins involved in the metabolism of lipids and proteins(26%) and those with steroid or cytokine action were a feature of the proteome.Conclusion: Our research has developed a procedure to isolate rumen epithelium proteins from the underlying tissue layers so that they may be profiled using proteomic technologies. The approach improves the number of proteins that can be profiled that are specific to the epithelium of the rumen wall. It provides new insights into the proteins of structural and nutritional importance in the rumen epithelium, that carry out nutrient transport and metabolism, cell growth and signalling.

Additive predictions of aboveground stand biomass in commercial logs and harvest residues for rotation age Pinus radiata plantations in New South Wales,Australia

Two systems of additive equations were developed to predict aboveground stand level biomass in log products and harvest residue from routinely measured or predicted stand variables for Pinus radiata plantations in New South Wales,Australia.These plantations were managed under three thinning regimes or stand types before clear-felling at rotation age by cut-to-length harvesters to produce sawlogs and pulpwood.The residue material following a clear-fell operation mainly consisted of stumps,branches and treetops,short off-cut and waste sections due to stem deformity,defects,damage and breakage.One system of equations did not include dummy variables for stand types in the model specification and was intended for more general use in plantations where stand density management regimes were not the same as the stand types in our study.The other system that incorporated dummy variables was for stand type-specific applications.Both systems of equations were estimated using 61 plot-based estimates of biomass in commercial logs and residue components that were derived from systems of equations developed in situ for predicting the product and residue biomass of individual trees.To cater for all practical applications,two sets of parameters were estimated for each system of equations for predicting component and total aboveground stand biomass in fresh and dry weight respectively.The two sets of parameters for the system of equations without dummy variables were jointly estimated to improve statistical efficiency in parameter estimation.The predictive performances of the two systems of equations were benchmarked through a leave-one-plot-out cross validation procedure.They were generally superior to the performance of an alternative two-stage approach that combined an additive system for major components with an allocative system for sub-components.As using forest harvest residue biomass for bioenergy has increasingly become an integrated part of forestry,reliable estimates of product and residue biomass will assist harvest and management planning for clear-fell operations that integrate cut-to-length log production with residue harvesting.

Acid Sulfate Soil Induced Acidification of Estuarine Areas Used for the Production of Sydney Rock Oysters, <i>Saccostrea glomerata</i>

This study investigated estuarine acidification, associated with drainage and excavation of acid sulfate soils, in areas used for commercial cultivation of Sydneyrock oysters (Saccostrea glomerata). Regular measurements of pH and electrical conductivity were collected in oyster cultivation areas and acidified reaches of the Hastings River estuary and Port Stephens estuary located on the mid north coast of New South Wales, Australia. Water quality information from acidified floodplain drains was also collected in theHastingsRiverfollowing heavy rainfall. Both estuaries experienced acidification of tributaries following periods of heavy rainfall. Drain outflow waters were acidic

Corrigendum to“De novo design of future rapeseed crops:Challenges and opportunities”[Crop J.10(2022)587-596]

The authors regret to report some mistakes in the text and associated changes necessary to section 4.1 of the paper.On page 591 in the right-hand column,line 34,“far light”should be changed to“far-red light”.On page 592 in the left-hand column,line 28,the sentence reads:“If the YP/FP ratio can be as high as 42%(the average YP/FP of the UK and China.Table S2),the farm yield will be 5.0 t ha1.”

Localisation of Loci Involved in Resistance to <i>Diaporthe toxica</i>and <i>Pleiochaeta setosa</i>in White Lupin (<i>Lupinus albus</i>L.)

L. albus is an annual grain-legume crop mainly grown for high-protein fodder worldwide but also to produce large seeds for human consumption as a snack-food. In order to make genetic gains in grain yield, assessment of the genetic variation in the germplasm and identification of loci associated with agronomic traits are essential. Phomopsis blight (PB) and Pleiochaeta root rot (PRR), caused by the fungal pathogens Diaporthe toxica and, Pleiochaeta setosa respectively, are two major yield-limiting diseases of the L. albus crop. The extent of genetic diversity in 94 accessions of L. albus comprising: Australian and exotic cultivars, advanced breeding lines, and landraces originating from 26 different countries was determined utilizing PCR-based genic, and microarray-based Diversity Arrays Technology (DArT&#8482), markers. All accessions were evaluated for resistance to PB in two plant tissues (leaves and stems) using either sprayed or injected spore inoculum. A subset of 58 accessions was further evaluated for resistance to PRR by growing seedlings in spore-infested potting mix. The combined data of 724 (50 genic- and 674 DArT) markers were used for cluster analysis. A subset of 324 markers with call rate ≥95% and predicted disease scores of different genotypes were used to identify marker loci accounting for phenotypic variation in PB and PRR resistance using linear regression analysis. Several markers showed significant association with PB or PRR resistance at P < 0.05. Our results showed that favourable alleles for PB and PRR resistance are present in the diverse accessions investigated and they will provide valuable materials for lupin breeding.

Analyses Using SSR and DArT Molecular Markers Reveal that Ethiopian Accessions of White Lupin (<i>Lupinus albus</i>L.) Represent a Unique Genepool

PCR-based genic and microarray-based Diversity Arrays Technology (DArTTM) markers were used to determine genetic diversity in 94 accessions of white lupin (Lupinus albus L.) comprising Australian and foreign cultivars, landraces, and advanced breeding lines from Australian breeding programs. A total of 345 (50 PCR-based and 295 DArT-based) polymorphic fragments were identified, which were used to determine the genetic diversity among accessions. Both cluster analysis of bivariate marker data using UPGMA, and principal coordinate analysis, indicated a high level of genetic diversity in the germplasm. Our results showed that both types of markers used in this study are suitable for estimation of genetic diversity. Landrace accessions from Ethiopia formed a very distinct and separate grouping with both marker systems. Australian cultivars and breeding lines were clustered together and tended to be distinct from European landraces. These findings will allow breeders to select appropriate, diverse parents to broaden the genetic base of white lupin breeding populations.

Validation of Competitive Ability of Diverse Canola Accessions against Annual Ryegrass under Glasshouse and Field Conditions

Weeds are a major constraint in canola (Brassica napus L.) production worldwide, as they cause significant reductions in seed yield and quality. Crop interference is one of the approaches to tackle weed infestation along with other agronomic interventions. In Australia, studies have shown genetic variation in the canola capability to suppress annual ryegrass (Lolium rigidum Gaudin) in the field and under in vitro conditions. Early-season crop biomass accumulation and greater plant height are desired attributes for suppression weeds in canola. However, the canola ideotype for interference traits against this weed has not been studied under glasshouse conditions. In this study, we compared the competitive ability of 26 canola genotypes against annual ryegrass under both glasshouse and field conditions. Five canola genotypes consistently showed the ability to suppress growth of annual ryegrass. Both at glasshouse and field conditions, the shoot biomass, largely contributed by leaf biomass, was significantly associated with suppression ability. Our results suggest that a glasshouse-based evaluation approach can be used to determine the suppressive ability of advanced breeding lines for suppression of ryegrass growth. Based on our analysis, we suggest that initial screening of large collections of germplasm can be conducted under glasshouse conditions, with selected genotypes further evaluated in the field.