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Suboptimal distribution of photosynthetic capacity in relation to light among leaves reduces potential whole-canopy photosynthesis. We quantified the degree of suboptimality in 160 genotypes of wheat by directly measuring photosynthetic capacity and daily irradiance in flag and penultimate leaves. Capacity per unit daily irradiance was systematically lower in flag than penultimate leaves in most genotypes, but the ratio (γ) of capacity per unit irradiance between flag and penultimate leaves varied widely across genotypes, from less than 0.5 to over 1.2. Variation in γ was most strongly associated with differences in photosynthetic capacity in penultimate leaves, rather than with flag leaf photosynthesis or canopy light penetration. Preliminary genome-wide association analysis identified nine strong marker-trait associations with this trait, which should be validated in future work in other environments and/or materials. Our modelling suggests canopy photosynthesis could be increased by up to 5 % under sunny conditions by harnessing this variation through selective breeding for increased γ.

Crop photosynthesis and yield are limited by slow photosynthetic induction in sunflecks. We quantified variation in induction kinetics across diverse genotypes of wheat for the first time. Following a preliminary study that hinted at wide variation in induction kinetics across 58 genotypes, we grew 10 genotypes with contrasting responses in a controlled environment and quantified induction kinetics of carboxylation capacity (Vcmax) from dynamic A versus ci curves after a shift from low to high light (from 50 µmol m-2 s-1 to 1500 µmol m-2 s-1), in five flag leaves per genotype. Within-genotype median time for 95% induction (t95) of Vcmax varied 1.8-fold, from 5.2 min to 9.5 min. Our simulations suggest that non-instantaneous induction reduces daily net carbon gain by up to 15%, and that breeding to speed up Vcmax induction in the slowest of our 10 genotypes to match that in the fastest genotype could increase daily net carbon gain by up to 3.4%, particularly for leaves in mid-canopy positions (cumulative leaf area index ≤1.5 m2 m-2), those that experience predominantly short-duration sunflecks, and those with high photosynthetic capacities.

Faba bean is grown globally for human consumption and animal feed and is a significant rotation crop in cereal-dominant areas in many countries, including Australia. It is sensitive to several abiotic stresses, such as drought, frost, and high temperatures, especially at the reproductive stage. However, little is known of the upper and lower temperature limits for successful podding. Experiments were conducted over 2 years at Breeza and Narrabri in northwestern New South Wales to assess the impact of temperature on flowering and podset of three genotypes—Doza, Cairo, and IX1148f—under field conditions. Flowering nodes were tagged from designated plants in the field and scored for podding; field temperatures were recorded. Optimum maximum temperature for podset ranged from 23.7–26.1 °C, and the equivalent minimum temperature was 3.2–3.8 °C. Optimum average daily temperature for podset ranged from 12.7–13.9 °C. The strongest correlations between temperature and podding were observed at minimum temperatures, indicating that low temperatures are more important than high temperatures in determining yield in faba bean. [ABSTRACT FROM AUTHOR]

Bread wheat germplasm is accessed from the International Maize and Wheat Improvement Centre (CIMMYT) and the International Centre for Agricultural Research in the Dry Areas (ICARDA) by Australian wheat breeders and researchers through the CIMMYT Australia ICARDA Germplasm Evaluation (CAIGE) program. The CAIGE program coordinates the selection, importation, quarantine, dissemination, and evaluation of the imported bread wheat germplasm and the management of associated data and information. This paper describes the CAIGE model and assesses both the genetic and economic impacts of these materials on the Australian wheat industry after commercialisation of wheat breeding in the early 21st century and the establishment of CAIGE. The CAIGE concept was validated using data collected and analysed from multi-environment trials between 2017 and 2020. The impact of cultivars with and without CAIGE contribution to pedigree on yield was estimated using production-by-variety statistics. Net gain in yield, estimated as the yield difference between CAIGE and Non-CAIGE varieties, was multiplied by the percentage contribution to pedigree to estimate the additional yield. The CAIGE bread wheat program identified diverse, high-yielding, and disease-resistant germplasm and significantly improved the capture and dissemination of information. The benefit-cost ratio, calculated as the sum of benefits divided by investments, indicated that, for every dollar invested in CAIGE, a further $20 was generated in benefits. The internal rate of return was estimated at 163% and the modified rate at 18%. The benefits of these international materials to Australian wheat breeding remained significant. [ABSTRACT FROM AUTHOR]

High temperature stress affects tomato production both in tropical and sub-tropical environments worldwide. To explore genetic variation for heat tolerance in tomato, 329 transcontinental tomato genotypes were evaluated at the Ministry of Municipality and Environment (MME) greenhouses near Doha, Qatar, where the average daytime temperature was 38 °C with a big fluctuation during the tomato growth season. A preliminary phenotypic analysis identified a panel of 71 hybrid and pure-line tomato genotypes for more detailed studies. The selected subset was examined in the greenhouse using a randomized complete block design under heat stress. The materials were phenotyped for fruit size, fruit weight, fruit hardness, fruit locules, fruit set, total soluble solids (TSS), and fruit yield. Significant phenotypic differences among genotypes were observed for all the traits assessed. To explore the genetic basis of the variation among the examined genotypes, the subset was genotyped using 104 SNP markers identified in previous heat-tolerance genome-wide association studies (GWAS). Nineteen QTL-associated SNP markers could reliably select heat-tolerant genotypes in terms of better fruit yield, fruit set, and TSS. These markers are located on chromosome 1, 5, 6, 8, 9, and 12. Interestingly, two clusters of markers on chromosome 6 were linked to significant effects on yield, fruit set, and TSS under high temperature. Eighteen out of nineteen SNP markers were mapped within a gene body. Based on the phenotypic and the genotypic analysis, an elite set of five genotypes was selected for approval for heat stress environments in Qatar. The aim of the present work is to provide significant results that are exploitable not only in the Qatar region but also worldwide. Specifically, the 19 molecular markers identified in this study can serve as useful tools for breeders in selecting heat-tolerant material. [ABSTRACT FROM AUTHOR]

Hybrid breeding can increase the competitiveness of wheat (Triticum aestivum L.) in Sub-Saharan Africa by fostering more public-private partnerships and promoting investment by the private sector. The benefit of hybrid wheat cultivars in South Africa has previously been demonstrated but due to the high cost of hybrid seed production, hybrid breeding has not received significant attention in the past decade. Considering the renewed commitment of the private sector to establish wheat as a hybrid crop globally, coupled with significant research investment into enhancement of outcrossing of wheat, hybrid wheat breeding in Southern and Eastern Africa should be revisited. Our study aimed to identify genetically distinct germplasm groups in spring wheat that would be useful in the establishment of heterotic pools targeting this region. Multi-environment yield testing of a large panel of F1 test hybrids, generated using global elite germplasm, was carried out between 2019 and 2020 in Argentina, Africa, Europe, and Australia. We observed significant genotype by environment interactions within our testing network, confirming the distinctiveness of African trial sites. Relatively high additive genetic variance was observed highlighting the contribution of parental genotypes to the grain yield of test hybrids. We explored the genetic architecture of these parents and the genetic factors underlying the value of parents appear to be associated with their genetic subgroup, with positive marker effects distributed throughout the genome. In testcrosses, elite germplasm from the International Maize and Wheat Improvement Center (CIMMYT) appear to be complementary to the genetically distinct germplasm bred in South Africa. The feasibility of achieving genetic gain via heterotic pool establishment and divergence, and by extension the viability of hybrid cultivars in Sub-Saharan Africa, is supported by the results of our study. [ABSTRACT FROM AUTHOR]

Introduction: In plant breeding, we often aim to improve multiple traits at once. However, without knowing the economic value of each trait, it is hard to decide which traits to focus on. This is where "desired gain selection indices" come in handy, which can yield optimal gains in each trait based on the breeder's prioritisation of desired improvements when economic weights are not available. However, they lack the ability to maximise the selection response and determine the correlation between the index and net genetic merit. Methods: Here, we report the development of an iterative desired gain selection index method that optimises the sampling of the desired gain values to achieve a targeted or a user-specified selection response for multiple traits. This targeted selection response can be constrained or unconstrained for either a subset or all the studied traits. Results: We tested the method using genomic estimated breeding values (GEBVs) for seven traits in a bread wheat (Triticum aestivum) reference breeding population comprising 3,331 lines and achieved prediction accuracies ranging between 0.29 and 0.47 across the seven traits. The indices were validated using 3,005 double haploid lines that were derived from crosses between parents selected from the reference population. We tested three user-specified response scenarios: a constrained equal weight (INDEX1), a constrained yield dominant weight (INDEX2), and an unconstrained weight (INDEX3). Our method achieved an equivalent response to the user-specified selection response when constraining a set of traits, and this response was much better than the response of the traditional desired gain selection indices method without iteration. Interestingly, when using unconstrained weight, our iterative method maximised the selection response and shifted the average GEBVs of the selection candidates towards the desired direction. Discussion: Our results show that the method is an optimal choice not only when economic weights are unavailable, but also when constraining the selection response is an unfavourable option. [ABSTRACT FROM AUTHOR]

Cereal rye and its wild forms are important sources of genetic diversity for wheat breeding due to their resistances to biotic and abiotic stresses. Secale strictum subsp. anatolicum (Boiss.) K. Hammer (SSA) is a weedy relative of cultivated rye, S. cereale. Meiotic chromosome pairing in [F.sub.1] hybrids of SSA and S. cereale reveals strong genomic affinity between the two genomes. A study of the transferability of S. cereale sequencebased markers to SSA and hexaploid triticale demonstrated their applicability for tracing SSA chromatin in wheat. The transferability of the markers was over 80% from homoeologous groups 1, 2, and 3, and greater than 70% from groups 4 to 7. This study focused on the generation and molecular and cytogenetic characterization of wheat-SSA alien derivatives. Twelve were identified using combinations of non-denaturing fluorescence in situ hybridization (ND-FISH), genomic in situ hybridization (GISH), and molecular marker analysis. All SSA chromosomes, except 3R (a) and 6R (a), were transferred to wheat either in the form of monosomic additions (MA), mono-telosomic additions (MtA), double-mono-telosomic additions (dMtA), or double-monosomic additions (dMA). The germplasm developed in this study will help to enhance the genetic base of wheat and facilitate molecular breeding of wheat and triticale. Key words: Secale strictum subsp. anatolicum, bread wheat, in situ hybridization, PCR markers, genome affinity. Le seigle cultive et ses formes sauvages constituent d'importantes sources de diversite genetique pour l'amelioration genetique du ble en raison de leur resistance a des stress biotiques et abiotiques. Le Secale strictum subsp. anatolicum (Boiss.) K. Hammer (SSA) est une adventice apparentee au seigle cultive, S. cereale. L'appariement meiotique des chromosomes chez des hybrides [F.sub.1] entreleSSA et S. cereale revele la forte affinite entre ces deux genomes. Une etude de la transportabilite de marqueurs moleculaires du S. cereale vers le SSA et le triticale hexaploide montre leur utilite pour suivre la trace de la chromatine du SSA chez le ble. La transportabilite de ces marqueurs excedait 80 % chez les homeologues des groupes 1, 2 et 3, et il depassait 70 % chez ceux des groupes 4 a 7. Cette etude a porte sur la production et la caracterisation moleculaire et cytogenetique de lignees derivees de croisements ble-SSA. Douzedeceslignees ont eteidentifiees en employant une combinaison de diverses techniques : l'hybridation in situ en fluorescence sans denaturation (ND-FISH), l'hybridation genomique in situ (GISH) et l'analyse de marqueurs moleculaires. Tous les chromosomes du SSA, a l'exception de 3R (a) et 6R (a), ont ete introduits chez le ble soit sous la forme d'additions monosomiques (MA), mono-telosomiques (MtA), doubles mono-telosomiques (dMtA) ou doubles monosomiques (dMA). Les ressources genetiques developpees au cours de ce travail permettront d'enrichir l'assise genetique du ble et de faciliter l'amelioration moleculaire chez le ble et le triticale. [Traduit par la Redaction] Mots-cles : Secale strictum subsp. anatolicum, ble tendre, hybridation in situ, marqueurs PCR, affinite des genomes., Introduction Secale L. is an important genus in the tertiary gene pool for wheat improvement, including cultivated cereal rye (S. cereale L.) and many wild, weedy, and feral species (Chikmawati [...]

Sequence-based markers have added a new dimension in the efficiency of identifying alien introgressions in wheat. Expressed sequence tag-sequence tagged sites (EST-STS) markers have proved useful in tracing alien chromatin. In this study, we report the development of Thinopyrum bessarabicum- and Secale anatolicum-specific EST-STS markers and their application in tracing respective alien chromatin introgressions in wheat. The parental lines, Chinese Spring (CS), ISR991.1 (CS/Th. bessarabicum amphidiploid), and ISR1049.2 (CS/Secale anatolicum amphidiploid), were used as core experimental materials. Using comparative analysis of RNA-Seq data, 10 903 and 10 660 candidate sequences specific to Th. bessarabicum and S. anatolicum, respectively, were assembled and identified. To validate the genome specificity of these candidate sequences, 68 and 64 EST-STS markers were developed from randomly selected candidate sequences of Th. bessarabicum and S. anatolicum, respectively, and tested on sets of alien addition lines. Fifty-five and 53 markers for Th. bessarabicum and S. anatolicum chromatin, respectively, were assigned to chromosomal location(s), covering all seven chromosomes. Approximately 83% of S. anatolicum-specific markers were transferable to S. cereale. The genome-specific candidate sequences identified and the EST-STS markers developed will be valuable resources for exploitation of Th. bessarabicum and Secale species diversity in wheat and triticale breeding. Key words: RNA sequencing, expressed sequence tags, sequence tagged sites, Thinopyrum bessarabicum, Secale anatolicum, EST-STS markers. Les marqueurs fondes sur la sequence d'ADN ont rendu plus efficace l'identification d'introgressions interspecifiques d'ADN chez le ble. Les marqueurs EST-STS ('expressed sequence tag-sequence tagged sites') se sont averes tres puissants pour identifier la chromatine etrangere. Dans cette etude, les auteurs rapportent le developpement de marqueurs EST-STS specifiques pour le Thinopyrum bessarabicum et le Secale anatolicum ainsi que leur utilisation pour suivre les introgressions respectives de chromatine chez le ble. Les lignees parentales, Chinese Spring (CS), ISR991.1 (amphiploide CS/Th. bessarabicum) et ISR1049.2 (amphiploide CS/S. anatolicum), ont ete employees comme materiel experimental. Au moyen d'une analyse comparee de donnees RNA-Seq, 10 903 et 10 660 sequences candidates specifiques du Th. bessarabicum et du S. anatolicum ont ete assemblees et identifiees. Pour valider la specificite genomique de ces sequences, 68 et 64 marqueurs EST-STS, respectivement, ont ete mis au point a partir de sequences candidates du Th. bessarabicum et du S. anatolicum choisies aleatoirement. Ces marqueurs ont ensuite ete testes sur des lignees d'addition. Cinquante-cinq et 53 marqueurs du Th. bessarabicum et du S. anatolicum, respectivement, se sont vu assigner une position chromosomique, et ces marqueurs couvraient l'ensemble des sept chromosomes. Environ 83% des marqueurs specifiques de la chromatine du S. anatolicum ont ete transferes avec succes chez le S. cereale. Les sequences candidates specifiques du genome identifiees ainsi, de meme que les marqueurs EST-STS qui en decoulaient seront des ressources utiles pour l'exploitation de la diversite disponible chez le Th. bessarabicum et le S. anatolicum en amelioration genetique du ble et du triticale. [Traduit par la Redaction] Mots-cles : sequencage de l'ARN, etiquettes de sequences exprimees, sites nucleotidiques polymorphes, Thinopyrum bessarbicum, Secale anatolicum, marqueurs EST-STS., Introduction Transcriptome sequencing, or RNA sequencing (RNA-Seq), has offered a valuable and cost-effective approach in deciphering numerous genomic features in a single high throughput experiment. Transcriptome analyses are being used [...]

Forty wheat samples of ten wheat varieties harvested from optimal or late sowings in 2019 and 2020 were evaluated for nutrient composition. This included crude protein (CP), starch, amino acids, minerals, phytate-phosphorus (phytate-P) and non-starch polysaccharides (NSPs). The objective was to investigate the impact of high temperature on wheat grain quality as a feedstuff for broiler chickens. Growth performance and economic impact of such changes were predicted by the Emmans, Fisher and Gous broiler growth model. On average, 2019 was 1 °C hotter than 2020 during the growing season (Narrabri, NSW 2390, Australia). The wheat harvested in 2019 had higher concentrations of CP, phytate-P, total P and calcium. In 2019, late sowing increased average protein concentrations from 166.6 to 190.2 g/kg, decreased starch concentration from 726 to 708 g/kg and increased total NSPs from 693 to 73.9 g/kg. Unlike the 2019 harvest, the late sowing in 2020 had no impact on CP concentrations in almost all wheat varieties. The 2019 varieties had higher concentrations of 16 assessed amino acids (p < 0.001) compared to the 2020 harvest. The largest difference was in lysine (19.2%), and the smallest difference was in proline (11.1%). It was predicted that broiler diets formulated from 2019 wheat varieties would have better efficiency of feed conversion with an advantage of 2.53% (1.539 versus 1.579) than 2020 varieties to 35 days post-hatch. This would translate to a cost saving of approximately AUD 16.45 per tonne of feed, much of which would represent additional profit. [ABSTRACT FROM AUTHOR]