Modern Cultivars Research Articles

Transcriptome-based variations effectively untangling the intraspecific relationships and selection signals in Xinyang Maojian tea population.

As one of the world's top three popular non-alcoholic beverages, tea is economically and culturally valuable. Xinyang Maojian, this elegant green tea, is one of the top ten famous tea in China and has gained prominence for thousands of years. However, the cultivation history of Xinyang Maojian tea population and selection signals of differentiation from the other major variety Camellia sinensis var. assamica (CSA) remain unclear. We newly generated 94 Camellia sinensis (C. sinensis) transcriptomes including 59 samples in the Xinyang area and 35 samples collected from 13 other major tea planting provinces in China. Comparing the very low resolution of phylogeny inferred from 1785 low-copy nuclear genes with 94C. sinensis samples, we successfully resolved the phylogeny of C. sinensis samples by 99,115 high-quality SNPs from the coding region. The sources of tea planted in the Xinyang area were extensive and complex. Specifically, Shihe District and Gushi County were the two earliest tea planting areas in Xinyang, reflecting a long history of tea planting. Furthermore, we identified numerous selection sweeps during the differentiation of CSA and CSS and these positive selection genes are involved in many aspects such as regulation of secondary metabolites synthesis, amino acid metabolism, photosynthesis, etc. Numerous specific selective sweeps of modern cultivars were annotated with functions in various different aspects, indicating the CSS and CSA populations possibly underwent independent specific domestication processes. Our study indicated that transcriptome-based SNP-calling is an efficient and cost-effective method in untangling intraspecific phylogenetic relationships. This study provides a significant understanding of the cultivation history of the famous Chinese tea Xinyang Maojian and unravels the genetic basis of physiological and ecological differences between the two major tea subspecies.

Sweet pepper (<i>Capsicum annuumL.</i>) breeding on yield and fruits qualityaccording to the cultivar model for unheated soil greenhouses

Relevance. An important proviso for the commercially effective cultivation of vegetable crops in different types of greenhouses is high yield, which significantly depends on modern cultivars with different characteristics and properties. When creating a new cultivar, it is necessary to present its model in accordance with the expected ecological and agrotechnical conditions of planting, the purpose of use, the level of manifestation of morphological and biochemical characteristics, which together will ensure a high yield. The goal of research – to create early ripening, high-yielding cultivars of sweet pepper with high taste assessment of fresh fruits and content of biologically valuable substances.Materials and methods. The studies were conducted in 2015-2018 and 2020-2021 in the Belarusian State Agricultural Academy. The objects were 46 breeding lines of sweet pepper. An evaluation of fruits and plants morphological characteristics, yield traits, fruits biochemical composition, and tasting were carried out.Results. Valuable lines for breeding were selected with a gross yield of 5.60–6.71 kg/m2, with large fruits (150–220 g), thick pericarp (>7 mm),with a high content of biologically valuable substances and fruit quality 4.3–4.7 points. Lines with a complex of economically valuable traits including high tasting score, were transferred to the State Inspection for Testing and Protection of Plant Varieties and recommended for commercial use in the Republic of Belarus under the names Altyn, Chervonets, Karat, Goretsky Krasny, Garlachyk Zhovty and Chyrvony Magnat.

Tiller Number1 encodes an ankyrin repeat protein that controls tillering in bread wheat

Wheat (Triticum aestivum L.) is a major staple food for more than one-third of the world’s population. Tiller number is an important agronomic trait in wheat, but only few related genes have been cloned. Here, we isolate a wheat mutant, tiller number1 (tn1), with much fewer tillers. We clone the TN1 gene via map-based cloning: TN1 encodes an ankyrin repeat protein with a transmembrane domain (ANK-TM). We show that a single amino acid substitution in the third conserved ankyrin repeat domain causes the decreased tiller number of tn1 mutant plants. Resequencing and haplotype analysis indicate that TN1 is conserved in wheat landraces and modern cultivars. Further, we reveal that the expression level of the abscisic acid (ABA) biosynthetic gene TaNCED3 and ABA content are significantly increased in the shoot base and tiller bud of the tn1 mutants; TN1 but not tn1 could inhibit the binding of TaPYL to TaPP2C via direct interaction with TaPYL. Taken together, we clone a key wheat tiller number regulatory gene TN1, which promotes tiller bud outgrowth probably through inhibiting ABA biosynthesis and signaling.

Tracking population structure and phenology through time using ancient genomes from waterlogged white oak wood.

Whole genome characterizations of crop plants based on ancient DNA have provided unique keys for a better understanding of the evolutionary origins of modern cultivars, the pace and mode of selection underlying their adaptation to new environments and the production of phenotypes of interest. Although forests are among the most biologically rich ecosystems on earth and represent a fundamental resource for human societies, no ancient genome sequences have been generated for trees. This contrasts with the generation of multiple ancient reference genomes for important crops. Here, we sequenced the first ancient tree genomes using two white oak wood remains from Germany dating to the Last Little Ice Age (15th century CE, 7.3× and 4.0×) and one from France dating to the Bronze Age (1700 BCE, 3.4×). We assessed the underlying species and identified one medieval remains as a hybrid between two common oak species (Quercus robur and Q. petraea) and the other two remains as Q. robur. We found that diversity at the global genome level had not changed over time. However, exploratory analyses suggested that a reduction of diversity took place at different time periods. Finally, we determined the timing of leaf unfolding for ancient trees for the first time. The study extends the application of ancient wood beyond the classical proxies of dendroclimatology, dendrochronology, dendroarchaeology and dendroecology, thereby enhancing resolution of inferences on the responses of forest ecosystems to past environmental changes, epidemics and silvicultural practices.

Development and marker-trait relationships of functional markers for glutamine synthetase GS1 and GS2 homoeogenes in bread wheat

GS1 and GS2 genes encode, respectively, the main cytosolic and the plastidic isoforms of glutamine synthetase (GS). In the present study, the wheat GS1 and GS2 homoeogenes located in the A, B and D genome chromosomes have been sequenced in a group of 15 bread wheat varieties including landraces, old commercial varieties and modern cultivars. Phenotypic characterization by multi-environment field trials detected significant effects of specific GS homoeogenes on three of the seven agronomic and grain quality traits analyzed. Based on the gene sequence polymorphisms found, biallelic molecular markers that could facilitate marker-assisted breeding were developed for genes GS1A, GS2A and GS2D. The remaining genes encoding main wheat GS were excluded because of being monomorphic (GS1D) or too polymorphic (GS1B and GS2B) in the sequencing panel varieties. A collection of 187 Spanish bread wheat landraces was genotyped for these gene-based molecular markers. Data analyses conducted with phenotypic records reported for this germplasm collection in López-Fernández et al. (Plants-Basel 10: 620, 2021) have revealed the beneficial influence of some individual alleles on thousand-kernel weight (TKW), kernels per spike (KS) and grain protein content. Furthermore, genetic interactions between GS1A, a cytosolic GS isoform coding gene, and GS2A or GS2D, plastidic GS enzyme coding genes, were found to affect TKW and KS. The finding that some alleles at one locus may mask the effect of positive alleles at hypostatic GS loci should be kept in mind if gene pyramiding strategies are attempted for the improvement of N-use efficiency-related traits.

Distinctive Structure and Assembly of Phyllosphere Microbial Communities between Wild and Cultivated Rice.

Wild rice has been demonstrated to possess enriched genetic diversity and multiple valuable traits involved in disease/pest resistance and abiotic stress tolerance, which provides a potential resource for sustainable agriculture. However, unlike the plant compartments such as rhizosphere, the structure and assembly of phyllosphere microbial communities of wild rice remain largely unexplored. Through amplicon sequencing, this study compared the phyllosphere bacterial and fungal communities of wild rice and its neighboring cultivated rice. The core phyllosphere microbial taxa of both wild and cultivated rice are dominated with Pantoea, Methylobacterium, Nigrospora, and Papiliotrema, which are potentially beneficial to rice growth and health. Compared to the cultivated rice, Methylobacterium, Sphingomonas, Phaeosphaeria, and Khuskia were significantly enriched in the wild rice phyllosphere. The potentially nitrogen-fixing Methylobacterium is the dominated wild-enriched microbe; Sphingomonas is the hub taxon of wild rice networks. In addition, the microbiota of wild rice was more governed by deterministic assembly with a more complicated and stable community network than the cultivated rice. Our study provides a list of the beneficial microbes in the wild rice phyllosphere and reveals the microbial divergence between wild rice and cultivated rice in the original habitats, which highlights the potential selective role of wild rice in recruiting specific microbiomes for enhancing crop performance and promoting sustainable food production. IMPORTANCE Plant microbiota are being considered a lever to increase the sustainability of food production under a changing climate. In particular, the microbiomes associated with ancestors of modern cultivars have the potential to support their domesticated cultivars. However, few efforts have been devoted to studying the biodiversity and functions of microbial communities in the native habitats of ancestors of modern crop species. This study provides a list of the beneficial microbes in the wild rice phyllosphere and explores the microbial interaction patterns and the functional profiles of wild rice. This information could be useful for the future utilization of the plant microbiome to enhance crop performance and sustainability, especially in the framework of sustainable agroecosystems.

Metabolite Profiling of Wheat Response to Cultivar Improvement and Nitrogen Fertilizer.

Both genetic improvement and the application of N fertilizer increase the quality and yields of wheat. However, the molecular kinetics that underlies the differences between them are not well understood. In this study, we performed a non-targeted metabolomic analysis on wheat cultivars from different release years to comprehensively investigate the metabolic differences between cultivar and N treatments. The results revealed that the plant height and tiller number steadily decreased with increased ears numbers, whereas the grain number and weight increased with genetic improvement. Following the addition of N fertilizer, the panicle numbers and grain weights increased in an old cultivar, whereas the panicle number and grain number per panicle increased in a modern cultivar. For the 1950s to 2010s cultivar, the yield increases due to genetic improvements ranged from -1.9% to 96.7%, whereas that of N application ranged from 19.1% to 81.6%. Based on the untargeted metabolomics approach, the findings demonstrated that genetic improvements induced 1.4 to 7.4 times more metabolic alterations than N fertilizer supply. After the addition of N, 69.6%, 29.4%, and 33.3% of the differential metabolites were upregulated in the 1950s, 1980s, and 2010s cultivars, respectively. The results of metabolic pathway analysis of the identified differential metabolites via genetic improvement indicated enrichment in 1-2 KEGG pathways, whereas the application of N fertilizer enriched 2-4 pathways. Our results provide new insights into the molecular mechanisms of wheat quality and grain yield developments.

Almond [Prunus dulcis (Mill.) DA Webb] Processing Residual Hull as a New Source of Bioactive Compounds: Phytochemical Composition, Radical Scavenging and Antimicrobial Activities of Extracts from Italian Cultivars ('Tuono', 'Pizzuta', 'Romana').

In this study we developed a new extract, by the use of conventional solid-solvent extraction and a food-grade hydroalcoholic solvent, rich in phenolic and triterpenoid components from almon hull to be employed as functional ingredient in food, pharma and cosmetic sectors. Two autochthonous Sicilian cultivars ('Pizzuta' and 'Romana') and an Apulian modern cultivar ('Tuono') have been tested for the production of the extract. Results showed that the two Sicilian varieties, and in particular the 'Romana' one, present the best characteristics to obtain extracts rich in triterpenoids and hydroxycinnamic acids, useful for the production of nutraceutical supplements. About triterpenoids, the performance of the hydroalcoholic extraction process allowed to never go below 46% of recovery for 'Pizzuta' samples, with significantly higher percentages of recovery for 'Tuono' and 'Romana' extracts (62.61% and 73.13%, respectively) while hydroxycinnamic acids were recovered at higher recovery rate (84%, 89% and 88% for 'Pizzuta', 'Romana' and 'Tuono' extracts, respectively). Invitro antioxidant and antimicrobial activities exerted by the extracts showed promising results with P. aeruginosa being the most affected strain, inhibited up to the 1/8 dilution with 'Romana' extract. All the three tested extracts exerted an antimicrobial action up to 1/4 dilutions but 'Romana' and 'Pizzuta' extracts always showed the greatest efficacy.

Caracteres morfológicos que contribuem para o aumento da produtividade de cultivares de batata no Brasil

ABSTRACT A previous study revealed that modern potato cultivars used in Brazil have higher commercial tuber yield than old cultivars. The objective of the present study was to clarify which morphological characters influence the yield gain of modern cultivars. Two field experiments were performed in Brazil: in Guarapuava-PR and Brasilia-DF. The treatments consisted of six cultivars, classified according to origin and year of release: Bintje (European, 1910), Baronesa (Brazilian, 1955), Monalisa (European, 1982), Agata (European, 1990), Catucha (Brazilian, 1995) and BRS Clara (Brazilian, 2010). These were the main cultivars used in southern Brazil in the last 65 years and represent 100 years of breeding. A randomized complete block design with six treatments and four replications was used. The following plant morphological characters were evaluated at four growth stages (the beginning of plant development, the beginning of tuberization, maximum shoot growth and tuber bulking stages): leaf area index, specific leaf area, number of main stems, initiated and bulked tubers. At 15 days after emergence, modern cultivars have higher leaf area index and bulked tubers compared to older cultivars. Also, a larger number of mainstems and smaller specific leaf area were observed in modern cultivars. A high leaf area index at the beginning of the growing development combined with a large number of bulked tubers contributed to the increase of the yield potential of modern cultivars.

Genomic traces of Japanese malting barley breeding in two modern high-quality cultivars, 'Sukai Golden' and 'Sachiho Golden'.

Two modern high-quality Japanese malting barley cultivars, 'Sukai Golden' and 'Sachiho Golden', were subjected to RNA-sequencing of transcripts extracted from 20-day-old immature seeds. Despite their close relation, 2,419 Sukai Golden-specific and 3,058 Sachiho Golden-specific SNPs were detected in comparison to the genome sequences of two reference cultivars: 'Morex' and 'Haruna Nijo'. Two single nucleotide polymorphism (SNP) clusters respectively showing the incorporation of (1) the barley yellow mosaic virus (BaYMV) resistance gene rym5 from six-row non-malting Chinese landrace Mokusekko 3 on the long arm of 3H, and (2) the anthocyanin-less ant2 gene from a two-row Dutch cultivar on the long arm of 2H were detected specifically in 'Sukai Golden'. Using 221 recombinant inbred lines of a cross between 'Ishukushirazu' and 'Nishinochikara', another BaYMV resistance rym3 gene derived from six-row non-malting Japanese cultivar 'Haganemugi' was mapped to a 0.4-cM interval on the proximal region of 5H. Haplotype analysis of progenitor accessions of the two modern malting cultivars revealed that rym3 of 'Haganemugi' was independently introduced into 'Sukai Golden' and 'Sachiho Golden'. Residual chromosome 5H segments of 'Haganemugi' surrounding rym3 were larger in 'Sukai Golden'. Available results suggest possibilities for malting quality improvement by minimizing residual segments surrounding rym3.

Effect of moisture on photosynthesis and transpiration of buckwheat leaves

Currently, the issue of developing adaptive varieties of crops based on evolutionary principles is becoming urgent. The need to develop adaptive varieties for Russia is determined by the contrast of its natural and climatic conditions, global climate changes, and the increasing unpredictability of the weather. This task is highly relevant to the valuable food crop buckwheat, the yields of which are still low due to insufficient resistance of modern varieties to extreme environmental factors. Vegetation experiments to study the genotypic reaction of light and dark phases of photosynthesis of leaves on changes in soil moisture availability were carried out. During the period of buckwheat breeding from local samples to modern varieties the plants showed a significant trend in increasing the activity of photosynthesis and transpiration of plant leaves with a certain decrease in their resistance to moisture limitation. It was established that a decrease of soil moisture content from 70 to 30% of total moisture capacity caused, in modern cultivars, a mean decrease of fluorescence quantum yield by 52.5%, of electron-transport chain activity by 53.7%, of photosynthesis intensity by 66.5%, of transpiration intensity by 82.1%, whereas in local cultivars it decreased by 40.0%, 52.1%, 51.0%, and 76.1%, respectively.

Breeding and genomics approaches for improving phosphorus-use efficiency in grain legumes

Phosphorus (P) is an essential plant macronutrient, but P sources for plant growth are non-renewable, causing great concern for future sustainable agriculture and global food security. Thus, enhancing plant P-use efficiency (PUE) by improving P-acquisition and P-utilization efficiencies is urgently needed in various crops, including grain legumes, for intensive cropping systems. This review discusses how to harness the genetic variability in PUE traits across grain legume gene pools to improve PUE using various conventional breeding approaches and emerging breeding tools. The genetic architecture of PUE traits is complex, being quantitatively inherited and highly influenced by the environment. Thus, we discuss how the biparental QTL mapping approach has been used to dissect the genetic architecture of PUE traits. Unprecedented advances in legume genomics resources, especially high-throughput single nucleotide polymorphisms, have facilitated uncovering genomic regions related to PUE across the whole genome using a genome-wide association mapping approach. Likewise, the availability of complete genome sequence information, pangenome sequences, and the whole-genome resequencing approach have provided novel insights into structural variation, including presence/absence and copy number variations, underpinning PUE. Simultaneously, progress in functional genomics, including transcriptomics and computational biology, has facilitated the discovery of various underlying transcription factors and the corresponding downstream P signal perception genes and candidate gene(s) controlling PUE and conferring low-P tolerance in various legumes with putative function. We also discuss updated metabolomics and proteomics approaches that have improved our understanding of various gene networks, P-starvation signaling pathways, and P acquisition and utilization of molecular mechanisms important for PUE. Finally, we summarize how novel breeding schemes, including genomic selection, speed breeding, and emerging CRISPR/Cas9-based genome editing tools, will assist in designing P-use-efficient cultivars and adapting grain legumes to low-P environments. Thus, enhancing PUE by integrating various ‘omics’ approaches could improve P-acquisition and P-utilization efficiencies in various modern grain legume cultivars grown in intensive cropping systems to restrict P-fertilizer overuse and preserve the declining non-renewable global rock phosphate reservoir for securing an economical and sustainable future agriculture. • Phosphorus (P) is one of the most essential nutrients required for plant growth and development. • P fertilizers being non-renewable, judicious utilization of P fertilizer is urgently needed for sustaining legume yield for ensuring global food security. • Plants have evolved several molecular, physiological and biochemical mechanisms to sense, acquire and utilize soil P and adapt under P impoverished environments. • ‘Omics’ approach could greatly assist in unraveling the underlying genomic regions with their function contributing to improving phosphorus use efficiency in legume crops.

Analysis of Floral Scent Components of <i>Rosa foetida</i> Herrm., a Rose with an Unpleasant Fragrance

Rosa foetida Herrm. is an important wild rose that contributed to the birth of modern yellow cultivars. It is also well known for the unpleasant odor, not prevalent in other roses, emanating from its petals. We analyzed the floral scent of R. foetida and its sport cultivars, R. foetida var. bicolor (Jacq.) Willm. and R. foetida f. persiana (Lem.) Rehd., to identify the causative compounds for their offensive odor. Fatty acid derivatives 2,4-decadienal (2,4-DA), 2,4-decadienol (2,4-DO), and (Z)-jasmone were detected by gas chromatography-mass spectrometry along with several terpenoids, phenylpropanoids, and hydrocarbons. Among them, 2,4-DA and 2,4-DO were identified as the causative compounds of the offensive odor. This is the first detection of these fatty acid derivatives in the scent of rose flowers. We also analyzed the floral scent of eight descendant cultivars of R. foetida: ‘Agnes’, ‘Harison’s Yellow’, ‘Rhodophile Gravereaux’, ‘Schloss Seusslitz’, ‘Soleil d’Or’, ‘Star of Persia’, ‘The Queen Alexandra Rose’, and ‘Williams’ Double Yellow’. 2,4-DA and 2,4-DO were only detected in the smell of ‘Star of Persia’. No other descendant was found to emit these fatty acids. This is the first analysis of an unpleasant odor in roses.

EIGHT OLD CULTIVARS OF APPLE TREES – AN EVALUATION OF THEIR POTENTIAL FOR USE BY THE PROCESSING INDUSTRY

Background. Fruit of old cultivars may contain more micro- and macronutrients and polyphenols than modern tree cultivars. This paper presents the results of a study on eight old cultivars of apple trees. The fruit was gathered in the Wolin National Park (Woliński Park Narodowy) from old uncultivated trees. Results and conclusions. Despite the lack of tree care, the fruit of all the cultivars studied contained small amounts of harmful heavy metals and nitrates. Different criteria are used to evaluate fruit by consumers and the processing industry. For consumers, taste is important, and a low sugar-to-acid ratio makes fruit much tastier. The Roter Herbstkalvill cultivar, despite containing the least sugar of all the cultivars tested, has the lowest sugar-to-acid ratio (3.3). The highest content of health-promoting polyphenolic compounds was found in the fruit of the following cultivars: Roter Herbstkalvill (734 mg/100 g DM) and Kaiser Alexander (701 mg/100 g DM). Due to their high dry matter content, the Geflammter Kardinal and Boikenapfel cultivars will be the best choice for the processing industry. Whereas cultivars with a low sugar content, which caramelizes at high temperatures - Roter Herbstkalvill and Weisser Winterkalvill - will be useful for flour production and baking.

Особенности органогене за труднокул ьтивируемых ни зкорослых сортов вишни обыкновенной (Prunus ceras us L.) в кул ьтуре in vitro

The article presents the results of research on clonal micropropagation of sour cherry (Prunus cerasus L.) which is difficult to reproduce at the proliferation stage by traditional methods. A number of modern winter-hardy domestic cultivars of P. cerasus are promising for plantation cultivation of this crop in the Nonchernozem zone of the European part of Russia. The method of clonal micropropagation is advisable to obtain a large amount of healthy and genetically homogeneous rootstocks of fruit crops. Regenerated plants of P. cerasus of low-growing, mid-season and winter-hardy cultivars Assol’ and Shokoladnitsa were used as research objects. The growth and developmental features of P. cerasus regenerated plants were studied during in vitro cultivation on a QL nutrient medium supplemented with growth regulators of the cytokinin group (6-BAP, thidiazuron, zeatin) in different concentrations. The highest indicators for the length of microshoots (average 13.4 mm) and the number of leaves (average 6.0 pcs.) of P. cerasus plants in in vitro culture are recorded for the Shokoladnitsa cultivar. The maximum length of microshoots of P. cerasus Assol’ cultivar is observed on the 60th day of cultivation on a QL nutrient medium with the addition of zeatin at a concentration of 0.3 mg/l (10.5 mm) and thidiazuron at a concentration of 0.3 mg/l (9.8 mm), while the maximum number of leaves (7.8 pieces) is observed with addition of 0.3 mg/l zeatin. The maximum length of microshoots of P. cerasus of the Shokoladnitsa cultivar is observed when grown for 60 days on a QL nutrient medium with the addition of 6-BAP at concentrations of 0.5 mg/l (17.7 mm) and 1.0 mg/l (14.2 mm), while the maximum number of leaves (7.2 pieces) is observed with addition of 0.3 mg/l zeatin.

Large-scale genotyping and phenotyping of a worldwide winter wheat genebank for its use in pre-breeding

Plant genetic resources (PGR) stored at genebanks are humanity’s crop diversity savings for the future. Information on PGR contrasted with modern cultivars is key to select PGR parents for pre-breeding. Genotyping-by-sequencing was performed for 7,745 winter wheat PGR samples from the German Federal ex situ genebank at IPK Gatersleben and for 325 modern cultivars. Whole-genome shotgun sequencing was carried out for 446 diverse PGR samples and 322 modern cultivars and lines. In 19 field trials, 7,683 PGR and 232 elite cultivars were characterized for resistance to yellow rust - one of the major threats to wheat worldwide. Yield breeding values of 707 PGR were estimated using hybrid crosses with 36 cultivars - an approach that reduces the lack of agronomic adaptation of PGR and provides better estimates of their contribution to yield breeding. Cross-validations support the interoperability between genomic and phenotypic data. The here presented data are a stepping stone to unlock the functional variation of PGR for European pre-breeding and are the basis for future breeding and research activities.

RicePedigree: Rice Pedigree Database for Documentation and Assistance in Rice Breeding

For the purpose of breeding documentation, researchers and breeders kept handwritten records of the breeding history, including parental information and breeding methods. The cultivars were used again as parents for further breeding, and modern cultivars of rice have a wide range of alleles from many generations of parents and ancestors. To understand such a breeding history, it is necessary to ask around for relevant information, which is then usually documented in Excel or Word by multiple breeders or breeding institutes. Here, we constructed RicePedigree, which contains the breeding history of rice based on the documents provided by the Rural Development Administration (RDA) in Korea. We devised a simple method for collecting a breeding history and storing it in a database. RicePedigree is a web-based application on the database that facilitates researchers’ and breeders’ utilization of the breeding history of rice. Based on the query cultivar name, it will return a hierarchical tree of breeding histories and a list of cultivars and breeding lines that contain query cultivars in their breeding histories. This app would be a good way to review and keep track of information about current and future cultivars.

A Haplotype-Based GWAS Identified Trait-Improving QTL Alleles Controlling Agronomic Traits under Contrasting Nitrogen Fertilization Treatments in the MAGIC Wheat Population WM-800.

The multi-parent-advanced-generation-intercross (MAGIC) population WM-800 was developed by intercrossing eight modern winter wheat cultivars to enhance the genetic diversity present in breeding populations. We cultivated WM-800 during two seasons in seven environments under two contrasting nitrogen fertilization treatments. WM-800 lines exhibited highly significant differences between treatments, as well as high heritabilities among the seven agronomic traits studied. The highest-yielding WM-line achieved an average yield increase of 4.40 dt/ha (5.2%) compared to the best founder cultivar Tobak. The subsequent genome-wide-association-study (GWAS), which was based on haplotypes, located QTL for seven agronomic traits including grain yield. In total, 40, 51, and 46 QTL were detected under low, high, and across nitrogen treatments, respectively. For example, the effect of QYLD_3A could be associated with the haplotype allele of cultivar Julius increasing yield by an average of 4.47 dt/ha (5.2%). A novel QTL on chromosome 2B exhibited pleiotropic effects, acting simultaneously on three-grain yield components (ears-per-square-meter, grains-per-ear, and thousand-grain-weight) and plant-height. These effects may be explained by a member of the nitrate-transporter-1 (NRT1)/peptide-family, TaNPF5.34, located 1.05 Mb apart. The WM-800 lines and favorable QTL haplotypes, associated with yield improvements, are currently implemented in wheat breeding programs to develop advanced nitrogen-use efficient wheat cultivars.

Harnessing underutilized gene bank diversity and genomic prediction of cross usefulness to enhance resistance to Phytophthora cactorum in strawberry.

The development of strawberry (Fragaria × ananassa Duchesne ex Rozier) cultivars resistant to Phytophthora crown rot (PhCR), a devastating disease caused by the soil-borne pathogen Phytophthora cactorum (Lebert & Cohn) J. Schröt., has been challenging partly because the resistance phenotypes are quantitative and only moderately heritable. To develop deeper insights into the genetics of resistance and build the foundation for applying genomic selection, a genetically diverse training population was screened for resistance to California isolates of the pathogen. Here we show that genetic gains in breeding for resistance to PhCR have been negligible (3% of the cultivars tested were highly resistant and none surpassed early 20th century cultivars). Narrow-sense genomic heritability for PhCR resistance ranged from 0.41 to 0.75 among training population individuals. Using multivariate genome-wide association studies (GWAS), we identified a large-effect locus (predicted to be RPc2) that explained 43.6-51.6% of the genetic variance, was necessary but not sufficient for resistance, and was associated with calcium channel and other candidate genes with known plant defense functions. The addition of underutilized gene bank resources to our training population doubled additive genetic variance, increased the accuracy of genomic selection, and enabled the discovery of individuals carrying favorable alleles that are either rare or not present in modern cultivars. The incorporation of an RPc2-associated single-nucleotide polymorphism (SNP) as a fixed effect increased genomic prediction accuracy from 0.40 to 0.55. Finally, we show that parent selection using genomic-estimated breeding values, genetic variances, and cross usefulness holds promise for enhancing resistance to PhCR in strawberry.

Differentiated Weed-Suppressive Ability of Modern and Old Durum Wheat Cultivars after Long-Term Cultivation under Semi-Arid Climate.

Durum wheat (Triticum turgidum spp. durum) is one of the most important grain crops cultivated across the Mediterranean Basin, where a strong return to local landraces cultivation is occurring to meet the market demand for high-quality food and low-input cropping systems. A characterisation of the long-term effect (10 years) of durum wheat landraces and modern cultivars on the potential and real weed flora is still lacking. Hence, a multilocation trial over 10 farms in Central-Eastern Sicily was carried out to investigate the repeated cultivation of several old landraces (OLD) and modern cultivars (MOD) on the abundance and diversity of weed flora. Overall, OLD was associated with a 47% reduction of the soil seedbank size and to -64% of the aboveground weed biomass compared to MOD. In addition, diversity indices pointed out a high similarity between MOD and OLD farm groups for the soil seedbank, while a lower diversity was found in OLD for aboveground weed communities. From the principal component analysis emerged that the species compositions of MOD and OLD were quite separated for both soil seedbank and real flora, with the latter showing few specific associations with major weeds. These findings demonstrated the indirect effect of durum wheat landraces in sustainably reducing weed pressure without the adoption of chemical weed control.