Landrace Cultivars Research Articles

In Dabouki Land: Interdisciplinary notes on the cultural history of a landrace grape cultivar in Israel

Cultivated for millennia, the grapevine held a special status as one of the most important fruits in the historical Levant and the Mediterranean world. However, since past farmers typically did not leave written accounts of their activities, viticulture history is often shrouded in ambiguity, especially concerning the classification of grapevine landrace varieties. Hence, the study of archaic viticulture relies heavily on methodological fusion to unravel its more readily discernible biological and oral traditions. We therefore merged archaeological fieldwork, historical archival analysis, field geography and ethnographic interviews to collect multifarious data on the Dabouki grapevine. Our analytical synthesis enabled us to depict how, over the course of history, diverse communities variously grew this cultivar in dryland vineyards. The cultural history of the Dabouki stretches from at least the Ottoman era, when it was widely planted throughout the region under various names, to its current revival by enterprising Israeli and Palestinian winemakers. The majority of our research was conducted within a unique environmental corridor in the western Negev of Israel where dense concentrations of relic Dabouki grapevine survive. Our paper surveys the cultural history of the Dabouki grape as a flagship cultivar in the intergenerational horticultural regimes of arid land farmers in the western Negev of the southern Levant. Remarkably, archaic Negev viticulturalists used the same cultivars across successive historical periods and varying socioeconomic contexts. As such, the paper illustrates that arid regions with longstanding winegrowing traditions are ideal for locating endemic grapevines that apparently can withstand challenging growing conditions. Focusing on the enduring legacy of the Dabouki, we suggest how historical knowledge of ancient dryland farming systems and landrace cultivars can bolster the sustainability of contemporary viticulture.

Comparative 1H NMR-Based Metabolomics of Traditional Landrace and Disease-Resistant Chili Peppers (Capsicum annuum L.).

Chili peppers (Capsicum annuum L.) are economically valuable crops belonging to the Solanaceae family and are popular worldwide because of their unique spiciness and flavor. In this study, differences in the metabolomes of landrace (Subicho) and disease-resistant pepper cultivars (Bulkala and Kaltanbaksa) widely grown in Korea are investigated using a 1H NMR-based metabolomics approach. Specific metabolites were abundant in the pericarp (GABA, fructose, and glutamine) and placenta (glucose, asparagine, arginine, and capsaicin), highlighting the distinct physiological and functional roles of these components. Both the pericarp and placenta of disease-resistant pepper cultivars contained higher levels of sucrose and hexoses and lower levels of alanine, proline, and threonine than the traditional landrace cultivar. These metabolic differences are linked to enhanced stress tolerance and the activation of defense pathways, imbuing these cultivars with improved resistance characteristics. The present study provides fundamental insights into the metabolic basis of disease resistance in chili peppers, emphasizing the importance of multi-resistant varieties to ensure sustainable agriculture and food security. These resistant varieties ensure a stable supply of high-quality peppers, contributing to safer and more sustainable food production systems.

Technological quality of common bean landraces from organic cropping system

Beans are an important constituent of the Brazilian diet, and the search for cultivars with good culinary characteristics and adapted to the place of cultivation is necessary. It is known that there is a wide genetic diversity for common bean landrace cultivars. Still, little is known experimentally about the behavior of these cultivars when produced under organic cultivation. This work aimed to evaluate the technological quality of common bean landraces produced under organic cropping system. Twenty-six cultivars were used, four commercial and twenty-two landraces, originating from the Active Bean Germplasm Bank (BAF) of Santa Catarina State University – Agroveterinary Sciences Center (UDESC/CAV), produced in organic and conventional cultivation, in two crops. Cooking time and resistance, percentage of water absorption and broken grains and total soluble solids were evaluated. The shortest cooking time for the grains cultivated in the organic system (18 to 22 minutes) was obtained. The cultivars that had a percentage of unbroken grains between 60 and 80% showed a higher content of total soluble solids in the broth. Based on the genetic diversity for technological quality in organic cropping system, the use of cultivars, BAFs: 60, 23, 81, 13, 68, 55, 75 and 36 are indicated to integrate genetic improvement programs or to be used by small farmers for bean production.

A Step-by-step Protocol for Crossing and Marker-Assisted Breeding of Asian and African Rice Varieties.

Improving desirable traits of popular rice varieties is of particular importance for small-scale food producers. Breeding is considered the most ecological and economic approach to improve yield, especially in the context of pest and pathogen-resistant varieties development. Being able to cross rice lines is also a critical step when using current transgene-based genome editing technologies, e.g., to remove transgenes. Moreover, rice breeders have developed accelerated breeding methods, including marker-assisted backcross breeding (MABB) to develop novel rice varieties with in-built resistance to biotic and abiotic stressors, grain, and nutritional quality. MABB is a highly efficient and cost-effective approach in accelerating the improvement of recipient variety by introgressing desirable traits, especially from landrace cultivars and wild rice accessions. Here, we provide a detailed protocol including video instructions for rice crossing and MABB to introgress target trait(s) of interest into the elite rice line. Further, we also highlight tips and tricks to be considered for a successful crossing and MABB. Key features • This protocol provides detailed information on techniques for crossing rice varieties and for breeding rice varieties with new traits • The protocol includes instructions for making rice crosses as well as MABB • The protocol provides beginners with detailed instructions including troubleshooting guides Graphical overview Illustration of crosses of rice lines and marker-assisted backcross breeding (created with BioRender.com).

Genome resources for the elite bread wheat cultivar Aikang 58 and mining of elite homeologous haplotypes for accelerating wheat improvement

Despite recent progress in crop genomics studies, the genomic changes brought about by modern breeding selection are still poorly understood, thus hampering genomics-assisted breeding, especially in polyploid crops with compound genomes such as common wheat (Triticum aestivum). In this work, we constructed genome resources for the modern elite common wheat variety Aikang 58 (AK58). Comparative genomics between AK58 and the landrace cultivar Chinese Spring shed light on genomic changes that occurred through recent varietal improvement. We also explored subgenome diploidization and divergence in common wheat and developed a homoeologous locus–based genome-wide association study (HGWAS) approach, which was more effective than single homoeolog–based GWAS in unraveling agronomic trait–associated loci. A total of 123 major HGWAS loci were detected using a genetic population derived from AK58 and Chinese Spring. Elite homoeologous haplotypes, formed by combinations of subgenomic homoeologs of the associated loci, were found in both parents and progeny, and many could substantially improve wheat yield and related traits. We built a website (available at https://triticeae.henau.edu.cn/aikang58/) where users can download genome assembly sequence and annotation data for AK58, perform blast analysis, and run JBrowse. Our work enriches genome resources for wheat, provides new insights into genomic changes during modern wheat improvement, and suggests that efficient mining of elite homoeologous haplotypes can make a substantial contribution to genomics-assisted breeding in common wheat and other polyploid crops.

Metabolic profiles of Sri Lankan cassava mosaic virus-infected and healthy cassava (Manihot esculenta Crantz) cultivars with tolerance and susceptibility phenotypes

BackgroundCassava mosaic disease (CMD) of cassava (Manihot esculenta Crantz) has expanded across many continents. Sri Lankan cassava mosaic virus (SLCMV; family Geminiviridae), which is the predominant cause of CMD in Thailand, has caused agricultural and economic damage in many Southeast Asia countries such as Vietnam, Loas, and Cambodia. The recent SLCMV epidemic in Thailand was commonly found in cassava plantations. Current understanding of plant–virus interactions for SLCMV and cassava is limited. Accordingly, this study explored the metabolic profiles of SLCMV-infected and healthy groups of tolerant (TME3 and KU50) and susceptible (R11) cultivars of cassava. Findings from the study may help to improve cassava breeding, particularly when combined with future transcriptomic and proteomic research.ResultsSLCMV-infected and healthy leaves were subjected to metabolite extraction followed by ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS/MS). The resulting data were analyzed using Compound Discoverer software, the mzCloud, mzVault, and ChemSpider databases, and published literature. Of the 85 differential compounds (SLCMV-infected vs healthy groups), 54 were differential compounds in all three cultivars. These compounds were analyzed using principal component analysis (PCA), hierarchical clustering dendrogram analysis, heatmap analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation. Chlorogenic acid, DL-carnitine, neochlorogenic acid, (E)-aconitic acid, and ascorbyl glucoside were differentially expressed only in TME3 and KU50, with chlorogenic acid, (E)-aconitic acid, and neochlorogenic acid being downregulated in both SLCMV-infected TME3 and KU50, DL-carnitine being upregulated in both SLCMV-infected TME3 and KU50, and ascorbyl glucoside being downregulated in SLCMV-infected TME3 but upregulated in SLCMV-infected KU50. Furthermore, 7-hydroxycoumarine was differentially expressed only in TME3 and R11, while quercitrin, guanine, N-acetylornithine, uridine, vorinostat, sucrose, and lotaustralin were differentially expressed only in KU50 and R11.ConclusionsMetabolic profiling of three cassava landrace cultivars (TME3, KU50, and R11) was performed after SLCMV infection and the profiles were compared with those of healthy samples. Certain differential compounds (SLCMV-infected vs healthy groups) in different cultivars of cassava may be involved in plant–virus interactions and could underlie the tolerance and susceptible responses in this important crop.

English

High-yielding and disease-resistant hybrid plant cultivars recently developed by breeders need evaluation for end-use. This study evaluated the influence of processing methods on the sensory acceptability of products (plantain chips, fried ripe plantains called “dodo” in Nigeria, boiled unripe and ripe plantains, and "amala," a dough, as it is called in Nigeria when unripe and ripe plantain flour is reconstituted in hot water) from selected hybrid plantain cultivars. Pita 26, Pita 27, Mbi egome, and Agbagba landrace cultivars were studied. Plantain pulps were subjected to frying (170°C for 2 min), boiling (100°C for 15 min), and drying (65°C for 48 h) at unripe and ripe stages before analyses. These food items were subjected to sensory evaluation. The panel of 20 people evaluated samples for texture, taste, flavor, appearance, color, stretchability, moldability, mouthfeel, and overall preference on a 9-point hedonic scale. The sensory studies showed statistically significant differences (P<0.05) between products and processing methods significantly affected the cultivars' sensory parameters and essential minerals and vitamins. Products from the Mbi egome cultivar were adjudged acceptable in terms of overall quality, followed by the Agbagba local landrace cultivar. The data in this study have shown that hybrid plantains have the potential to be used industrially.   Key words: Consumers acceptability, value added products, hybrid plantain, organoleptic. 

Valorization of different landrace and commercial sorghum (Sorghum bicolor (L.) Moench) straw varieties by anaerobic digestion

AbstractTo reduce the impact on the environment and enhance the sustainability of resources, it is necessary to promote and strengthen the use of landrace cultivars that advocate regenerative agriculture. In this study, the growth and development as well as the anaerobic digestion (AD) of six different landrace cultivars, two commercial hybrids cultivars and a public genotype of Sorghum bicolor have been evaluated. The landrace cultivars, in general, presented greater heights, biomass yields and compactness shoots as well as similar or an improvement in grain production compare to the commercial varieties. The AD of the different sorghum straws was performed in batch mode at mesophilic temperature (35°C). The landrace cultivar Zahina (ZH) obtained the highest final methane yield (413 ± 79 NL CH4 kg−1 VS, volatile solids) but the landrace cultivars Zahina gigante (ZHG) and Trigomillo (TG) were the ones that obtained the highest methane per biomass production (13.7 and 12.7 NL CH4 shoot unit−1, respectively). By contrast, the commercial varieties were the ones that obtained the lowest methane yields. Two mathematical models, first‐order kinetics and the Transference Function model, were used to fit the experimental data with the aim of describing and simulating the anaerobic biodegradation of these S. bicolor straw varieties and obtaining the kinetic constants. Both models allowed for adequately fitting the experimental results of methane production with time. In particular, the fastest biomethanization occurred using the commercial variety PR88Y20 (PR88) (specific rate constant k = 0.148 ± 0.008 days−1), while the slowest one was obtained from Panizo (PAN) variety (k = 0.064 ± 0.005 days−1). In addition, the highest values of the maximum methane production rate, Rm, were attained for the varieties ZH and PR88, which were 87.1% and 71.3% higher than that achieved for the PAN variety, which exhibited the lowest value.

Growth, yield and quality of selected sweet potato (Ipomoea batatas [l.] Lam.), lines under varying soil moisture conditions

Sweet Potato (Ipomoea batatas [L.] has increasing potential as a food security crop in Kenya. However, its’ production is relatively low compared to its potential production which is attributed to drought conditions alongside use of local landrace cultivars that are quite low yielding. A study was conducted at Meru University of Science and Technology in Kenya in 2020-2021 to assess the performance of selected improved sweet potato lines under varied watering regimes. Two selected sweet potato varieties were used; CIP 106988.1 (Naspot13) and CIP 112286.1(Margarette), and a farmer-preferred variety Kemb-10. The varieties were subjected to three watering regimes (i) Severe stress (SS), 4 WAE (ii) Moderate Stress (MS), 9 WAE and (iii) well watered to maturity. A randomized complete block design in a split plot, with water treatment as the main plot and varieties as subplot with 3 replicates was used. There was no significant interaction between moisture treatments and varieties. Water treatments significantly (p≤0.05) affected vine length, number of leaves and tuber yield. Plants under severe stress had significantly lower vine length, branches and leaves. Under Moderate stress 9 WAE, plants experienced significant reduction in vine length, leaves and branches compared to the well watered. However, this reduction was less compared to severe stress. The reduced vine length and tuber yield is attributed to reduced cell division, elongation and assimilates partitioning. Tuber numbers correlated with leaves (r = 0.63*, 0.74*), and vine length (r = 0.62*, 0.76*). This positive correlation implies that if drought significantly reduces number of leaves and vine length, it reduces tuber yield indicating effect of drought on tuber yield can be estimated by measuring tuber length and number of leaves. Based on findings, ensuring the crop obtains enough moisture during the first nine weeks after planting is recommendable whereas Naspot13 is suitable for the area considering its higher productivity.

The prevalence of deleterious mutations during the domestication and improvement of soybean

Soybean (Glycine max L.) is a protein and oil crop grown worldwide. Its fitness may be reduced by deleterious mutations, whose identification and purging is desirable for crop breeding. In the published whole-genome re-sequenced data of 2214 soybean accessions, including 221 wild soybean, 1132 landrace cultivars and 861 improved soybean lines, we identified 115,275 deleterious single-nucleotide polymorphisms (SNPs). Numbers of deleterious alleles increased from wild soybeans to landraces and decreased from landraces to modern improved lines. Genes in selective-sweep regions showed fewer deleterious mutations than the remaining genes. Deleterious mutations explained 4.3%–48% more phenotypic variation than randomly selected SNPs for resistance to soybean cyst nematode race 2 (SCN2), soybean cyst nematode race 3 (SCN3) and soybean mosaic virus race 3 (SMV3). These findings illustrate how mutation load has shifted during soybean domestication, expansion and improvement and provide candidate sites for breeding out deleterious mutations in soybean by genome editing and/or conventional breeding focused on the selection of progeny with fewer deleterious alleles.

Growth, yield and quality of selected sweet potato (Ipomoea batatas [L.] lam.), lines under varying soil moisture conditions

Sweet Potato (Ipomoea batatas [L.] has increasing potential as a food security crop in Kenya. However, its production is relatively low compared to its potential production attributed to drought conditions alongside use of local landrace cultivars that are quite low yielding. A study was conducted at Meru University in 2020-2021 to assess the performance of selected improved sweet potato lines under varied watering regimes. Two selected sweet potato varieties were used; Naspot 13 and Margarette and a farmer-preferred variety, kemb-10. The varieties were subjected to three different watering regimes (i) Continuous water deficit 30 DAE (ii) Continuous water deficit 60 DAE and (iii) well-watered to maturity. A randomized complete block design in a split plot, with water treatment as the main plot and varieties as subplot with 3 replicates was used. There was no significant interaction between varieties and water regimes. Watering regimes significantly (p≤0.05) affected vegetative growth and yield. Plants under continuous water deficit from 30 DAE had significantly lower vine length, number of branches and leaves. Under continuous water deficit from 60DAE, plants experienced significant reduction in vine length, number of leaves and branches compared to control plants. However, this reduction was less compared to 30DAE. Margerete had significantly lower vine length, number of branches and leaves (41.01% 11.2% and 44.3%) respectively. Kemb 10 had a significantly higher tuber diameter and tuber length, 101% and 91.05% respectively. The vegetative growth and yield of Naspot 3 was comparable to Kemb 10. Naspot had 89.4% increases in number of tubers. It’s concluded that varieties tested responded similarly to water deficit, with larger vegetative and yield reductions at 30DAE. Based on findings, planting earlier is recommendable for crop establishment to escape water stress whereas Naspot 13 is more suitable for the area considering its higher growth and yield.

Exploiting genetic variation from unadapted germplasm—An example from improvement of sorghum in Ethiopia

Societal Impact StatementThe productivity of sorghum in Ethiopia has been largely limited by rain‐fed conditions because farmers tend to use local drought‐tolerant but low‐yielding landraces, as high‐yielding and late‐maturing landrace cultivars risk failure due to drought. Addressing such issues often requires a far‐reaching approach to identify and incorporate new traits into a gene pool, followed by a period of selection to re‐establish an overall adaptive phenotype. The sorghum backcross nested association mapping (BC‐NAM) population developed in this study increases the genetic diversity available in Ethiopian elite adapted sorghum germplasm, providing new scope to improve food security in a region known for periodic devastating droughts.Summary As the center of diversity for sorghum, Sorghum bicolor (L.) Moench, elite cultivars selected in Ethiopia are of central importance to sub‐Saharan food security. Despite being presumably well adapted to their center of diversity, elite Ethiopian sorghums nonetheless experience constraints to productivity, for example, associated with shifting rainfall patterns associated with climate change. A sorghum backcross nested association mapping (BC‐NAM) population developed by crossing 13 diverse lines pre‐identified to have various drought resilience mechanisms with an Ethiopian elite cultivar, Teshale, was tested under three rain‐fed environments in Ethiopia. Twenty‐seven, 15, and 15 quantitative trait loci (QTLs) with predominantly small additive effects were identified for days to flowering, days to maturity, and plant height, respectively. Many associations detected in this study corresponded closely to known or candidate genes or previously mapped QTLs, supporting their validity. The expectation that genotypes such as Teshale from the center of diversity tend to have a history of strong balancing selection, with novel variations more likely to persist in small marginal populations, was strongly supported in that for these three traits, nearly equal numbers of alleles from the donor lines conferred increases and decreases in phenotype relative to the Teshale allele. Such rich variation provides a foundation for selection to arrive at a new “adaptive peak,” exemplifying the nature of efforts that may be necessary to adapt many crops to new climate extremes.

Medicinal Uses, Nutraceutical Potentials and Traditional Farm Production of Bambara Beans and Pigeon Pea


 Bambara groundnut (BGN) [Vigna subterranean (L) Verdc] and Pigeon pea [Cajanus cajan (L.) Millspaugh] are grain legume species grown in tropical and subtropical parts of the world. Both legume grains are highly nutritious and have been used as food and medicine for both humans and animals. However, Bambara groundnut and pigeon pea are still highly underutilized and produced in low quantities despite their nutritional benefits. This review examines nutritional properties, medicinal uses, nutraceutical potential and the limitations in the utilization of bambara groundnut and pigeon pea. Scholarly articles and organization white papers were searched for using various word combinations of traditional farm practices, modern agricultural practices, traditional medicinal uses, nutritional composition, biochemical composition, Bambara groundnut and pigeon pea. Bambara groundnut and pigeon pea are popularly used as medicine in many parts of Africa. Both species are rich sources of bioactive compounds and several studies have documented their efficacy against several diseases. Bambara groundnut has been used to treat polymenorrhea, venereal diseases, cataracts, and morning sickness. The stem, leaves, seeds, and roots of pigeon pea plant has been used to treat many diseases in many parts of the world. Bambara groundnut has been found to be a potential dietary probiotic, antioxidant, antibiotic and anticancer. Hypocholesterolemic, anticancer, hepatoprotective, antidiabetic and antimicrobial activities have been documented for pigeon pea as well. However, low yield, unfavourable land tenure systems, unimproved varieties, diseases, and pests are the major constraints of the traditional production of bambara groundnut and pigeon pea. Both legume grain species are important sources of nutrients and they both possess strong potentials to be nutraceutical agents against many diseases including malnutrition. However, advanced and intensive research on pest management, improvement of the traditional landrace cultivars for improved yield and palatability as well as formulation of favourable land tenure policies are recommended for better adoption, utilization and commercialization of bambara groundnut and pigeon pea.

Candidate powdery mildew resistance gene in wheat landrace cultivar Hongyoumai discovered using SLAF and BSR-seq

BackgroundWheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important disease affecting wheat production. Planting resistant cultivars is an effective, safe, and economical method to control the disease. Map construction using next-generation sequencing facilitates gene cloning based on genetic maps and high-throughput gene expression studies. In this study, specific-locus amplified fragment sequencing (SLAF) was used to analyze Huixianhong (female parent), Hongyoumai (male parent) and two bulks (50 homozygous resistant and 50 susceptible F2:3 segregating population derived from Huixianhong × Hongyoumai to determine a candidate gene region for resistance to powdery mildew on the long arm of chromosome 7B in wheat landrace Hongyoumai. Gene expressions of candidate regions were obtained using bulked segregant RNA-seq in 10 homozygous resistant and 10 susceptible progeny inoculated by Bgt.. Candidate genes were obtained using homology-based cloning in two parents.ResultsA 12.95 Mb long candidate region in chromosome 7BL was identified, and five blocks in SLAF matched the scaffold of the existing co-segregation marker Xmp1207. In the candidate region, 39 differentially expressed genes were identified using RNA-seq, including RGA4 (Wheat_Chr_Trans_newGene_16173)—a disease resistance protein whose expression was upregulated in the resistant pool at 16 h post inoculation with Bgt. Quantitative reverse transcription (qRT)-PCR was used to further verify the expression patterns in Wheat_Chr_Trans_newGene_16173 that were significantly different in the two parents Hongyoumai and Huixianhong. Two RGA4 genes were cloned based on the sequence of Wheat_Chr_Trans_newGene_16173, respectively from two parent and there was one amino acid mutation: S to G in Huixianhong on 510 loci.ConclusionThe combination of SLAF and BSR-seq methods identified a candidate region of pmHYM in the chromosome 7BL of wheat landrace cultivar Hongyoumai. Comparative analysis between the scaffold of co-segregating marker Xmp1207 and SLAF-seq showed five matching blocks. qRT-PCR showed that only the resistant gene Wheat_Chr_Trans_newGene_16173 was significantly upregulated in the resistant parent Hongyoumai after inoculation with Bgt, and gene cloning revealed a difference in one amino acid between the two parent genes, indicating it was involved in the resistance response and may be the candidate resistance gene pmHYM.

Physicochemical, Structural, Thermal and Rheological Properties of Flour and Starch Isolated from Avocado Seeds of Landrace and Hass Cultivars.

The objective of this study was to obtain and characterize flours and starches from the avocado seeds of Hass and landrace cultivars. The morphological, physical-chemical, structural, thermal and rheological characteristics were evaluated. The flour yield of the Hass and landrace cultivars was 41.56 to 46.86% (w/w), while for starch, it was 35.47 to 39.57% (w/w) (cv. Hass and landrace, respectively). Scanning electron microscopy (SEM) revealed the presence of oval starch granules and other particles in flour, in contrast to flours, starches showed lower ash, proteins and lipids content. However, the amylose content was higher in starches (42.25–48.2%). Flours showed a higher gelatinization temperature (Tp = 73.17–73.62 °C), and their starches presented greater gelatinization enthalpy (∆Hgel = 11.82–13.43 J/g). All samples showed a B-type diffraction pattern, and the crystallinity was higher in the flours. The rheological analysis (flow curves and viscoelastic tests) evidenced a pseudoplastic (n = 0.28–0.36) behavior in all samples analyzed, but the consistency index (k) was higher in starches. In general, the flours and starches from avocado seeds presented interesting proximal, thermal and functional properties for possible application in food systems, and these findings could contribute to the revaluation of this by-product.

CerealsDB: A Whistle-Stop Tour of an Open Access SNP Resource.

The CerealsDB website, created by members of the Functional Genomics Group at the University of Bristol, provides access to a database containing SNP and genotyping data for hexaploid wheat and, to a lesser extent, its progenitors and several of its relatives. The site is principally aimed at plant breeders and research scientists who wish to obtain information regarding SNP markers; for example, obtain primers used for their identification or the sequences upon which they are based. The database underpinning the website contains circa one million putative varietal SNPs of which several hundreds of thousands have been experimentally validated on a range of common genotyping platforms. For each SNP marker, the site also hosts the allelic scores for thousands of elite wheat varieties, landrace cultivars, and wheat relatives. Tools are available to help negotiate and visualize the datasets. The website has been designed to be simple and straightforward to use and is completely open access.

Inter-varietal sterility and fertility restoration in Oryza sativa Linn.

This study explored the underlining reproductive factors that cause sterility in rice, using hybrids obtained from crosses among landrace selections and improved varieties. The study was carried out between 2016 and 2018. Nine landrace cultivars and two improved varieties were involved in the hybridization experiment. Among the 17 putative hybrids that were obtained, only 5 were confirmed as true hybrids. Meiotic chromosome studies and pollen studies in the F1, and Mendelian segregation studies for fertility in the F2 were carried out. Some F2 lines were monitored to F3 to ascertain the level of fixation of gene combinations for fertility. The results obtained from the chromosomal studies showed that phenomena such as laggards, precocious movements, formation of multivalents, and unequal segregation to the poles are associated with pollen sterility in all - 5 hybrids, at the F1 and F2 generations. The indehiscence of anthers contributed to infertility due to pollen shortage than the fertility of the pollens themselves. Even though in males, there is a preponderance of male sterility, female sterility is also a phenomenon that is possibly contributing to inter-varietal sterility. The segregational pattern of 13:3 was observed for fertility in the F2 which suggests the inhibition of fertility by a gene in the dominant state. There was the restoration of fertility in many of the lines advanced to the F3 to up to 93 % fertility. It was, therefore, concluded from the study that landraces of rice still hold the key for the rice crop improvement and should therefore be conserved.

Variation in Tuber Dry Matter Content and Starch Pasting Properties of White Guinea Yam (Dioscorea rotundata) Genotypes Grown in Three Agroecologies of NIGERIA

The primary objective of this study was to assess the effects of genotype (G), location (L), and G × L interaction on tuber quality traits (dry matter content and starch pasting parameters) in white Guinea yam (Dioscorea rotundata Poir.). Variability in tuber dry matter and starch pasting properties was examined using 18 advanced breeding lines and two dominant landrace cultivars of white Guinea yam grown in three different agroecological zones (forest‒savanna transition, southern Guinea savanna, and rainforest) in Nigeria. The starch pasting properties were evaluated using a Rapid Visco Analyser. Our results show that the G × L interaction effect was low compared to the genotype and growing location effects on the variability of key starch properties. In addition, the repeatability of trait performance across locations was high and relatively uniform for key traits, suggesting that any of the three locations used in this study can be employed for their evaluation. Furthermore, TDr1100873 had a higher dry matter content than the dominant landrace cultivars (Amula and Meccakusa) but was similar to them in starch pasting properties. Hence, TDr1100873 is considered a suitable variety for future breeding activities.

Impact of Nitrogen Rate in Conventional and Organic Production Systems on Yield and Bread Baking Quality of Soft Red Winter Wheat

Soft red winter wheat (SRW) is characterized by high yield and relatively low protein content. In Kentucky, there is growing demand from local artisan bread bakers for regionally produced flour, requiring production of grain with increased protein content and/or strength. The objective of this two-year field experiment was to evaluate the effect of nitrogen (N) management on five cultivars of winter wheat on yield and bread baking quality traits of modern and landrace SRW cultivars (Triticum aestivum L.). All five cultivars were evaluated using two N application rates in conventional and organic production systems. All traits measured were significantly affected by the agricultural production system and N rate, although plant height and other quality traits varied by study year. Significantly higher yields were achieved in the conventional system at a relatively low N rate (67.2 kg ha−1) in both study years (2017–2019) (p < 0.01). Results were variable by cultivar and a locally bred, high-yielding cultivar (Pembroke 2014) had the highest lactic acid solvent retention capacity score and thousand kernel weight of the cultivars evaluated. In addition, a landrace cultivar (Purple Straw) had the highest grain N and plant height. A French soft wheat, Soissons, had the highest sedimentation value and Pembroke 2016 achieved the highest yield. The findings from this study suggest the possibility of attaining a desirable grain with quality traits of SRW wheat that meets the needs of local bread wheat production in Kentucky through improving the optimization of cultivar selection, N management and specific considerations for conventional and organic systems.

Discovery of a major QTL for root-knot nematode (Meloidogyne incognita) resistance in cultivated sweetpotato (Ipomoea batatas)

Key messageUtilizing a high-density integrated genetic linkage map of hexaploid sweetpotato, we discovered a major dominant QTL for root-knot nematode (RKN) resistance and modeled its effects. This discovery is useful for development of a modern sweetpotato breeding program that utilizes marker-assisted selection and genomic selection approaches for faster genetic gain of RKN resistance.The root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] (RKN) causes significant storage root quality reduction and yields losses in cultivated sweetpotato [Ipomoea batatas (L.) Lam.]. In this study, resistance to RKN was examined in a mapping population consisting of 244 progenies derived from a cross (TB) between ‘Tanzania,’ a predominant African landrace cultivar with resistance to RKN, and ‘Beauregard,’ an RKN susceptible major cultivar in the USA. We performed quantitative trait loci (QTL) analysis using a random-effect QTL mapping model on the TB genetic map. An RKN bioassay incorporating potted cuttings of each genotype was conducted in the greenhouse and replicated five times over a period of 10 weeks. For each replication, each genotype was inoculated with ca. 20,000 RKN eggs, and root-knot galls were counted ~62 days after inoculation. Resistance to RKN in the progeny was highly skewed toward the resistant parent, exhibiting medium to high levels of resistance. We identified one major QTL on linkage group 7, dominant in nature, which explained 58.3% of the phenotypic variation in RKN counts. This work represents a significant step forward in our understanding of the genetic architecture of RKN resistance and sets the stage for future utilization of genomics-assisted breeding in sweetpotato breeding programs.