Important Wheat Research Articles

Nove informacije o biljnoj privredi Kelta u severnoj Srbiji

The archaeobotanical research of the macrobiotic remains from archaeological sites provides a valuable insight into the plant economy of the continental Celtic (Gaulish or Galatian) tribe of Scordisci, which lived around the rivers of Sava, Drava and Danube during the last three centuries before Christ. The field crop production of Scordisci was based upon cereals, grain legumes and oil crops. The importance of spelt wheat (Triticum spelta L.) in the everyday diets of Scordisci has been underestimated so far. Recent researches proved the presence of Byzantine oat (Avena byzantina K. Koch) at the Celtic tilths in the northern Balkans. Cereals were stored in mud-plastered granary baskets. The spectrum of grain legumes is as diverse as that of cereals. The latest analyses expand the list of oil plants with a new species-dragon's head (Lallemantia iberica (M.Bieb.) Fisch. & C.A.Mey.). There is also the first evidence of a beer production facility in one of the Scordisci oppida, Čarnok.

Soil-specific drought sensitivity of Hungarian terroirs based on yield reactions of arable crops

The hypothetical climate change and the stress influences caused by the increasingly frequent found meteorological extremities affect the fertility of soils in even more degree. During our soil-climate sensitivity researches, the expression of the drought sensitivity as a stress influence, evolved as a result of lack of precipitation in soil fertility was studied. During our work, effects of increasing droughts of last decades were investigated through the yield results of the three most important crops, winter wheat (Triticum aestivum L.), corn (Zea mays L.), and sunflower (Helianthus annuus L.), based on the area rate in the Hungarian sowing structure, in relation to the natural geographical microregions and fertility of sites. For the examinations, yield data of the National Pedological and Crop Production Database (NPCPD) were used. The database contains complex plot-level crop production and soil information for 5 years (1985–1989). The examination results prove the considerable drought sensitivity of that lands, where soil types with high sand or clay content can be found. The mainly exposed microregions for the effects of drought are, e.g., the Dorozsma-Majsa Sand Ridge, Kerka Riverscape, Dévaványa Plain etc., while less sensitive sites are e.g. the Enying Ridge, Tolnai-Sárköz, Nógrád Basin etc.

Prevalence of Yellow Rust at Minjar, Basonawarena and Moretenajihur District of North Shewa Zone, Ethiopia

Stripe (Yellow) rust caused by <i>Puccinia striiformis</i> f.sp. <i>tritici</i> (<i>Pst</i>) is important wheat diseases causing serious damage on cultivated wheat variety. The wheat yellow rust assessment was conducted in the main rainy season of 2018/19 at Minjar, Basonawarena and Moretnajihur using “Z” method of diseases assessment. Disease and agro-eological data were recorded. The disease was prevalent at all districts by varying incidence and severity ranges. The highest Yr prevalence 100% was recorded at Moretenajihur districts: conversely; the lowest prevalence percentage 16.67% was at Minjar district. The highest severity and incidence of yellow rust 40-100% and 10-40%, respectively was recorded at Moretenajihur with MS to S reaction; while the lowest severity and incidence (0-15% and 0-5%) respectively was recorded at Minjar with reaction of MS. Factors such as wheat variety, growth stage and agro-ecological variations have contributions for the distributions and occurrence of yellow rust. Highest yellow rust incidence ranges 100% S on field cultivated with bread wheat on variety kakaba and Kubsa at growth stage of Milk to matured stage. Local cultivar has shown lowest incidence and severity percentage with moderately susceptible responses than improved varieties.

Proximate, Chemical and Functional Properties of Wheat, Soy and Moringa Leaf Composite Flours

The study presents the effect of utilizing wheat, soy and moringa leaf flour and quality analysis of the flour. The composite flour was prepared using refined wheat flour, soy flour and moringa leaf flour. Four composite flour, compositions were formulated such as 100% wheat flour (control) designated as sample A. Sample B consisted of 75% wheat, 20% soybean and 5% moringa leaf. Sample C consisted of 70% wheat, 20% soybean and 10% moringa leaf. Sample D was 65% wheat, 20% soybean and 15% moringa leaf. Sample E was 60% wheat, 20% soybean and 20% moringa leaf, respectively. Proximate, chemical, and functional properties of wheat, soy and moringa leaf flours were studied in composite flour variation and preparations. The present study highlighted the nutrients enrichment of flour on incorporation of soy and moringa leaf. Relevant statistical tests were done to analyse the significance of means for all tested parameters. Composite flour composition with 20% soybean was identified to produce optimal nutrient, mineral quality and yield. The addition of soybean and moringa flour in baked products has been shown in this study to improve the nutrition and health benefits of the body. It also serves as a good cut on the cost of wheat importation in communities with supply challenges.

Do future markets protect the spot markets in developing countries? The case of the Egyptian wheat market

Egypt is considered a net wheat importer, with the Egyptian market being vulnerable to future wheat markets because of the effect future market price discovery can have on the stability of spot prices. This study assesses the relationship between Egyptian wheat spot prices and future wheat prices in Paris (MATIF) and USA (CBOT). Markov switching-vector error correction methods are used to estimate two regimes by splitting the sample into high and low volatility regimes. This study also examines the dynamic conditional correlation between the prices considered using the asymmetric DCC-GARCH. Results suggest a high volatility regime observed, especially during the extreme market events of the food crisis in 2007-08 and 2010 and following the two revolutions in Egypt in 2011 and 2013 and the time of the economic reform in 2016. This leads to an unstable market and negative impacts on consumers’ welfare and food affordability, meaning that futures markets failed to hedge spot wheat market against price volatility. In addition, results from impulse response functions indicate that a 1% shock in futures markets will lead to a positive shock in the wheat spot market, while for the low volatility regime no significant effect.

Export Oriented Agriculture in the Agri-History of India

India’s agricultural research has the main emphasis on food grains production and rightly so because of short food supply and dependence on import of wheat from USA. Now the country has become self-sufficient in food and its research needs re-orientation because, most farmers remain below poverty line. Some attention was paid to traditional commercial crops such as cotton, sugarcane and potato for raising the level of farmers above poverty lines, but when they had surplus in production of these crops, they could not export these, because it was difficult to compete in the international market. Nevertheless, there are some herbal crops, where it can compete fairly well in the international export. For example, it has global monopoly in isabgol / psyllium and is topmost exporter in turmeric and only next to China in ginger. However, to maintain these positions in herbal crops in the international export market, India needs to invest a little more in agricultural, scientific and marketing research. Agricultural research is needed to develop high yielding varieties and their agronomy with higher content of main active chemicals and of course market research for new countries to export. Government of India needs to identify more such crops, the areas where they are grown and provide necessary research, processing facilities and procurement at pre-fixed price to facilitate their production and export. This will bring home the much needed foreign exchange and certainly raise the status of some farmers above the poverty line.

Farmers' Preferences of Improved Wheat Varieties in Wheat Subsector Kailali, Nepal

Kailali is the second highest district regarding wheat production and area coverage. A study was carried out in the Kailali district for preference of farmers on different wheat varieties that were being cultivated in the district. The objective of the study was to assess farmers’ preference and perception on the different improved wheat varieties in the area. Five commonly grown wheat varieties and seventeen important wheat varietal traits were selected through focus group discussion, key informant interview and preliminary survey. Sixty households were selected for face-to-face personal interview, twelve for each selected variety, at random from Ghodaghodi Municipality, Gauriganga Municipality and Kailari Rural Municipality of Kailali. The weightage of the seventeen selected traits were determined using an online survey conducted among individuals from different designation with the agricultural background who were well known about wheat cultivation practices in Kailali district. Yield, flour quality and tillering were found to be the trait of higher weightage and stem thickness was the trait of lowest weightage. The preferences of the farmers were measured using wheat preference index (WPI). The varieties Vijay, NL-971, HD-2967, Gautam and Aditya were ranked as I, II, III, IV and V respectively. The incorporation of farmers' preferred traits in future wheat varieties would increase the likelihood of adoption of the varieties. Similarly, proper participatory field trial of new improved wheat varieties would also help in the selection of the suitable varieties in the area concerning the farmers’ criteria of selection.&#x0D; Int. J. Appl. Sci. Biotechnol. Vol 8(4): 432-436

Spatial Agglomeration Pattern and Driving Factors of Grain Production in China since the Reform and Opening Up

Since the reform and opening up, regional imbalances in the development of market economy and urbanization have significantly changed the spatial agglomeration pattern of grain production (GP) in China. To characterize GP by the yield, we used the gravity center (GC) and standard deviation ellipse (SDE) to investigate the evolution characteristics of the spatial agglomeration pattern of GP and its three major crops with wheat, maize and rice in China, then establish a spatial econometric model to explore the natural and socioeconomic drivers of GP at the national level, at different crops and at different regions. The research results indicate that the GC of GP gradually shifts and expands to the northeast and presents a spatial distribution pattern in a “northeast–southwest” direction. The GC of wheat production mainly expands upwards in the east–west direction. The GC of maize production shifts in a direction that is more consistent with grain production, and there is an expansion trend in the east–west direction, while the GC of rice production has the largest north–south span, and continues to expand upward to the north by the east. The status of grain production in Northeast China and Northwest China is rising and the importance of grain production in the Southeast coastal areas are decreasing. The importance of wheat and corn production in North China continues to strengthen, and Northeast China is becoming more important for rice production, but the middle and lower reaches of the Yangtze River are still important rice producing regions. Changes in GP with significant spatial dependence are jointly affected by many factors, such as natural and socio-economic factors, and there are obvious differences among different food crops and different division regions, with the most prominent positive effects being the multiple crop index (MCI), arable land per capita (AL) and agricultural mechanization (MECH), while economic growth and urbanization are significantly negative.

Assessment and potential-site determination of a wheat straw power plant by Aspen Plus and multi-criteria GIS model.

Wheat is one of the most important crops worldwide. Mexicali, Baja California, is an important wheat producer in Mexico with an average production of 507,543 t. Wheat straw is generated as a residue which could be used for different purposes such as bioenergy, heat and power generation. In this work, an assessment and potential site determination of a biomass power plant operating with wheat straw as fuel was performed. Aspen Plus was used to evaluate a plant capacity of at least 10 MW considering the physicochemical properties and an higher heating value of 14.86 MJ kg-1 of the wheat straw from the region. The combustion produced 39.76 MW, and the overall plant efficiency was 25.52%. The development of the multi-criteria geographic information system model allowed us to assess and analyse four factors and three restrictions to determine the potential site for the biomass power plant. The factors were raw material, wheat crops, electric transmission lines, paths and roads, water canals and aqueducts, while the restrictions were localities, Ramsar sites and faults. The biomass power plant is technically and geographically feasible. The geographical coordinates of the potential site of the biomass power plant that fulfils all the criteria are 32°29'29.72″N and 115°15'39.45″W.

Pyramiding of High Grain Weight With Stripe Rust and Leaf Rust Resistance in Elite Indian Wheat Cultivar Using a Combination of Marker Assisted and Phenotypic Selection.

Wheat (Triticum aestivum L.) is an important cereal crop globally as well as in India and yield improvement programs encounter a strong impediment from ever-evolving rust pathogens. Hence, durable rust resistance is always a priority trait for wheat breeders globally. Grain weight, represented as thousand grain weight (TGW), is the most important yield-contributing trait in wheat. In the present study high TGW has been transferred into two elite Indian wheat cultivars PBW343 and PBW550 from a high TGW genotype, Rye selection 111, selected from local germplasm. In the background of PBW343 and PBW550, an increase in TGW upto 27.34 and 18% was observed, respectively (with respect to recipient parents), through conventional backcross breeding with phenotypic selections in 3 years replicated RBD trials. Resistance to leaf rust and stripe rust has been incorporated in the high TGW version of PBW550 through marker assisted pyramiding of stripe rust resistance gene Yr15 using marker Xuhw302, and a pair of linked leaf rust and stripe rust resistance genes Lr57-Yr40 using marker Ta5DS-2754099_kasp23. Improved versions of PBW550 with increased TGW ranging from 45.0 to 46.2 g (up to a 9% increase) and stacked genes for stripe and leaf rust resistance have been developed. This study serves as proof of utilizing conventional breeding and phenotypic selection combined with modern marker assisted selection in improvement of important wheat cultivars as a symbiont of conventional and moderan techniques.

Embryo-Endosperm Interaction and Its Agronomic Relevance to Rice Quality.

Embryo-endosperm interaction is the dominant process controlling grain filling, thus being crucial for yield and quality formation of the three most important cereals worldwide, rice, wheat, and maize. Fundamental science of functional genomics has uncovered several key genetic programs for embryo and endosperm development, but the interaction or communication between the two tissues is largely elusive. Further, the significance of this interaction for grain filling remains open. This review starts with the morphological and developmental aspects of rice grain, providing a spatial and temporal context. Then, it offers a comprehensive and integrative view of this intercompartmental interaction, focusing on (i) apoplastic nutrient flow from endosperm to the developing embryo, (ii) dependence of embryo development on endosperm, (iii) regulation of endosperm development by embryo, and (iv) bidirectional dialogues between embryo and endosperm. From perspective of embryo-endosperm interaction, the mechanisms underlying the complex quality traits are explored, with grain chalkiness as an example. The review ends with three open questions with scientific and agronomic importance that should be addressed in the future. Notably, current knowledge and future prospects of this hot research topic are reviewed from a viewpoint of crop physiology, which should be helpful for bridging the knowledge gap between the fundamental plant sciences and the practical technologies.

Detection and quantification of airborne spores from six important wheat fungal pathogens in southern Alberta

Wheat is affected by many fungal diseases that can cause severe yield and quality losses. Disease prediction models generally employ weather data to estimate potential for infection to determine timing for fungicide applications, but these models fail to account for the presence and quantity of pathogen inoculum. This study adapted highly specific qPCR primers to identify and quantify, in real-time, inoculum present in air for the six most important wheat pathogens in Canada. Fungal spores were collected using either Burkard spore collectors and quantified using qPCR or microscope slides covered with adhesive tape and identified and quantified using microscopy. Samples were collected from seven different sites in southern Alberta throughout the 2015–2017 growing seasons. The results demonstrated that qPCR can reliably identify and quantify spores from Puccinia striiformis f. sp. tritici, P. triticina, P. graminis f. sp. tritici, Blumeria graminis f. sp. tritici, Pyrenophora tritici-repentis, and Fusarium graminearum. The limits of detection of DNA for primer pairs in singleplex tests ranged from 0.0001 ng for P. graminis to 0.001 ng for P. tritici-repentis, which corresponded to approximately 3 spores for P. tritici-repentis and F. graminearum and 1 spore for the other pathogens. Conversely, microscopy permitted identification of rusts to the genus but not to the species level and was ineffective in quantification of the remainder of the wheat pathogens. This study will contribute to the development of a fast and reliable forecasting system that will enable identification and quantification of airborne pathogens in real-time before initial disease symptoms appear.

Genetic mapping of male sterility and pollen fertility QTLs in triticale with sterilizing Triticum timopheevii cytoplasm

Cytoplasmic male sterility (CMS) phenomenon is widely exploited in commercial hybrid seed production in economically important crop species, including rye, wheat, maize, rice, sorghum, cotton, sugar beets, and many vegetables. Although some commercial successes, little is known about QTLs responsible for the trait in case of triticale with sterilizing Triticum timopheevii (Tt) cytoplasm. Recombinant inbred line (RIL) F6 mapping population encompassing 182 individuals derived from the cross of individual plants representing the HT352 line and cv Borwo was employed for genetic map construction using SNP markers and identification of QTLs conferring pollen sterility in triticale with CMS Tt. The phenotypes of the F1 lines resulting from crossing of the HT352 (Tt) with HT352 (maintainer) × Borwo were determined by assessing the number of the F2 seeds per spike. A genetic map with 21 linkage groups encompasses 29,737 markers and spanned over the distance of 2549 cM. Composite (CIM) and multiple (MIM) interval mappings delivered comparable results. Single QTLs mapped to the 1A, 1B, 2A, 2R, 3B, 3R, 4B, and 5B chromosomes, whereas the 5R and 6B chromosomes shared 3 and 2 QTLs, respectively. The QTLs with the highest LOD score mapped to the 5R, 3R, 1B, and 4B chromosomes; however, the QRft-5R.3 has the highest explained variance of the trait.

Standard Estimating for the Quantity of Wheat Imports Required to Achieve Food Security in Egypt

The issue of food and food security is one of the most important strategic issues on the international scene, because of its political, economic and social dimensions, there is a strong relationship between the food security and the national security of any society, and the agricultural development strategy in Egypt has aimed at improving self-sufficiency and reducing the food gap from strategic food crops. The aim of the project is to provide a better level of food security, and wheat is the first strategic crop in Egypt, and given the vulnerability of production areas to inappropriate climatic conditions, especially in the circumstances that are now sweeping the world to the Covid-19 pandemic, this could exacerbate the food problem and increase food prices .It is therefore necessary to address this problem by maintaining a strategic wheat stock that will be sufficient for consumption needs for at least six months as food security. Through studying the current situation of food security, it was found that the quantity of strategic wheat stocks amounted to about 2221.5 thousand tons, enough for local consumption for 63 days, and the value of the food security factor during the study period was 0.173. According to the unconventional method of analysis known as the Tobit model to measure the impact of economic factors on the food security factor of wheat, the most important of which was local production and consumption and the amount of Egyptian imports of wheat, and the significance of the effect of these factors has been proven, in addition to matching the regression coefficients signs with the independent variables of economic theory assumptions, and to achieve a level of 0.5 For food security laboratories, an amount of 15,197,156,000 tons of wheat are required for each of them in 2023 and 2025, respectively. But in light of achieving the full level of food security laboratories, it requires importing a quantity of wheat amounting to 22046 and 22468 thousand tons each in 2023 and 2025 respectively. And the research recommends the necessity of increasing the food security coefficient of wheat from 0.173 to 0.5 in order to create a strategic stockpile enough for local consumption for at least six months, by taking some policies, the most important of which are: 1- Expanding wheat production in light of the increase in the cultivated area until it reaches approximately 4 million acres. 2- Rationalizing wheat consumption in urban and rural areas. Managing the resources needed to import wheat to achieve the targeted levels of food security laboratories in 2023 and 2024

Biocontrol Agents for Controlling Wheat Root Rot Disease under Greenhouse Conditions

Background: The most important wheat diseases that caused by soil-borne fungi are the root-rot disease. The current investigation conducted with evaluation the efficacy of some bioagents, Bacillus subtilis, Pseudomonas fluorescens, Azospirillum brasilense, Trichoderma harzianum, commercial bioagent (Planta guard) and chitosan against the causal pathogenic organisms of wheat root rot disease under greenhouse conditions. Methods: Wheat seedlings infected with root rot disease were subjected to the causal fungal isolation trails. In greenhouse, wheat grains were sown individually in pots containing artificially infested soil with the pathogenic fungi R. solani or F. graminearum. Furthermore, the tested bioagents and the fungicide Topsin-M 70 were applied to the infested soil before sowing. Result: The isolated fungi were R. solani or F. graminearum had proved their pathogenic ability to induce root rot disease of wheat. In pot experiment, all applied treatments affect root rot incidence of grown wheat seedlings in artificially infested soils with disease incidents. In infested soils with root rot incidents, bacterial bioagents reduced root rot incidence by 84.5-93.6% and 28.4- 35.3% 66.6, respectively and by 43.7% for T. harzianum. Moderate effect was obtained by chitosan and planta guard treatments in soil infested with either pathogenic fungi.

BREAD PRODUCED FROM COMPOSITE FLOURS USING Saccharomyces cerevisiae ISOLATED FROM LOCAL FERMENTED BEVERAGE (BURKUTU)

Composite flour/bread technology is an important area to be properly harnessed in food industries to help reduce the cost of wheat importation in Nigeria. In this study, bread produced from composite flours using Saccharomyces cerevisiae isolated from local fermented beverage (Burkutu) was investigated. Sugar fermentation, carbohydrate utilization and ethanol tolerance tests were carried out in identifying and characterizing the yeast isolates. Composite breads were produced from Wheat Flour (WF) (100%) and its blends with Rice Flour (RF) (40%), Plantain Flour (PF) (40%) and Cassava Flour (CF) (40%) using the straight dough method. The yeast survived in 25% glucose and 15% ethanol, suggesting its usefulness in industrial application. Loaf weights and loaf volumes of the composite bread samples ranged from 318.4 - 355.7 g, and 420.6 - 457.3 mL respectively, with 100% Wheat Bread ranking highest while Composite rice bread the least, using a significant difference of P&lt;0.05. The total yeast count recorded after 4 days showed 0.25 x 10-3 CFU/mL (100% W bread), 0.40 x 10-3 CFU/mL (W/R (bread), 0.21 x 10-3CFU/mL (W/P bread) and 0.32 x 10-3CFU/mL for W/C bread. Sensory assessment revealed that there was no significant difference (P&gt;0.05) in the bread samples analysed. Shelf life assessment of the bread samples at room temperature (26±1oC) within the first three days revealed no microbial growth/cell count. Bread produced from the incorporation of cassava with wheat flour was found to be acceptable, with insignificant variation when compared to bread made with 100% wheat flour.

Screening stored wheat beetles for reproductive parasitic endosymbionts in central Turkey

Stored-product pest insects cause significant loss in stored wheat worldwide. In Turkey, an important wheat producer and historic centre of wheat domestication, almost 60 stored-product pest insects have been reported so far, most of them being coleopteran species. Using reproductive parasitic endosymbionts (RPEs) is a promising recent approach among control methods alternative to insecticides. For planning and studying pest management with these bacteria, first of all, their presence in the natural pest populations should be investigated. The present study focused on screening the RPEs in Central Anatolian stored wheat pests. We collected pests in granaries in Kırşehir province and identified 10 coleopteran species both morphologically and genetically; namely, Ahasverus advena, Cryptolestes ferrugineus, C. pusillus, Carpophilus obsoletus, Oryzaephilus surinamensis, Rhyzopertha dominica, Sitophilus granarius, S. oryzae, S. zeamais, and Tribolium castaneum. In these pests, we screened the most commonly studied RPEs worldwide, Arsenophonus, Cardinium, Fritschea, Hamiltonella, Rickettsia, Spiroplasma, and Wolbachia, by using specific genetic primers. As a result, we detected RPE presence in almost all sampling localities visited. The RPEs that we found were Rickettsia, Spiroplasma, and Wolbachia. We found no infection caused by Arsenophonus, Cardinium, Fritschea, nor Hamiltonella. Rickettsia presence was only in S. granarius populations, whereas Spiroplasma and Wolbachia presence were not species specific. 22% of all sampled beetle individuals were Wolbachia positive. The highest detection rate per granary was that of Spiroplasma (80%). Wolbachia and Spiroplasma were the most frequently detected RPEs per insect species. We also found several cases of coinfections. This study is the first attempt to screen stored-product pests for seven RPEs together.

Assessing the Response of Satellite Solar-Induced Chlorophyll Fluorescence and NDVI to Impacts of Heat Waves on Winter Wheat in the North China Plain

Global warming has increased the chance of concurrent extreme climate events (weather or climate events that are rare within their statistical reference distributions in a particular place, such as heat waves, floods, and droughts). Crops grow best within specific temperature intervals, and excessive heat is detrimental to the physiological processes of crops and eventually affects yield levels. Analysing historical changes in concurrent extreme high temperatures is critical to preparing for and mitigating the negative effects of climatic change. The North China Plain (NCP) is the most important wheat production area in China. In this study, the spatiotemporal variations in temperature and heat wave trends in the NCP were analysed. Furthermore, we examined the potential of solar-induced chlorophyll fluorescence (SIF) to capture the influence of heat wave impacts on wheat crops in the NCP by comparing satellite remote sensing data of SIF and normalized difference vegetation index (NDVI) and validated ground-based yield data. The results indicate that temperatures and the number of heat wave days in the study region all show increasing trends, especially daily minimum temperature, which has increased by 0.38°C per decade for the past 30 years. Spatially, the southern NCP has suffered greater increasing-temperature trends and more heat wave days than the northern region. Regarding the response of SIF and NDVI to heat waves, SIF can better capture wheat yield decline due to heat waves compared to NDVI; thus, the SIF result indicated more sensitivity to heat waves compared to NDVI.

Genetic diversity in historical and modern wheat varieties of the U.S. Pacific Northwest

AbstractLoss of crop genetic diversity due to modern plant breeding is an enduring global concern. The U.S. Pacific Northwest (PNW) is an important wheat (Triticum aestivum L.)‐producing region. We examined population structure and changes in genomic‐level and agroecosystem‐level genetic diversity of PNW wheat over the past 120 yr. Wheat varieties were slightly structured by spring and winter growth habit, but not by geographic origin or period of variety release. At the genomic level, we did not find long‐term shifts in gene diversity in either spring or winter wheat, but fluctuations were significant within market classes and within the most widely grown spring and winter varieties. Diversity in hard red spring (HRS) wheat peaked in 1970–1999 and since dropped below the level of varieties before 1930. Hard red winter (HRW) in 2000–2019 is more diverse than before 1930, whereas soft white spring (SWS) and soft white winter (SWW) are at the same level of diversity in 2000–2019 as they were before 1930. The most widely grown spring varieties had the lowest diversity in 1930–1969, whereas the most widely grown winter varieties had the lowest diversity in 2000–2019. At the agroecosystem level, Simpson's index of diversity (1 − D) has been on a rising trend since the 1990s as the dominance of acreages by a few varieties has become less common. Cultivation of multiple market classes and periodic incorporation of new germplasm by breeding programs have been able to maintain the quantitative level of genetic diversity in PNW wheat over time.

The wheat receptor-like cytoplasmic kinase TaRLCK1B is required for host immune response to the necrotrophic pathogen Rhizoctonia cerealis

Receptor-like cytoplasmic kinases (RLCKs) represent a large family of proteins in plants. In Arabidopsis and rice, several RLCKs in subfamily VII (RLCKs-VII) have been implicated in pathogen-associated molecular pattern-triggered immunity and basal resistance against bacterial and fungal pathogens. However, little is known about roles of RLCKs-VII of the important crop common wheat (Triticum aestivum) in immune responses. Here, we isolated a RLCK-VII-encoding gene from wheat, designated as TaRLCK1B, and investigated its role in host immune response to infection of a necrotrophic fungus Rhizoctonia cerealis that is a major pathogen of sharp eyespot, a destructive disease of wheat. RNA-sequencing and RT-qPCR analyses showed that transcriptional level of TaRLCK1B was significantly higher in sharp eyespot-resistant wheat cultivars than in susceptible wheat cultivars. The gene transcription was rapidly and markedly elevated in the resistant wheat cultivars by R. cerealis infection. The TaRLCK1B protein was closely related to OsRLCK176, a rice resistance-related RLCKs-VII, with 84.03% identity. Virus-induced gene silencing plus wheat response to R. cerealis assay results indicated that silencing of TaRLCK1 impaired resistance to R. cerealis. Meantime, silencing of TaRLCK1 significantly elevated both the content of H2O2 (a major kind of reactive oxygen species, ROS) and the transcriptional level of the ROS-generating enzyme-encoding gene RBOH, but repressed the expression of the ROS-scavenging enzyme-encoding gene CAT1 at 18 hours after inoculation (hai) with R. cerealis. Taken together, these data suggested that TaRLCK1B was required for the early immune response of wheat to R. cerealis through modulating ROS signaling in wheat.