Creating large EMS populations for functional genomics and breeding in wheat

Wheat germplasm is a fundamental resource for basic research,applied studies,and wheat breeding,which can be enriched normally by several paths,such as collecting natural lines,accumulating breeding lines,and introducing mutagenesis materials.Ethyl methane sulfonate(EMS)is an alkylating agent that can effectively introduce genetic variations in a wide variety of plant species.In this study,we created a million-scale EMS population(MEP)that started with the Chinese wheat cultivars‘Luyan 128’,‘Jimai 38’,‘Jimai 44’,and‘Shannong 30’.In the M1 generation,the MEP had numerous phenotypical variations,such as>3,000 chlorophyll-deficient mutants,2,519 compact spikes,and 1,692 male sterile spikes.There were also rare mutations,including 30 independent tillers each with double heads.Some M1 variations of chlorophyll-deficiency and compact spikes were inheritable,appearing in the M2 or M3 generations.To advance the entire MEP to higher generations,we adopted a single-seed descendent(SSD)approach.All other seed composites of M2 were used to screen other agronomically important traits,such as the tolerance to herbicide quizalofop-P-methyl.The MEP is available for collaborative projects,and provides a valuable toolbox for wheat genetics and breeding for sustainable agriculture.

Artificial selection of the Green Revolution gene Semidwarf 1 is implicated in upland rice breeding

Semidwarf breeding has boosted crop production and is a well-known outcome from the first Green Revolution. The Green Revolution gene Semidwarf 1(SD1), which modulates gibberellic acid(GA) biosynthesis, plays a principal role in determining rice plant height. Mutations in SD1 reduce rice plant height and promote lodging resistance and fertilizer tolerance to increase grain production. The plant height mediated by SD1 also favors grain yield under certain conditions. However, it is not yet known whether the function of SD1 in upland rice promotes adaptation and grain production. In this study, the plant height and grain yield of irrigated and upland rice were comparatively analyzed under paddy and dryland conditions. In response to dryland environments, rice requires a reduction in plant height to cope with water deficits. Upland rice accessions had greater plant heights than their irrigated counterparts under both paddy and dryland conditions, and appropriately reducing plant height could improve adaptability to dryland environments and maintain high grain yield formation. Moreover, upland rice cultivars with thicker stem diameters had stronger lodging resistance, which addresses the lodging problem. Knockout of SD1 in the upland rice cultivar IRAT104 reduced the plant height and grain yield, demonstrating that the adjustment of plant height mediated by SD1 could increase grain production in dryland fields. In addition, an SD1 genetic diversity analysis verified that haplotype variation causes phenotypic variation in plant height. During the breeding history of rice, SD1 allelic mutations were selected from landraces to improve the grain yield of irrigated rice cultivars, and this selection was accompanied by a reduction in plant height. Thus, five known mutant alleles were analyzed to verify that functional SD1 is required for upland rice production. All these results suggest that SD1 might have undergone artificial positive selection in upland rice, which provides further insights concerning greater plant height in upland rice breeding.

Breeding design in wheat by combining the QTL information in a GWAS panel with a general genetic map and computer simulation

A large amount of genome-wide association study(GWAS)panels together with quantitative-trait locus(QTL)information associated with breeding-targeted traits have been described in wheat(Triticum aestivum L.).However,the application of mapping results from a GWAS panel to conventional wheat breeding remains a challenge.In this study,we first report a general genetic map which was constructed from 44 published linkage maps.It permits the estimation of genetic distances between any two genetic loci with physical map positions,thereby unifying the linkage relationships between QTL,genes,and genomic markers from multiple genetic populations.Second,we describe QTL mapping in a wheat GWAS panel of 688 accessions,identifying 77 QTL associated with 12 yield and grain-quality traits.Because these QTL have known physical map positions,they could be mapped onto the general map.Finally,we present a design approach to wheat breeding by using known QTL information and computer simulation.Potential crosses between parents in the GWAS panel may be evaluated by the relative frequency of the target genotype,trait correlations in simulated progeny populations,and genetic gain of selected progenies.It is possible to simultaneously improve yield and grain quality by suitable parental selection,progeny population size,and progeny selection scheme.Applying the design approach will allow identifying the most promising crosses and selection schemes in advance of the field experiment,increasing predictability and efficiency in wheat breeding.

Breeding of a Weak Gluten Wheat Variety Wanmai 788 with High Yield,High Resistance and High Quality

Wanmai 788 is a new wheat variety bred by Nanyang Academy of Agricultural Sciences and approved by Henan Province in 2021.This variety is characterized by high yield,multiple resistance,wide adaptability and high quality weak gluten,and is suitable for planting in wheat areas in the middle and lower reaches of the Yangtze River in the central and southern part of Henan Province.This paper introduces the breeding process,characteristics,yield performance and brief cultivation techniques of Wanmai 788,and discusses the key breeding techniques of the variety.

Breeding and Cultivation Techniques of a New Spring Wheat Variety Kechun 140103

Kechun 140103 is a new spring wheat variety with high and stable yield bred by Keshan Branch of Heilongjiang Academy of Agricultural Sciences.This paper summarizes the breeding process,characteristics,yield performance and cultivation techniques of Kechun 140103,in order to promote the popularization and application of the variety.

Breeding of National Authorized New Wheat Variety Shannong 116 and Supporting Cultivation Technical Measures for High Yield, High Quality and High Efficiency

Shannong 116 is a strong gluten,high yield and multi-resistance wheat variety bred by Shandong Agricultural University,which was approved by the State in 2021 and by Shandong Province in 2022.Shannong 116 combines the excellent characteristics of the female parent(strong gluten,disease resistance and early maturity)and the male parent(high yield,water saving and lodging resistance),with a plant height of 76.9 cm,compact plant type,orderly spike layer and good maturity performance,which is suitable for large-scale promotion and market order planting in Huanghuai wheat area.In this paper,the characteristics of Shannong 116 are analyzed,and cultivation technical measures for high yield,high quality and high efficiency are put forward,in order to provide a technical support for the popularization and application of the variety.

Progress Towards Genetics and Breeding for Minor Genes Based Resistance to Ug99 and Other Rusts in CIMMYT High-Yielding Spring Wheat

Wheat rusts continue to cause significant losses worldwide despite major efforts given to their genetic control. This is due to frequent evolution and selection of virulence in pathogen overcoming the deployed race-specific resistance genes. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach being implemented at CIMMYT is to deploy varieties that posses adult plant resistance （APR） based on combinations of minor, slow rusting genes. When present alone, the APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4 or 5 minor genes usually result in ＂near-immunity＂ or a high level of resistance. Although only a few APR genes are catalogued, various APR QTLs are now known and could lead to further characterization of additional genes. Four characterized genes have pleiotropic effects in conferring partial APR to all 3 rusts and powdery mildew, thus simplifying the task of breeding wheat varieties that are resistant to multiple diseases. Significant progress was made recently in developing high-yielding wheat germplasm that possesses high levels of APR to all three rusts by implementing a Mexico- Kenya shuttle breeding scheme. Parents with APR to Ug99 were hybridized with high-yielding parents that had adequate to high levels of APR to leaf rust and yellow rust. Segregating populations and advanced lines from these crosses were selected under high rust pressures in Mexico （leaf rust and yellow rust） and Kenya （Ug99 stem rust and yellow rust） to identify high- yielding progenies that possess high to adequate APR to all three rusts. International distribution of these high-yielding wheats is underway through CIMMYT intemational yield trials and screening nurseries. It is expected that several wheat varieties with APR to three rusts will be released and grown in various countries in the near-future that will allow determining the durability of resistance.

Study on High-Eefficient Breeding Technology Platform of Dwarf Male-Sterile Wheat

[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile wheat,and the conception of introducing haploid breeding technology into the technological system of high-efficient breeding of dwarf male-sterile wheat was proposed.[Result] Dwarf male-sterile wheat not only retains the properties of total male abortion of Taigu Genetic Sterile Wheat,steady sterility,and high hybrid rate after open pollination,but also has the characteristic of high dwarfing ability of Aibian No.1,becoming a comparatively ideal population modification means.At present,the application of dwarf male-sterile wheat mainly includes germplasm resources platform of population modification by using dwarf male-sterile wheat,technology platform of constructing new high-efficient breeding system by using dwarf male-sterile wheat,and production platform of using dwarf male-sterile wheat to breed new varieties.Through the introduction of haploid breeding into the already established wheat high-efficient breeding system,a new system of high-efficient biological breeding technology of dwarf male-sterile wheat was constructed theoretically.[Conclusion] The study provides references to the further study and application of dwarf male-sterile wheat.

Breeding of New Winter Wheat Variety Nongda No.399

The winter wheat variety Nongda No. 399 was developed by Agriculture and Biotechnology College of China Agricultural University and Hebei Jincheng Seed Corporation Ltd. with the characteristics of high yield, high-resistance and wide adaptation. The variety is suitable for direct seeding in the winter wheat planting area of the central and southern Hebei Province.

An Innovative Project of Wheat Breeding

The objectives of wheat breeding in Sichuan and Chongqing were incon- sistent with the requirements of wheat production in 1980s. The new direction, to breed new wheat variety with high and stable yield, good quality, resistance to dis- eases, tolerance to spike sprouting, large head, white and big grain and outstanding commercial property, was put out in this article based on the development of wheat production, market economy and the needs of people. Depending on the selection and breeding work of Mianyang Institute of Agricultural Sciences for more than 20 years, new wheat varieties Mianyang 25, Mianyang 26, Mianyang 27, Mianyang 28, Mianyang 31, Xikemai 1 and Xikemai 6 were developed successively, which made a great contribution to the wheat breeding wheat breeding and production in SJchuan and even in China and the national food security.

Wheat breeding in northern China: Achievements and technical advances

Common wheat is the major cereal crop that underpins the food safety of China. Both winter wheat and spring wheat are grown on ~24 million ha. This review aims to summarize the current status of wheat production and breeding progress in the northern wheat production areas of the country, and to review recently advanced technologies being applied in wheat breeding, including the use of dwarf-male-sterile(DMS) wheat, speed breeding and specialized wheat breeding SNP chips. Crossing is the initial step in most breeding programs. DMS wheat is a convenient tool for large scale production of hybrid seed. Speed breeding or accelerated generation turnover attempts to reduce the time taken in cultivar development. Several different SNP chips are high-throughput, genome-wide genotyping platforms for breeding and research.

Breeding wheat for resistance to Fusarium head blight in the Global North: China, USA, and Canada

The objective of this paper is to review progress made in wheat breeding for Fusarium head blight(FHB) resistance in China, the United States of America(USA), and Canada. In China,numerous Chinese landraces possessing high levels of FHB resistance were grown before the 1950 s. Later, pyramiding multiple sources of FHB resistance from introduced germplasm such as Mentana and Funo and locally adapted cultivars played a key role in combining satisfactory FHB resistance and high yield potential in commercial cultivars.Sumai 3, a Chinese spring wheat cultivar, became a major source of FHB resistance in the USA and Canada, and contributed to the release of more than 20 modern cultivars used for wheat production, including the leading hard spring wheat cultivars Alsen, Glenn, Barlow and SY Ingmar from North Dakota, Faller and Prosper from Minnesota, and AAC Brandon from Canada. Brazilian wheat cultivar Frontana, T. dicoccoides and other local germplasm provided additional sources of resistance. The FHB resistant cultivars mostly relied on stepwise accumulation of favorable alleles of both genes for FHB resistance and high yield,with marker-assisted selection being a valuable complement to phenotypic selection. With the Chinese Spring reference genome decoded and resistance gene Fhb1 now cloned, new genomic tools such as genomic selection and gene editing will be available to breeders, thus opening new possibilities for development of FHB resistant cultivars.

Distribution and Selective Effects of Vrn-A1,Vrn-B1,and Vrn-D1 Genes in Derivative Varieties from Four Cornerstone Breeding Parents of Wheat in China

Vernalization, the process of a long exposure to low temperature to induce flowering in plants, is essential for plants to adapt to cold winters. The presence of vernalization genes Vrn-A1, -B1, and -D1 in four cornerstone breeding parents of wheat in China （Funo, Mentana, Yanda 1817, and Bima 4） and 322 derivative varieties （mostly winter wheat） from these parents were determined using PCR based molecular method. The frequencies of the VRN-1 genes in these derivative varieties were in order of Vrn-Dl（67.1%）〉 Vrn-Bl（19.6%）〉 Vrn-Al（5.3%）, which are similar as the former conclusion that Vrn-D1 is associated with the latest heading time, Vrn-A1 the earliest, and Vrn-B1 intermediate values. The frequencies of Vrn-Al and Vrn-B1 loci in the derivative varieties from winter wheat zones were higher than that from spring winter zones. Based on the wheat breeding history in China and the fact of non-random distribution of Vrn-A1 and Vrn-B1 in the derivative varieties from the four parents, there could be a strong selective effect on VRN-1 genes in different regions where the derivative varieties were cultivated.

Selection and application of four QTLs for grain protein content in modern wheat cultivars

The grain protein content(GPC)is the key parameter for wheat grain nutritional quality.This study conducted a resampling GWAS analysis using 406 wheat accessions across eight environments,and identified four previously reported GPC QTLs.An analysis of 87 landraces and 259 modern cultivars revealed the loss of superior GPC haplotypes,especially in Chinese cultivars.These haplotypes were preferentially adopted in different agroecological zones and had broad effects on wheat yield and agronomic traits.Most GPC QTLs did not significantly reduce yield,suggesting that high GPC can be achieved without a yield penalty.The results of this study provide a reference for future GPC breeding in wheat using the four identified QTLs.

Wheat breeding model for steady and high yield and early maturation in middle and south Hebei province —Analysis of steady and high yield ability of wheat variety Ji 84-5418

A wheat breeding model for high yield in the middle and south of Hebei Province was developed. Wheat variety Ji 84-5418 has been bred on this model. The analysis results of high-yield and stability indicated that Ji 84-5418 was not only an aggregate of varied excellent characters,but a recombined biotype which could early differentiate spike and develop coordi-nately,and had better self-regulation ability and potential high productivity. Its yield is stable at 6000-8250 kg/ha.

Application of Synthetic Hexaploid Wheat Derived from T.Durum, Ae.taushii in Common Wheat Breeding for FHB Resistance

The F 1 and F 4 plants of 'synthetic hexaploid wheat/common wheat'crosses and part of their parents were inoculated with Fusarium graminearum to evaluate FHB resistance.The results showed tht the scab resistance in the F 1 varied with the synthetic wheat accessions used as crossing parents.In the F 4,some resistant head lines were generated from the crosses,although their parents had different scab resistance levels.It indicated that synthetic hexaploid wheat are useful in wheat breeding for scab resistance.

Breeding and Characteristics of a New Wheat Variety Jike 33

Jike 33 is a new disease-resistant high-yield multi-ear wheat variety with strong gluten bred by Anhui New Century Agricultural Co.,Ltd. in 2001 with Yannong 19 as the female parent and the self-selected Jike 19( variant of Lumai 14) as the male parent. In 2011-2012,the variety participated in the semi-winter wheat regional test in Huaibei area of Anhui Province,and exhibited a yield of 519. 5 kg/667 m^2,which was 7. 83% higher than that of Wanmai 50 as the CK. In the semi-winter wheat regional test in Huaibei area of Anhui Province in 2012-2013,it showed an average yield of 522. 1 kg/667 m^2,which was 14. 5% higher than that of Wanmai 50 as the CK. and in 2013-2014,the variety participated in the semi-winter wheat production test in Anhui Province,and showed an average yield of 589. 30 kg/667 m2,which was 7. 30% higher than that of Wanmai 52 as the CK. Jike 33 was approved by the Anhui Crop Variety Approval Committee in July,2015.

Improvement of Water Use Efficiency in Winter Wheat byBreeding Lines with Low Rate of Water Loss of Excised-Leaves

A study was conducted with the objective of improvement of water use efficiency (WUE) and yield of winter wheat for Lowland Dryland Farming systems through a breeding approach. Various genotypes were screened in 1988 for rate of water loss of excised leaves (RWL) , followed by inter-crossing of diverse parents in 1993. Analysis of the relationship between RWL and yield components and plant traits demonstrated significant differences in RWL among genotypes. Under most circumstances, RWL was correlated negatively with yield and grain weight, and positively with plant height. The results demonstrated a basis for simultaneous selection for high yield and low RWL. It was found that genotypic rank varied with the duration of water loss. Correlation between RWL and yield was reduced by extended water loss duration. Analysis of the genetic variation and segregation of RWL of progenies and the effect of simultaneous screening for RWL and agronomic traits showed that good lines with improved yield and water use performance could be obtained.

Wheat Breeding Strategies under Climate Change based on CERES-Wheat Model

Climate change has inevitably had a negative impact on agricultural production and food security.Crop breeding improvement is an efficient option to adapt to future climate and increase grain production.To study the potential to provide valuable advice for breeding under climate change condition,the crop growth model was used as basis to investigate,the effects of the cultivar genotype parameters of the crop estimation through resource and environment synthesis-wheat(CERES-Wheat)model on yield under different climate scenarios.In this study,solar radiation had a positive effect on the yield of winter wheat,while the effects of daily temperature change conditions on yield were vague,particularly under a change in daily maximum temperature.For the seven cultivar genotype parameters in the CERES-Wheat model,the yield had an approximately linear increasing relationship with kernel number(G1)and kernel size(G2).Vernalization days(P1V)had a fluctuating effect on winter yield without an evident unidirectional tendency.The yield of winter wheat increased with an increase in photoperiodic response(P1D)when P1D values varied from 64.81 to 79.81.Phyllochron interval(PHINT)had a positive impact on the yield of winter wheat.This study presented the potential benefits of the crop growth model to provide directional suggestions for crop breeding.

Effective Approaches to Wheat Improvement in Kazakhstan： Breeding and Conservation Agriculture

International Maize and Wheat Improvement Center （CIMMYT） and Kazakhstan collaborative activities on wheat improvement are focused in the following main areas： （1） wheat germplasm enhancement： Kazakhstan-Siberian Network on Wheat Improvement （KASIB） and Shuttle Breeding ＂Mexico-KASIB＂ Programs; （2） Conservation agriculture （CA） for wheat production and crop diversification. Nineteen breeding programs of Kazakhstan and Russia are united by KASIB Network and Shuttle Breeding. By 2014, more than 15,000 wheat lines and varieties were involved in breeding programs of Kazakhstan and Russia; 10 varieties were developed and released. The KASIB Network and Shuttle Breeding Program were recognized as one of the best example of the effective regional and international cooperation in Kazakhstan and Russia. In the beginning of 2000 CIMMYT, National Agricultural Research System, the Ministry of Agriculture, FAO, World Bank in cooperation with farmers initiated large-scale activities based on CA in Kazakhstan. Due the joint efforts, area under CA-based practices has been increasing from virtually none to an estimated area of 500,000 ha in 2007, 1,200,000 ha in 2008, 2,000,000 ha in 2014 with continued rapid increases in area. Kazakhstan is now included among the top ten countries with the largest areas under no-tillage in the world.