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The stem rust resistance genes Sr24, Sr26, Sr36, and Sr1RSᴬᵐⁱᵍᵒ confer resistance to race TTKSK (= Ug99) of Puccinia graminis f. sp. tritici Pers. (Pgt). A collection of 776 cultivars and breeding lines of wheat (Triticum aestivum L.) from all growing regions of the United States were screened with simple sequence repeat and sequence tagged site markers linked to Sr24, Sr26, Sr36, and Sr1RSᴬᵐⁱᵍᵒ to determine frequencies of these genes in U.S. wheat germplasm. Marker efficacy in predicting the presence of these genes was evaluated via comparison with assayed seedling infection type. Among the lines evaluated, the most predominant gene is Sr24, present in hard winter, hard spring, and soft winter wheat lines. Resistance in soft winter wheat is primarily due to Sr36 The 1RS·1AL rye translocation carrying Sr1RSᴬᵐⁱᵍᵒ is present at equal frequencies in hard winter and soft winter wheat. Utilization of marker-assisted selection for stem rust resistance genes can hasten the development of wheat cultivars resistant to TTKSK and its variants and allow for the development of resistance gene pyramids for more durable stem rust resistance.

Tremendous progress has been made in variety development and host plant resistance to mitigate the impact of Fusarium head blight (FHB) since the disease manifested in the southeastern United States in the early 2000s. Much of this improvement was made possible through the establishment of and recurring support from the US Wheat & Barley Scab Initiative (USWBSI). Since its inception in 1997, the USWBSI has enabled land‐grant institutions to make advances in reducing the annual threat of devastating FHB epidemics. A coordinated field phenotyping effort for annual germplasm screening has become a staple tool for selection in public and private soft red winter wheat (SRWW) breeding programmes. Dedicated efforts of many SRWW breeders to identify and utilize resistance genes from both native and exotic sources provided a strong foundation for improvement. In recent years, implementation of genomics‐enabled breeding has further accelerated genetic gains in FHB resistance. This article reflects on the improvement of FHB resistance in southern SRWW and contextualizes the monumental progress made by collaborative, persistent, and good old‐fashioned cultivar development. [ABSTRACT FROM AUTHOR]

Crown freezing tolerance is the most important factor conferring oat (Avena spp.) winter hardiness. The objective of this study was to identify quantitative trait loci (QTL) for crown freezing tolerance in the 'Kanota' x 'Ogle' recombinant inbred line (RIL) mapping population and to examine their relationship with other winter hardiness traits. One hundred thirty-five RILs were evaluated for crown freezing tolerance in a controlled environment. Previously published molecular marker and linkage map information was used for QTL detection. Seven QTL and four complementary epistatic interactions were identified that accounted for 56% of the phenotypic variation. Ogle contributed alleles for increased crown freezing tolerance at three loci, while Kanota contributed alleles for increased crown freezing tolerance at four loci. All loci where Kanota alleles increased crown freezing tolerance showed complementary epistasis for decreased crown freezing tolerance with the QTL near UMN13. Two of the major QTL identified were in the linkage groups (LG) associated with a reciprocal translocation between chromosomes 7C and 17, which was previously associated with spring growth habit in oat. The results confirm the importance of the chromosomes involved in the reciprocal 7C-17 translocation in controlling winter hardiness component traits.

The reciprocal intergenomic translocation between hexaploid oat (Avena sp.) chromosomes 7C and 17 (T7C-17) has been associated with the division of cultivated oat into A. sativa L. and A. byzantina K. Koch species and differences in crown freezing tolerance and winter field survival. The objectives of this experiment were: (i) to validate the association of T7C-17 with crown freezing tolerance and winter field survival in a population derived from a cross of the non-winter-hardy 'Fulghum' (non-T7C-17) with winter-hardy 'Norline' (T7C-17); (ii) to determine if preferential selection for T7C-17 occurred during inbreeding; and (iii) to examine the association of T7C-17 with the winter hardiness component traits heading date, plant height, and vernalization and photoperiod responses. Crown freezing tolerance and vernalization and photoperiod responses were evaluated in controlled environment studies. Heading date, plant height, and winter field survival were evaluated in field experiments during two seasons. The presence of the translocation was associated with greater crown freezing tolerance, winter field survival, and days to flowering. Translocation status was not associated with vernalization and photoperiod responses or plant height. The T7C-17/non-T7C-17 segregation ratio was 2:1. These results confirmed the importance of T7C17 in conferring winter hardiness traits in winter oat and preferential selection for the translocation during inbreeding.

Hard winter wheat (Triticum aestivum L.) is a major crop in semi‐arid western Kansas. The objective of this research was to develop a hard red winter wheat cultivar for western Kansas with high grain yield potential, good baking quality, and resistance to the important diseases in this region, including Wheat streak mosaic virus, Barley yellow dwarf virus, stripe rust, leaf rust, stem rust, and Hessian fly. 'KS Hamilton' (Reg. no. CV‐1188, PI 699003) hard red winter wheat was developed by the wheat breeding program at the Agricultural Research Center‐Hays, Kansas State University, and released by the Kansas Agricultural Experiment Station in 2020. KS Hamilton was selected from a three‐way cross of KS08HW176‐4//'Bill Brown'/KS08HW61‐2. It was released for the dryland production in western Kansas. KS Hamilton was developed using a modified bulk breeding method. KS Hamilton is an F6‐derived line and was tested in yield trials for 6 yr. KS Hamilton has an intermediate maturity and plant height and an average straw strength. It has moderate tolerance to grain shattering and good winterhardiness. KS Hamilton has high grain yield potential in western Kansas and a good disease resistance package, including resistance to Wheat streak mosaic virus, stem rust, and Hessian fly; moderate resistance to Barley yellow dwarf virus; and intermediate resistance to stripe and leaf rusts. KS Hamilton has an average test weight and an above‐average baking quality. Core Ideas: Hard red winter wheat cultivar 'KS Hamilton' was developed for western Kansas.KS Hamilton has a good disease resistance package for western Kansas.KS Hamilton has above‐average baking quality. [ABSTRACT FROM AUTHOR]

'KS Dallas' (Reg. no. CV‐1173, PI 693934) hard red winter wheat (Triticum aestivum L.) was developed by the wheat breeding program at the Agricultural Research Center–Hays, Kansas State University, and released by the Kansas Agricultural Experiment Station in 2019. KS Dallas was selected from a three‐way cross KS08HW112‐6//TX03A0148/Danby TR made in 2009 at Hays, KS. The objective of this cross was to develop a hard winter wheat cultivar with adaptation to dryland production in western Kansas. KS Dallas was developed using a modified bulk breeding method. KS Dallas is an F6‐derived line and was tested in yield trials across Kansas for 4 yr. KS Dallas has medium maturity, medium height, and a medium‐long coleoptile. It has high grain yield potential in western Kansas and good resistance to the prevalent diseases including Wheat streak mosaic virus and leaf rust. It also has good bread‐making quality. [ABSTRACT FROM AUTHOR]

'KS Western Star' (Reg. no. CV‐1174, PI 693935) hard red winter wheat (Triticum aestivum L.) was developed by the wheat breeding program at the Agricultural Research Center–Hays, Kansas State University, and released by the Kansas Agricultural Experiment Station in 2019. KS Western Star was developed with the objectives to further improve drought tolerance, straw strength, and multiple disease resistance of currently available cultivars for western Kansas. KS Western Star was selected from a single cross 'Byrd'/KS05HW121‐2 made in 2009. KS Western Star was developed as an F6–derived line using a modified bulk breeding method and was evaluated in yield trials from 2014 to 2019. It has medium maturity, medium height, and high grain volume weight, as well as high flour yield and good bread‐making quality. KS Western Star has good adaption to semi‐arid areas in western Kansas with its drought tolerance, stripe rust and leaf rust resistance, and improved lodging resistance. [ABSTRACT FROM AUTHOR]

Little is known about the extent or diversity of resistance in soft red winter wheat ( Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis f.sp. tritici. The soft red winter ( SRW) wheat cultivar ' USG 3555' has effective adult-plant resistance to stripe rust, which was characterized in a population derived from ' USG 3555'/'Neuse'. The mapping population consisted of 99 recombinant inbred lines, which were evaluated for stripe rust infection type ( IT) and severity to race PST-100 in field trials in North Carolina in 2010 and 2011. Genome-wide molecular-marker screenings with 119 simple sequence repeats and 560 Diversity Arrays Technology (DArT) markers were employed to identify quantitative trait loci ( QTL) for stripe rust resistance. QTL on chromosomes 1AS, 4BL and 7D of ' USG 3555' explained 12.8, 73.0 and 13.6% of the variation in stripe rust IT, and 13.5, 72.3 and 10.5% of the variation in stripe rust severity, respectively. Use of these and additional diagnostic markers for these QTL will facilitate the introgression of this source of stripe rust resistance into SRW wheat lines via marker-assisted selection. [ABSTRACT FROM AUTHOR]

The stem rust resistance genes Sr24, Sr26, Sr36, and Sr1RSAmigo confer resistance to race TTKSK (= Ug99) of Puccinia graminis f. sp. tritid Pers. (Pgt). A collection of 776 cultivars and breeding lines of wheat (Triticum aestivum L.) from all growing regions of the United States were screened with simple sequence repeat and sequence tagged site markers linked to Sr24, Sr26, Sr36, and Sr1RSAmigo to determine frequencies of these genes in U.S. wheat germplasm. Marker efficacy in predicting the presence of these genes was evaluated via comparison with assayed seedling infection type. Among the lines evaluated, the most predominant gene is Sr24, present in hard winter, hard spring, and soft winter wheat lines. Resistance in soft winter wheat is primarily due to Sr36. The 1RS·1AL rye translocation carrying Sr1RSAmigo is present at equal frequencies in hard winter and soft winter wheat. Utilization of marker-assisted selection for stem rust resistance genes can hasten the development of wheat cultivars resistant to TTKSK and its variants and allow for the development of resistance gene pyramids for more durable stem rust resistance. [ABSTRACT FROM AUTHOR]

Increasing ambient ozone (O3) concentrations and resurgent rust diseases are two concomitant limiting factors to wheat production worldwide. Breeding resilient wheat cultivars bearing rust resistance and O3 tolerance while maintaining high yield is critical for global food security. This study aims at identifying ozone tolerance among key rust-susceptible wheat genotypes [Rust near-universal susceptible genotypes (RnUS)], as a first step towards achieving this goal. Tested RnUS included seven bread wheat genotypes (Chinese Spring, Line E, Little Club, LMPG 6, McNair 701, Morocco and Thatcher), and one durum wheat line (Rusty). Plants were treated with five O3 concentrations (CF, 50, 70, 90, and 110 ppb), in two O3 exposure systems [continuous stirred tank reactors (CSTR) and outdoor-plant environment chambers (OPEC)], at 21–23 Zadoks decimal growth stage. Visible injury and biomass accumulation rate were used to assess O3 responses. Visible injury data showed consistent order of genotype sensitivity (Thatcher, LMPG 6 > McNair 701, Rusty > Line E, Morocco, Little Club > Chinese Spring). Additionally, leaves at different orders showed differential O3 responses. Biomass accumulation under O3 stress showed similar results for the bread wheat genotypes. However, the durum wheat line "Rusty" had the most O3-sensitive biomass production, providing a contrasting O3 response to the tolerance reported in durum wheat. Chinese Spring was the most tolerant genotype based on both parameters and could be used as a source for O3 tolerance, while sensitive genotypes could be used as sensitive parents in mapping O3 tolerance in bread wheat. The suitability of visible symptoms and biomass responses in high-throughput screening of wheat for O3 tolerance was discussed. The results presented in this research could assist in developing future approaches to accelerate breeding wheat for O3 tolerance using existing breeding materials. [ABSTRACT FROM AUTHOR]