Coffee (Coffea spp.) is an economically important crop widely cultivated in (sub) tropical countries worldwide. Commercial coffee production relies mainly on two related species, namely C. arabica and C. canephora. Due to their perennial growth habit, cultivation practices, and narrow genetic diversity, coffees are constantly exposed to many diseases and pests. Coffee leaf rust (Hemileia vastatrix Berk. et Br.), coffee berry disease (Colletotrichum kahawae Bridge and Waller), and coffee wilt disease (Gibberella xylarioides Heim and Saccas/Fusarium xylarioides) are the top fungal diseases affecting C. arabica and C. canephora production areas worldwide. In many regions, chemical-based control measures are widely used and are the only way to control the diseases. Developing resistant cultivars is one of the prerequisites for increasing sustainable market demand and agriculture. However, desired and required resistance traits are not always available in the gene pool. Furthermore, from other crops it is clear that dominant resistance genes introduced into varieties are not durable because of pathogen variability and the emergence of new races of the different pathogens. Utilization of altered susceptibility genes (S genes) offers a novel and alternative strategy for the breeding of durable and broad-spectrum resistance. The S gene encodes a host factor that facilitates a compatible interaction with the pathogen, and impairment of S genes leads to loss-of-susceptibility. In this review, guidelines for effective identification, characterization, and utilization of dysfunctional S genes are proposed to aid breeding activities in order to introduce durable resistance in Coffea spp. Several candidate S genes likely contributing to the susceptibility of Colletotrichum spp., Fusarium spp., and Meloidogyne spp. are discussed. With the rapid development of genetic engineering techniques, including CRISPR-associated systems, we now have the potential to accelerate the application of S genes to achieve durable resistance in coffee.

Pepper (Capsicum spp.) is an important vegetable crop worldwide with high economic and nutritional value. The Capsicum genus comprises more than 30 species, of which C. annuum, C. chinense, C. baccatum, C. frutescens, and C. pubescens are the five domesticated ones. Anthracnose fruit rot, caused by Colletotrichum spp., is one of the most destructive fungal diseases of pepper. In this review, we compiled up-to-date information from 40 publications on anthracnose resistance in Capsicum species. In total, 375 accessions were described as showing different levels of resistance against Colletotrichum spp. These accessions belonged to different species, including C. annuum (160), C. baccatum (86), C. chacoense (4), C. chinense (90), and C. frutescens (16), as well as 19 accessions of which the species were not reported. High levels of resistance were mainly present in C. baccatum and C. chinense. For some of the resistant accessions, resistance genes or quantitative trait loci (QTL) were reported. Using associated molecular markers, we located 31 QTLs and 17 resistance-related genes in the recently published Capsicum genomes, including C. annuum CM334 version 1.6, C. chinense version 1.2, and C. baccatum version 1.2. Our results could be helpful for making use of some reported accessions in the breeding of pepper cultivars with resistance to anthracnose rot disease.

The coexistence of cereal cyst nematode (CCN) species Heterodera avenae and H. filipjevi, often involving multiple pathotypes, is a limiting factor for wheat production in China. Some of the known genes for resistance to CCN are not effective against both nematode species, hence complicating breeding efforts to develop CCN-resistant wheat cultivars. Here, we demonstrate that the CCN resistance in wheat cultivar Madsen to both Heterodera spp. is controlled by different genetic loci, both of which originated from Aegilops ventricosa. A new quantitative trait locus (QTL), QCre-ma7D, was identified and localized in a 3.77-Mb genomic region on chromosome arm 7DL, which confers resistance to H. filipjevi. QCre-ma2A on chromosome arm 2AS corresponds to CCN resistance gene Cre5 and confers resistance to H. avenae. This QTL is a new locus on chromosome arm 7DL and is designated Cre9. Three Kompetitive allele-specific PCR markers (BS00150072, BS00021745, and BS00154302) were developed for molecular marker-assisted selection of Cre9 and locally adapted wheat lines with resistance to both nematode species were developed. QCre-ma2A on chromosome arm 2AS corresponds to CCN resistance gene Cre5 and confers resistance to H. avenae. The identification of different loci underlying resistance to H. filipjevi and H. avenae and the development of adapted resistant entries will facilitate breeding of wheat cultivars that are resistant to these devastating nematodes in China.

Triticale (× Triticosecale Wittmack) is a valuable dual-purpose crop due to its adaptability to marginal environments and its potential for both high-quality grain and forage production. However, a comprehensive evaluation of its forage quality characteristics and agronomic performances is still needed. This study evaluated the grain and forage yield potentials and nutritional compositions of 11 triticale genotypes over two consecutive years in a semi-arid region located in Shanxi province, China. Forage quality was assessed using several key parameters, including nutrient composition, fiber digestibility, mineral content, and energy density, while grain quality parameters, including nutrient composition as well as carbohydrate and fiber characteristics, were also analyzed. Significant genetic variation was observed in these traits, indicating the influence of genotype–environment interactions on these traits. The tested genotypes exhibited grain yields ranging from 4.83 to 6.92 t ha⁻¹ and fresh forage biomass yields between 20.06 and 29.78 t ha⁻¹, demonstrating their potential for sustainable forage and grain production under semi-arid conditions. Genotypes from our breeding programs, including Shengnongsicao 1 and Jinsicao 1, demonstrated superior adaptability, maintaining stable forage and grain yield potentials under adverse conditions. Their favorable nutritional characteristics further enhance their suitability for semi-arid livestock systems. High levels of essential minerals, particularly calcium and potassium, further enhanced the nutritional value of these genotypes. These results provide valuable insights for triticale breeding programs and suggest triticale’s potential as a reliable crop in semi-arid regions, where maximizing land productivity is essential.

Wide hybridization between wheat and wild relatives such as Thinopyrum intermedium is important for broadening genetic diversity and improving disease resistance in wheat. We developed 30 wheat-Th. intermedium derivatives. Here, we report assessments of their resistance to different pathogens including cereal cyst nematode (CCN; Heterodera spp.), Puccinia striiformis f. tritici Erikss. causing stripe rust, and Blumeria graminis f. tritici (DC.) Speer inciting powdery mildew. Under natural field infection, all the wheat-Th. intermedium lines were resistant to at least one of the pathogens, and four lines were resistant to multiple pathogens. Twenty-nine of 30 tested lines exhibited resistance to H. avenae, a dominant CCN species in wheat fields. Twenty-four lines were resistant to H. filipjevi, an emerging threat to wheat production. Tests of phenotypic responses in the naturally infected field nurseries identified six stripe rust-resistant lines and 13 powdery mildew-resistant lines. Mitotic observation demonstrated that these newly developed wheat-Th. intermedium derivatives included not only octoploid but also chromosome addition, substitution, and translocation lines. Chromosome compositions of the four lines resistant to multiple pathogens were analyzed by genomic in situ hybridization and fluorescence in situ hybridization. The octoploid lines Zhong 10-68 and Zhong 10-117 carried both intact Th. intermedium chromosomes and translocated chromosomes. Line Zhong 10-149 had 42 wheat chromosomes and two wheat ditelosomes plus a pair of T3BS·J translocated chromosomes. Line Zhong 10-160 carried 41 wheat chromosomes plus one pair of the J genome chromosomes of Th. intermedium. The multiple disease-resistant wheat-Th. intermedium derivatives, especially lines with chromosome counts close to that of common wheat, provide valuable materials for wheat resistance breeding programs.

Elymus sibiricus, valued for its perennial nature, broad adaptability, strong cold tolerance, and high economic value in forage production, plays a crucial role in combating grassland degradation, desertification, and salinization. Using morphological and cytogenetic methods, this study evaluated the cold tolerance, post-harvest regeneration capacity, and perennial characteristics of the E. sibiricus accession 20HSC-Z9 in the Harbin region of China from 2020 to 2023. This accession exhibited a germination rate of over 90% and a 100% green-up rate, with purple coleoptiles indicating its strong cold tolerance. Over the three growing seasons, 20HSC-Z9 maintained stable green-up and regeneration rates, confirming its perennial nature. Morphologically, 20HSC-Z9 had an average tiller count ranging from 56 to 74, similar to that of the control accession 20HSC-ES, and its plant height was significantly lower than that of 20HSC-IWG. Furthermore, 20HSC-Z9 produced over 100 grains per spike, with a seed setting rate exceeding 90%, and a thousand-grain weight comparable to that of 20HSC-IWG. The grain protein content of 20HSC-Z9 reached a maximum of 21.19%, greater than that of the control accessions (15.6% and 18.5%). Chromosome composition analysis, using sequential multicolor genomic in situ hybridization and multicolor fluorescence in situ hybridization, confirmed the StStHH genomic constitution of 20HSC-Z9 and revealed translocations between the St and H subgenome chromosomes. These results suggest that 20HSC-Z9 has significant potential as a new perennial forage grass germplasm for cold regions, suitable for further domestication and breeding efforts.