Molecular Breeding最新文献

Heterosis is often exploited to produce high-yielding crops with better performance than their inbred counterparts. Commercial rice breeding has made use of this phenomenon as well, primarily through the use of cytoplasmic male sterility (CMS) and environment-sensitive genic male sterility (EGMS). However, a limited understanding of the molecular and physiological basis of heterosis prevents researchers from harnessing the full potential of hybrid breeding. This review examines the various explanations and mechanisms of heterosis in rice, including evidence fitting the established theories of heterosis and the use of modern omics approaches to characterizing heterosis and heterosis-related traits. Overdominance was the most frequently cited mechanism behind yield-related traits and various molecular and physiological markers associated with heterosis were identified.

Wheat (Triticum aestivum) is one of the most important cereal crops, providing essential food and nutrition for humans. Wheat powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici (Bgt), seriously threatens wheat production by reducing yield and quality. Utilizing effective powdery mildew resistance (Pm) genes to develop resistant cultivars is a powerful means for controlling this disease. In this study, we identified a new resistance gene, PmL270, from the wheat line L270. By means of bulked segregant RNA‑Seq (BSR‑Seq) and molecular marker analysis, we fine-mapped PmL270 to a 0.1-cM interval on chromosome 7AL, flanked by the markers X7AL07 and X7AL09. This interval corresponds to a 630-kb region in the reference genome of Chinese Spring. Comparative analysis showed that PmL270 is distinct from other Pm genes previously reported on the same chromosome arm. A co-dominant marker, X7AL08, developed from a candidate NLR gene, co-segregated with PmL270 in the mapping population and showed high specificity for this gene. The mapping and development of co-segregation marker will facilitate the cloning of PmL270 and contribute to its rapid utilization in wheat resistance breeding.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01574-0.

Tiller number is a key determinant of the number of spikes per plant, significantly influencing yield. Here, we identify and characterize a novel tiller inhibition line, N2496. Using an F₂ segregating population derived from crossing N2496 and CN16, we mapped this locus. The F₁ line demonstrated a high number of tillers, while the F₂ population exhibited segregated ratios of 3:1 in tiller number. BSR-Seq analysis indicated that only one locus controls tiller number, located on chromosome 2B (Chr. 2B). This genetic analysis confirmed the presence of a single recessive locus controlling the tiller inhibition trait within this population. Subsequently, we constructed a genetic map on Chr. 2B using a wheat 55 K single nucleotide polymorphism array. By combining recombinant analysis with the genotype and phenotype of the F_2-3 family, we identified and named a major and novel locus, tiller inhibition gene (tin7), mapped within a 2.43 cM interval. The influence of tin7 was verified across six different background populations all sharing N2496 as a common parent. Using new recombinant lines from these six populations, we further narrowed down the interval of tin7 to a genetic interval of 2.08 cM. Analysis of thousand grain weight and grain-related traits suggests that by regulating tiller number, tin7 holds the potential to increase yield in wheat. Our research provides access to a novel tiller number locus and available markers for regulating tiller number, which could be used in developing new cultivars with an optimal number of tillers.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01567-z.

Wheat serves as the primary source of staple food for the global human population, thus also making it a significant portion of the calorie intake in our daily vegetarian diets. However, in most of the improved wheat cultivars used for food, the grain is deficient in iron (Fe) and zinc (Zn). Therefore, biofortification involving improvement of grain Fe and Zn has become an important area in the current wheat breeding programmes. For this purpose, efforts have been made to develop alien substitution lines and utilize them for transfer of desirable alien genes to improved wheat cultivars. In the present study, two such genotypes in the background of improved cultivar PBW343LrYr were utilized for pyramiding of the following six desirable genes for enrichment of grain Fe and Zn: IRT2, MTP3, IREG, FRO7, YSL15 and NAS2. A forward breeding strategy, involving crossing of the two genotypes followed by inbreeding was used. Marker-assisted selection (MAS) of the genes of interest associated with grain Fe/Zn and plant type was used following selfing of F₁ hybrids. The grains of F₆ lines that were derived in this programmes were rich in both Fe and Zn contents in the grain. Among the six best derived lines, the values of improved contents of grain Fe ranged from 47.3 to 60.4 ppm and that of Zn ranged from 39.35 to 47.85 ppm. There was no yield penalty in these improved lines, such that the yield was either equal or better than the checks used in field trials.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01566-0.

Exploring the molecular mechanism underlying plant architecture and breeding new varieties suitable for mechanized harvesting are primary objectives for rapeseed breeders in China. However, few genes controlling plant architecture have been cloned in Brassica napus. In this study, SX3, a scattered-bud B. napus line with a dwarf and compact plant architecture, was characterized. To identify the genes underlying bud arrangement, plant height and branch angle, segregating populations were constructed by crossing SX3 with two clustered-bud lines with a tall and loose plant architecture. Genetic analysis revealed that the scattered-bud trait (SBT) was controlled by a single dominant gene, BnaSBT. BnaSBT is likely a pleiotropic gene that simultaneously controls plant height and branch angle. Using BSA-seq analysis, BnaSBT was mapped to a 4.15 Mb region on ChrA10. Owing to the lack of recombinants within this region, it was infeasible to finely map BnaSBT. RNA-seq analysis of BC₂ plants with contrasting inflorescence and plant architectures revealed that the upregulation of genes involved in amino acid and lipid metabolism and genes encoding MADS-box transcription factors is related to the the phenotype of SX3. These findings together with comparative sequencing indicated that BnaA10.SEP1, BnaA10.AGL15, BnaA10.GLN1-4 and BnaA10.AGP15 are candidate genes for BnaSBT. Markers closely linked to the scattered-bud trait were developed for selecting dwarf and compact plants. These findings provide molecular markers and germplasms for breeding new varieties with ideal plant types and lay a theoretical foundation for cloning key genes and elucidating the genetic basis of inflorescence and plant architectures in B. napus.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01556-2.

Winter wheat must undergo vernalization to flower, while spring wheat does not require vernalization. The requirement for vernalization in wheat is primarily controlled by vernalization genes. VRN-1 are the most important vernalization genes. The recessive vrn-1 alleles have a strict vernalization requirement, while dominant mutations in Vrn-1 eliminate or reduce this requirement. In this study, the near-isogenic lines for several VRN-B1 allelic variants (Vrn-B1a, Vrn-B1b, Vrn-B1c, Vrn-B1 d and vrn-B1) were generated in two winter wheat backgrounds. Under field conditions, the four dominant Vrn-B1 allelic variants (Vrn-B1a, Vrn-B1b, Vrn-B1c, and Vrn-B1 d) resulted in an advancement in the heading date by 3-5 days. Using an artificially controlled gradient vernalization treatment (4-5 ℃, ranging from 0 to 45 days with 5-day intervals), the vernalization requirements of VRN-B1 allelic variants were analyzed. The relative effects on vernalization requirements were found to be vrn-B1 > Vrn-B1a = Vrn-B1 d > Vrn-B1b = Vrn-B1c (opposite to the heading date). Gene expression analysis indicates that the earlier heading associated with the dominant Vrn-B1 allelic variants is linked to their open expression under non-vernalization conditions. There may be an expression threshold at the VRN-B1 locus that eliminates the vernalization requirement, and this threshold should be lower than the vrn-B1 levels observed under saturated vernalization conditions. Furthermore, once this hypothesized threshold is reached, there appears to be no dosage effect on VRN-B1 expression. These results deepen our understanding of wheat vernalization genes and provide a theoretical basis for utilizing these genes in breeding programs aimed at improving wheat adaptability.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01565-1.

Late blight (LB), caused by Phytophthora infestans, is a destructive disease of the cultivated tomato, Solanum lycopersicum. Environmental concerns and pathogen resistance have propelled research towards developing host resistance. The current LB-resistant cultivars of tomato exhibit susceptibility under severe disease pressure, necessitating the identification, characterization, and incorporation of additional resistance genes into new tomato cultivars. Recently, we identified Solanum pimpinellifolium accession PI 270443 with strong resistance to LB and developed a RIL population from its cross with an LB-susceptible tomato breeding line. In the present study, we constructed a high-density genetic map of the RIL population, using 8,470 SNP markers set into 1,195 genomic bins, with a total genetic distance of 1232 cM and an average bin size of 1 cM. We identified 2 major adjoining LB-resistance QTLs on chromosome 10 and a few minor QTLs on chromosomes 1 and 12 of PI 270443. While one of the QTLs on chromosome 10 colocalized with the known LB-resistance gene Ph- 2 and a LB-resistance QTL previously identified in an F₂ population of the same cross, the present study allowed marker saturation of the region, fine mapping of the QTL, and identification of candidate resistance genes in the region. One of the 2 major QTLs on chromosome 10 and the 3 QTLs on chromosomes 1 and 12 were not previously reported in S. pimpinellifolium for LB resistance. These results will expedite transferring of LB resistance from PI 270443 into the tomato cultigen via MAS and discovering the underpinning LB-resistance genes in PI 270443.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01560-6.

Enhancing wheat yield and stress tolerance is a critical long-term objective for global food security. Historically, breeders selected genetic traits from wild wheat relatives for domesticated targets, such as non-shattering and free threshing characteristics, and developed the cultivated wheat. However, the genetic diversity of the cultivated wheat has become narrow after long-term domestication and conscious selection, which seriously limited the yield potential and stress tolerance. Therefore, using wild Triticeae species to broaden the gene pool is an ongoing task for wheat improvement. Psathyrostachy huashanica Keng ex P. C. Kuo (2n = 2x = 14, NsNs), a perennial species of the genus Psathyrostachys Nevski, is restrictively distributed in the Huashan Mountain region of Shaanxi province, China. P. huashanica exhibits considerable potential for wheat breeding due to its valuable agronomic traits such as early maturation, more tillers, abiotic tolerance, and biotic resistance. Over the past four decades, researchers have successfully crossed P. huashanica with common wheat and developed derivative lines with improved agronomic traits. Here, we summarized the morphology, genomic evolution, and derived wheat breeding lines with advanced agronomic characteristics inherited from P. huashanica. This review provides a useful guideline for future research on P. huashanica, and highlights its importance in wheat breeding.

Olive fruit weight is a crucial trait to consider in olive breeding programs due to its impact on final yield and its relevance for mechanical harvesting and fruit processing. Although environmental conditions influence this trait, fruit weight is primarily determined by genetic factors and exhibits a high degree of heritability in breeding progenies. Despite several studies identifying potential markers associated with fruit weight, these markers have not been validated. In this study, we analyzed 40 genetic markers linked to fruit weight using a dataset comprising 73 cultivars (including 33 newly sequenced varieties) and 10 wild olives with a wide range of phenotypic characteristics, spanning from very light (0.41 g) to very heavy fruits (8.57 g). By examining the phenotype distribution for each genotype of the newly sequenced varieties, we successfully validated 16 genetic markers. Additionally, machine learning tools demonstrated that 9 out of the 16 validated markers have a high predictive ability for fruit weight. As a result, our work provides, for the first time, a set of 9 well-validated genetic markers suitable for use in marker-assisted selection during the early stages of olive breeding programs.

Root is an important tissue to absorb water and nutrients from soil in plant and root architecture is one of critical traits influencing grain yield in crop. However, the genetic basis of root architecture remains unclear. In the present study, we identified a wild rice (Oryza nivara) introgression line Ra33 with longer seedling root length compared with the recipient parent 9311, an indica variety. Observation of longitudinal sections of root showed that the meristem length of Ra33 was significantly longer than that of 9311. Using an F₂ secondary segregating population derived from a cross between introgression line Ra33 and the recipient parent 9311, we detected a major QTL for root length at early seedling stage, qROL1, between the molecular markers M3 and M5 on chromosome 1, and the O. nivara-derived allele at qROL1 increased root length under the background of 9311. In addition, the near-isogenic line NIL-ROL1 showed a significant increase in root length compared with the recipient parent 9311, further demonstrating the genetic effect of qROL1. And then, a total of 159 recombinant individuals were screened from 3355 F₂ individuals and the QTL qROL1 was narrowed down to an approximate 78 kb interval between markers M4 and RM3, including 12 predicted genes. Further sequence comparison and expression analysis of the predicted genes in the fine-mapping region indicated that eight genes might be the interesting candidates of qROL1. The findings will provide new clues to reveal the genetic basis of root length and genetic resources for root architecture improvement in rice.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01564-2.