Molecular Breeding最新文献

Taigu genic male-sterile wheat, containing the dominant gene male sterile (Ms) 2, shows completely male-sterility in different genetic background and under various environments. The development of Aibai wheat with tightly linked Ms2 and Reduced height (Rht)-D1c, offers possibility for identifying the male-sterile plants by investigation of reduced plant height. However, due to the extreme dwarfism of Aibai wheat caused by Rht-D1c, it inhabits a shadowed microenvironment caused by its fertile sibling plants. This results in delayed maturation of sterile plant progeny. In order to develop a novel germplasm with new visible marker for sorting male sterile plants conferred by Ms2, a binary vector containing Bar, Ms2, Rht-D1b, and DsRed driven by the aleurone-specific promoter Ltp2 was constructed and introduced into the wheat Fielder using Agrobacterium-mediated transformation in this study. After investigation of the fertility, plant height and seed fluorescence of positive transgenic wheat plants, a line exhibited semi-dwarf male sterility, which could be reliably identified by the aleurone-specifically expressed red fluorescence in seeds, serving as a genetically stable reporter. Therefore, this study provides a novel male-sterile wheat that offers a powerful tool for hybrid seed production and facilitates genetic improvement in wheat through recurrent selection.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01571-3.

Cowpea is an important grain legume crop and a source of vegetarian protein. C-152, a popular and widely adapted variety of cowpea, became susceptible to major cowpea diseases, viz., bacterial leaf blight (BLB) and cowpea mosaic virus (CpMV). Thus, in the current investigation, we have introgressed BLB and CpMV resistance from V-16 and V-57817, respectively, to the C-152 variety. A marker assisted simultaneous and stepwise backcross breeding scheme was used to recover an improved version of C-152 with resistance to BLB and CpMV diseases. Foreground (CISP markers VuMt401 and VuMt397 for BLB and SSR markers MA15 and MA80 for CpMV) and background selections were practiced using gene-specific and recurrent genome specific (72 markers) polymorphic markers. Two independent BC₂F₄ lines from each cross possessing blb-1 and cowpea mosaic resistance gene with maximum genome recovery of the C-152 were inter-crossed to derive an inter-cross (IC) F₄ population. Among the 10 promising ICF₄ progenies, the line MC 17-2 (KBC-12), showing high yielding with resistance to BLB and CpMV, was selected. The superiority of the cowpea line MC 17-2 was evident in terms of a yield advantage of 8.68 to 28.68%, 9.30-47.00%, 1.10-8.10% over different check varieties in the initial varietal trial, advanced varietal trial (AVT)-I, and AVT-II, respectively. Further, the multi-location evaluation of KBC-12 (MC 17-2) with the check KBC-9 covering zones 5 and 6 of Karnataka reconfirmed the high-yielding potential and stability of KBC-12 across tested environments, as evident from AMMI and GGE biplots. Thus, the promising cowpea line KBC-12 was released for commercial cultivation in zones 5 and 6 in southern India during 2024 and can also be used as a donor (IC652010) of BLB and CpMV resistance. Our current study is one such examples that revealed the power of marker-assisted selection to deliver improved cultivars from lab to farmers' field.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01570-4.

Walnut (Juglans regia L.), an important woody oil plant, is cultivated globally and has a prominent position in the world's major nuts. Heterozygosity enriches plant genetic diversity by providing a wider array of gene combinations, significantly enhancing their adaptability to the environment and consequently improving their survival ability. In this study, we found that the heterozygosity rate was significantly correlated with 21 traits. Heterogeneity rate showed the strongest positive correlation with yield and nutrition, while it showed the most significant negative correlation with tree height and precocity. Among these, 13 traits showed positive correlations, the remaining 8 traits exhibited negative correlations. We conducted an in-depth study on the characteristics of walnut whole-genome heterozygosity. By using the GWAS based on the heterozygosity rate, we successfully identified 11 significant loci and 4 candidate genes. In the analysis of local heterozygosity rate by GWAS, it was found that 63.8% exhibited trans-acting and 36.2% exhibited cis-acting. In addition, with the help of genomic residual heterozygotes, we enriched functional genes from 44 Pfam families related to growth regulation and development. Finally, it is worth mentioning that during the process of walnut improvement, we observed an increase in the heterozygosity rate of genes related to the flowering time. It is speculated that a higher level of whole-genome heterozygosity can enhance the environmental adaptability of plants and improve their growth performance. The results of this study may provide assistance for optimizing the breeding strategies of walnuts.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01572-2.

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.