Molecular Breeding最新文献

Heterosis has been widely applied in crops production. Nonetheless, how to determine the favorable recombination of non-alleles remains elusive. Due to the uncertainty of genetic recombination, hybrids with strong heterosis tend to be selected empirically, by developing and testing a tremendous number of combinations. Here, we found some individuals in recombinant inbred lines (RILs, F₉) that were generated from hybrid F₁ (HRF₁) with heterosis performed transgressive segregation for yield in multiple environments. The result suggested that the formation of yield heterosis in hybrid was caused by the effective recombination of genes or QTLs. We performed multiple regression analysis (MRA) and redundancy analysis (RDA) using 11 traits measured in four environments. Of these traits, percentage of female flowers (PFF), fruit length (FL), fruit neck length (FNL), vine length (VL) and vine diameter (VD) contributed to increase yield. Moreover, the genes or QTL of yield contributor traits were identified by the molecular mapping strategy. We predicted a fl7.1 candidate gene that encoding a KIP1-like protein through correlation analysis between haplotype and fruit length phenotype. Based on the phenomenon some RILs individuals performed transgressive segregation and genetic theory, we proposed the model that the genetic sources of heterosis are contributed by combination of heterozygotic advantages and genetic recombination effects. Our work provides the theoretical basis for the pyramid of contributor genes or QTL for yield heterosis. This work also may facilitate Marker-assisted Selection for promote hybrid pyramid breeding and makes yield increasing more predictable in cucumber.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01551-7.

In peach, a long peduncle can help minimize mechanical damages/physical injuries in the fruit at harvest and can also be useful in postharvest handling and transportation. In view of genetically dissecting the peduncle length (PL) in peach, we have performed a Quantitative Trait Locus (QTL) mapping study for PL using a F₂ progeny of 117 individuals from the cross 'PI 91459 [NJ Weeping]' x 'Bounty' (WxBy). The progeny was phenotyped for three years (2011, 2012 and 2014) and the QTL mapping analysis was performed using four methods: Kruskall-Wallis, Interval Mapping, Multiple QTL Mapping and Genome-Wide Composite Interval Mapping. QTL analysis led to the identification of 9 QTLs distributed on linkage groups (LG) 1, 2, 4, 5, 6 and 7. A stable QTL was identified on LG6 (22,978,897 to 24,666,094 bp) and explained up to 63% of the phenotypic variance. Within the genetic interval of the stable QTL on LG6 potential candidate genes with functional annotation encompassing cellular expansion, hormone regulation, transcriptional regulation, developmental processes such as meristem development, and responses to environmental cues were found. The results reported in this study represent the first insight into the genetic basis of PL and a step forward towards the introduction of novel traits in peach commercial breeding in order to minimize the problems related to mechanical damage/injuries to peach fruits that commonly might occur during at harvest and post-harvest processes.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01547-3.

Gray leaf spot (GLS) is one of the most damaging foliar diseases in maize. In previous research, we identified the ZmCPK39 gene, which confers resistance to GLS. This study demonstrates the utility of ZmCPK39 in breeding resistant maize varieties. Two parental lines of Zhengdan958 (the most widely cultivated hybrid in China), Chang7-2 and Zheng58, were selected for resistance improvement. These lines were crossed with Y32, a donor line high resistance to GLS, followed by six rounds of backcrossing to their respective recurrent parents. Foreground selection was performed in each generation to detect ZmCPK39, while background selection was conducted in the BC₆F₁ generations using a Maize 6 K DNA chip. The converted lines, Chang7-2 ^ZmCPK39 and Zheng58 ^ZmCPK39 , with a recovery rate of 94.67-96.48%, were crossed to produce the improved hybrid Zhengdan958 ^ZmCPK39 . This hybrid exhibited enhanced GLS resistance and an 11.95% higher yield under severe disease stress, while maintaining comparable yield performance under normal growth conditions relative to the original Zhengdan958. This study highlights the breeding potential of ZmCPK39 for improving GLS resistance in maize.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01549-1.

Maize, a primary global food crop, is crucial for food security. In recent years, climatic and other abiotic stresses have led to frequent global droughts. Ascorbate peroxidase (APX) plays a vital role in the ascorbate-glutathione cycle. Under drought stress, APX effectively scavenges reactive oxygen species (ROS) produced by plants and maintains the normal growth and development of organisms. This study successfully amplified APX-related genes, and the ZmAPX2 gene was screened using expression analysis. pCAMBIA3301-ZmAPX2-Bar and pCXB053-ZmAPX2-Bar plant expression vectors were constructed and transformed into the maize inbred line H120. Drought tolerance of plants was analyzed by phenotypic characteristics, physiological and biochemical indices in T₂ generation positive maize seedlings as well as agronomic traits at maturity. Results indicate that boosting APX2 gene expression enhances maize drought resistance by reducing ROS content. This research underpins the exploration of new drought-tolerant maize germplasm and resistance mechanisms.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01548-2.

Heterosis, a key technology in modern commercial maize breeding, is limited by the narrow genetic base which hinders breeders from developing superior hybrid varieties. By integrating big data and functional genomics technologies, it becomes possible to create new super maize inbred lines that resemble hybrid varieties through the aggregation of multiple QTL parental advantage loci. In this study, we utilized a combination of resequencing and field selfing selection methods to develop three pyramiding QTL lines (PQLs) (PQL4, 6, and 7), each containing 15, 12, and 12 QTL loci respectively. Among the three PQLs, PQL6 (266.78 cm/119.39 cm) demonstrated hybrid-like performance comparable to the hybrid (276.96 cm/127.02 cm) (P < 0.05). Testcross between PQL6 and the parental lines revealed that PQL6 had accumulated and fixed advanced parent alleles for superior traits in plant and ear height. The significant increase in PQL6 plant height primarily resulted from the aggregation of two major effective QTL (qEH2-1 and qEH8-1 on chromosomes 2 and 8), indicating that the aggregation of major effective QTL is a key selection indicator. Furthermore, PQL6 exhibited slow vegetative growth but experienced a rapid height increase during the reproductive stage, particularly in the 1-2 weeks before flowering, when its growth rate accelerated and surpassed that of the hybrid varieties. Our study explored the time period and key parameter indicators for molecular breeding of maize, providing a theoretical concept and practices for further complex multi-trait design and aggregation.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01546-4.

[This corrects the article DOI: 10.1007/s11032-024-01522-4.].

The stigma exsertion rate (SER) is a key factor in improving the outcrossing ability of cytoplasmic male sterility (CMS) lines in rice. In previous studies, we identified 18 SER-QTLs and developed some SER-QTL pyramiding lines (PLs). In this study, 4QL-1 and 4QL-2 were selected from these PLs and crossed with CMS maintainer lines H211B and H212B, respectively, to develop two new CMS maintainer lines, H221B and H222B, and their CMS lines H221A and H222A. The SER of H221B and H222B were 74.7% and 73.1%, respectively, reaching a high SER level. Compared with CMS maintainer lines, the CMS lines consistently exhibited higher SER, which may be related to the delayed flowering time of the CMS lines. Filed experiments showed that outcrossing seed-setting rates of H221A and H222A were significantly higher than those of the original CMS lines, which meets the requirements for hybrid rice seed production. These results confirm that SER is a key factor in enhancing rice outcrossing ability. Our findings demonstrate that pyramiding SER-QTLs is an effective strategy for improving rice SER and increasing outcrossing seed-setting rate.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01545-5.

Rice (Oryza sativa L.) is a crucial staple food for most of the world's population. However, it is highly vulnerable to low temperatures, which can induce growth retardation and yield loss. In this study, we aimed to develop SNP- and Indel-based molecular markers for the key cold tolerance-related genes HAN1, COLD11, and COLD1. The HAN1 marker was designed using a KASP assay, which was effective for fluorescence-based detection, whereas COLD11 and COLD1 markers were gel electrophoresis-compatible, enabling easy application without complex equipment. Considering the polygenic nature of cold tolerance, we analyzed combined markers, which exhibited enhanced prediction accuracy compared to single-marker analysis. Based on these markers, we categorized 372 rice cultivars into seven genotypic groups and assessed their genotypic and phenotypic data. The cold-tolerant HAN1 genotype was absent in the Tongil and indica cultivars but conferred the highest cold tolerance to japonica cultivars, highlighting the crucial role of HAN1 in the cold stress response. The COLD1 genotype and GCG repeat number of COLD11 are crucial for cold tolerance. Analysis of a doubled haploid population derived from a cross between the '93-11' and 'Milyang352' confirmed that the number of COLD11's GCG repeats significantly influence cold tolerance, followed by COLD1. Combining multiple cold-resistant alleles improved overall tolerance and post-stress recovery. Identifying additional alleles associated with cold stress resistance could aid in the selection of Tongil cultivars with enhanced cold tolerance. These markers could potentially contribute to breeding programs for the identification and selection of cold-tolerant rice varieties.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01543-7.

Factors that restrict the development of genetic transformation include the long cycle, extensive requirements for experimental conditions, and low survival and transformation rates. Especially for plants that obtain offspring through sexual reproduction. This study established the genetic transformation methods that are particularly suitable for it. First, a rapid in vivo transformation system of adventitious roots was developed using A. rhizogenes to infect normally growing watermelon stem nodes without requiring plant treatment, enabling the stable genetic transformation of adventitious roots. And the genetic transformation efficiency of adventitious roots reaches 100%. Second, the traditional genetic transformation system was improved using A. rhizogenes which induces rooting of explants and promotes the regeneration of adventitious buds. The genetic transformation efficiency of adventitious roots reaches 100% and adventitious buds reaches 40%, which is much higher than using A. tumefaciens. Third, in order to achieve shorten the regeneration cycle and high transformation efficiency, the genetic transformation method without tissue culture was established using A. rhizogenes to infect the seed. This genetic transformation efficiency of transgenic plants reaches 80%, and it is not limited by genotype. This study significantly improves the plant regeneration and low genetic transformation efficiency while promoting the rapid development of watermelon molecular breeding.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01544-6.

This study is the first to develop a method for cadmium enrichment and identification in sterile rice lines. The important low-cadmium rice resources Luohong 3A and Luohong 4A were discovered. A precise breeding system for low cadmium enrichment in rice was established, leading to the cultivation of Xizi 3, the first low-cadmium rice variety approved by the State. This achievement is significant for solving the problem of excessive cadmium in rice in southern China. In 2024, Xizi 3 was selected as a major agricultural technology by the Ministry of Agriculture and Rural Affairs and a key scientific and technological achievement in China's agricultural and rural areas.