Hybrid breeding enhances forest genetic improvement by conferring offspring stronger vitality through gene recombination. This study used Catalpa bungei(Q), Catalpa fargesii f. duclouxi(D), and Catalpa fargesii(H) for artificial hybridization, with a natural C. fargesii f. duclouxi hybrid population as control. Mating types were DZ (D × D), HD (H × D), HQ (H × Q), QD (Q × D), and QQ (Q × Q). Annual growth and wood properties were analyzed to evaluate suitability for central China's low mountain hills and elucidate growth advantages. Results indicate: (1) Survival rates ranked QQ > QD > HQ > DZ > HD. Except 2012 height, mating types showed highly significant (p < 0.01) differences in H and DBH across years, and significant differences (p < 0.05) in Pilodyn and modulus of elasticity (MOE). Mating type × block interaction was significant only for 2020 MOE. (2) H and DBH growth trends were similar; QQ and DZ had significantly larger increments. QQ showed the smallest Pilodyn (24.5 mm, highest density) and largest MOE (6.5 GPa). (3) Height and DBH (2012, 2016, 2020) showed significant (p < 0.05) or highly significant (p < 0.01) correlations, strongest between 2016–2020. DBH correlated negatively with Pilodyn and positively with MOE. 4)​​ Comprehensive Qi values ranked QQ (1.97) > QD (1.95) > DZ (1.85) > HD (1.80) > HQ (1.64), with QQ highest. Findings confirm QQ (C. bungei × C. bungei) is optimally suited for central China low mountain hills, providing support for Catalpa genetic improvement and economic utilization.

Primula beesiana is a perennial herbaceous plant predominantly distributed in the alpine wetland regions of Yunnan Province, China. This species faces dual threats from habitat fragmentation and climate change, but research into its genetic background is severely lacking. Consequently, systematic analysis of the genetic diversity and population structure of Primula beesiana is crucial in formulating scientific conservation strategies. In this study, 86 individuals from six natural populations in Lijiang City, Yunnan Province, were collected and genotyped using double-digest restriction site-associated DNA sequencing (ddRAD-seq). A total of 1537 high-quality SNP loci were identified and used for genetic diversity, principal component (PCA), population structure (STRUCTURE), and gene flow analyses. Analysis of base substitutions revealed twelve mutation types, with transversions accounting for 67.9% and a transition/transversion ratio (Ti/Tv) of 0.47, potentially indicating strong environmental selection pressure. Although high overall genetic diversity was observed, significant genetic differentiation may exist among populations (Fst = 0.0056-0.0407), with heterozygote deficiency detected across all populations. Genetic structure analyses consistently grouped the six populations into four distinct clusters. Populations MDJ, WH, and HS each formed independent clusters, exhibiting clear genetic isolation, whereas XHC2, XHC1, and NX clustered together, showing high genetic similarity and frequent gene flow. Mantel tests demonstrated a significant positive correlation between genetic and geographical distances (r = 0.854, p < 0.01), supporting an isolation-by-distance model. Gene flow estimates varied considerably among populations (5.90-44.69) and decreased with increasing geographical distance. This study provides the first genomic-level evidence of significant genetic differentiation and isolation based on distance in Primula beesiana populations, offering crucial scientific support in identifying evolutionarily significant units and developing zoned conservation management strategies for this species.

Toona sinensis is prized for its superior wood quality, ranking among the most important timber species. However, its growth and development has been severely constrained by persistent drought stress, which has become more frequent due to global climate change. Therefore, elucidating its drought response mechanisms and breeding high-yield, drought-resistant varieties are crucial for mitigating plantation productivity losses caused by global climate change. This study analyzed the effects of genotypic (G), environmental (E), and genotype-byenvironment (G & times;E) interactions on the growth, leaf morphology, anatomy, and S13C of T. sinensis clones in three test sites. We evaluated the key traits associated with drought response, and investigated the relationship between growth and drought resistance. The results revealed significant genotypic and G & times;E effects on volume. Leaf phenotypic variation was primarily determined by G & times;E effects, though leaf thickness and S13C exhibited significant genotypic effects. In severely water-deficient regions, clone volume significantly decreased, leaf area reduced, leaf thickness increased, and S13C markedly rose. Among leaf-related traits, S13C was identified as a key indicator of drought response, with its increase mainly attributed to enhanced leaf thickness due to palisade tissue thickening. Regression analysis showed no significant correlation between the comprehensive drought resistance index (based on leaf phenotypes) and volume. Thus, clones were evaluated separately across three test sites. On the basis of high volume, potentially drought-resistant clones were further screened (XC10-4 and XC15-3 for XT; XC6-17 and XC30-2 for HZ; XC15-3 and XC6-13 for LA), all achieving genetic gains in volume exceeding 20 %. These findings provide practical insights for the sustainable development of future T. sinensis plantations.

Toona sinensis is a high-value cultivated timber tree for which efficient clonal screening across heterogeneous environments is important. We evaluated whether two nitrogen-normalized phenotypic indices provide useful information beyond their component traits: a structural index (S-NNI = LMA/LN) and a height index (H-NNI = H/(LN+RN)). Eighteen clones were tested at three field sites in China (Lu’an, Heze, and Xingtai). Validation combined algebraic-coupling diagnosis, allometric tests, agreement with non-ratio residuals, external criterion validity, grouped leave-one-clone-out cross-validation, and within-site rank changes. S-NNI agreed strongly with the non-ratio LMA residual (ρ = 0.734, 95% CI = 0.559–0.830) and was positively associated with site-adjusted palisade tissue thickness (ρ = 0.313, 95% CI = 0.031–0.581). For leaf thickness and palisade tissue thickness, the S-NNI model produced the highest leave-one-clone-out R² values among six candidate models (0.176 and 0.163, respectively), although its RMSE advantage over the site-only and quadratic models was uncertain. H-NNI showed moderate agreement with the non-ratio height residual (ρ = 0.478) and site-adjusted DBH (ρ = 0.576), increasing DBH prediction R² from 0.865 in the site-only model to 0.913. However, additive and interaction models retaining H, LN, and RN performed better, and H-NNI provided no independent information after adjustment for its components. Within-site rankings changed most for S-NNI in Xingtai and H-NNI in Heze. S-NNI may therefore serve as a parsimonious preliminary descriptor of leaf structural phenotype, whereas H-NNI should be restricted to exploratory detection of ranking discordance. Neither index represents nitrogen-use efficiency or replaces production traits, direct component analysis, or multi-environment stability assessment.

Neocinnamomum plants are considered a promising feedstock for biodiesel in China, due to the richness in long-chain fatty acids (LCFAs) found in their seeds. However, the mitochondrial genome (mitogenome) of this genus has not yet been systematically described, and the exploration of species relationships within this genus using mitogenome sequences is also an uncharted territory. This has hindered our understanding of mitogenome diversity and the evolutionary relationships within Neocinnamomum. In this study, a total of 24 individuals representing seven distinct taxa from the genus Neocinnamomum were subjected to Illumina sequencing, and the species N. delavayi was sequenced using Oxford Nanopore sequencing technology. We successfully assembled the mitogenome of N. delavayi, which is 778,066 bp in size and exhibits a single circular structure. The analysis identified 659 dispersed repeats, 211 simple sequence repeats (SSRs), and 30 tandem repeats within the mitogenome. Additionally, 37 homologous fragments, totaling 9929 bp, were found between the mitogenome and the plastid genome (plastome). The codons of 41 protein-coding genes (PCGs) had a preference for ending in A/T, and the codon usage bias of the majority of these genes was influenced by natural selection pressures. Comparative genomic analysis revealed low collinearity and significant gene rearrangements between species. Phylogenetic analysis resulted in the classification of Neocinnamomum into six distinct clades, contradicting previous findings which based on complete plastomes and nuclear ribosomal cistron (nrDNA). In the PCGs of 24 individuals, 86 mutation events were identified, which included three indels and 83 SNPs. Notably, the ccmC gene underwent positive selection in pairwise comparisons of three species pairs. Furthermore, 748 RNA editing sites were predicted within the PCGs of the N. delavayi mitogenome. This study enriches our knowledge of the mitogenomes in the family Lauraceae, and provides valuable data and a foundation for genomic evolution research, genetic resource conservation, and molecular breeding in Neocinnamomum.

The tropial genus Beilschmiedia, comprising over 250 species worldwide, includes approximately 40 species distributed in the northern tropical forests of Asia. However, the phylogenetic relationships among these Asiatic Beilschmiedia species remain incompletely understood. In this study, we sequenced and assembled complete chloroplast genomes from six Asiatic Beilschmiedia species, including five from China and one from Indonesia. The genomes range in size from 158,275 to 158,620 bp and exhibit a typical quadripartite structure, similar to other basal Lauraceae species. We identified 116 to 122 simple sequence repeats (SSRs) and 19 to 28 dispersed repeats within the genomes. The relative synonymous codon usage (RSCU) of 79 protein-coding genes exhibited minimal variation. Notably, the boundary genes rpl23 and ycf1 displayed varying degrees of expansion and contraction, along with incomplete replication phenomena. Using a sliding window approach, we constructed a coalescent tree with ASTRAL software to analyze the phylogenetic relationships. The resulting main topology was highly consistent with the Maximum Likelihood (ML) and Bayesian inference (BI) analyses, clearly dividing the Asiatic core Beilschmiedia into two distinct groups: Group A and Group B. Group A showed an extremely low nucleotide diversity (π) value of 0.00063, while Group B exhibited 2.79-fold higher diversity. The highly variable regions trnS-trnG and rpl32-trnL are proposed as molecular markers for distinguishing between Groups A and B. Furthermore, we identified seven additional highly variable regions: ndhF, ndhF-rpl32, rpl2, rpl2-trnH, rpl32, rps15-ycf1, and ycf1. These regions may serve as potential molecular markers for the Asiatic Beilschmiedia species. These findings provide new insights into the phylogenetic relationships among Asiatic Beilschmiedia species, highlighting the potential of specific molecular markers in future research.

Camphora Fabr. is a genus in the family Lauraceae, comprising over 20 tropical and subtropical tree species. Since the genera Camphora and Cinnamomum Schaeff. were described, there has been a long-lasting controversy regarding the phylogenetic relationships among taxa in both genera. In particular, phylogenetic inferences derived from plastid data remain debated, with varying hypotheses proposed and occasional disputes concerning the monophyly of Camphora taxa. To further investigate the relationships, We analyzed plastomes and nuclear ribosomal cistron sequences (nrDNA) of 22 Camphora taxa, 15 Cinnamomum taxa, and 13 representative taxa of related genera. The Camphora plastomes range from 152,745 to 154,190 bp, with a GC content of 39.1% to 39.2%. A total of 128 genes were identified in the Camphora plastomes, including 84 protein-coding genes, 8 rRNA genes, and 36 tRNA genes. A total of 1130 SSR loci were detected from plastomes of Camphora, and A/T base repeats looked like the most common. Comparative analyses revealed that the plastomes of Camphora exhibit high similarity in overall structure. The loci ycf1, ycf2, trnK (UUU), psbJ-psbL, and ccsA-ndhD were identified as candidate DNA barcodes for these taxa. Plastome phylogenetic analysis revealed that Camphora is not monophyletic, whereas the nrDNA dataset supported the monophyly of Camphora. We propose that intergeneric hybridization may underlie the observed discordance between plastid and nuclear data in Camphora, and we recommend enhanced taxonomic sampling and precise species identification to improve phylogenetic resolution and accuracy.

The taxonomy of Eriobotrya and Rhaphiolepis has long been contentious due to unclear interspecific relationships, morphological ambiguities, low barcode resolution, and lack of molecular phylogenetic support. Using shallow genome sequencing, this study analyzed 29 newly assembled chloroplast genomes (159,101-159,718 bp; GC 36.6%-36.7%) comprising 113 unique genes (78 protein-coding, 31 tRNA, and 4 rRNA). Structural variation was observed in the rpl2-trnH spacer along with six small inversions. Comparative analyses revealed 13 highly variable regions in Eriobotrya, 2 in Rhaphiolepis, and 12 shared regions. Phylogenomic analysis of 42 plastomes resolved five well-supported clades, confirming the monophyly of each genus. Nuclear-plastid conflict in species such as Eriobotrya japonica suggests ancient hybridization and chloroplast capture, likely linked to overlapping flowering times and distributions. These findings clarify phylogenetic relationships and provide theoretical and practical support for taxonomy, germplasm utilization, and genetic research of Eriobotrya and Rhaphiolepis.

Bract coloration is one of the key ornamental traits in Bougainvillea, yet research has predominantly focused on phenotypic color traits and pigment composition, with limited understanding of the molecular mechanisms underlying color formation. This gap hinders the improvement and innovation in bract coloration. To elucidate the regulatory mechanisms of bract coloration in Bougainvillea and to enhance the utilization of its germplasm resources, this study employed the Illumina Novaseq 6000 sequencing platform to conduct transcriptomic sequencing on 21 samples of bracts exhibiting seven distinct phenotypes. Comparative analysis against Nr, Pfam, EggNOG, GO, and KEGG databases annotated 90,279 unigenes. The highest annotation rates were achieved with the Nr (40.13%), GO (30.44%), and EggNOG (25.64%) databases. Among the species annotated, Beta vulgaris (20.08%) and Chenopodium quinoa (14.58%) shared the highest homology with Bougainvillea bract transcriptomes. WGCNA analysis identified 12 positively correlated tissue-specific modules, of which 2 are related to bract color formation. By comparing transcriptome data and genes within these specific modules against the KEGG database, a total of 321 unigenes associated with bract color formation in Bougainvillea were discovered. Among these, 220 unigenes are involved in anthocyanin synthesis, 43 unigenes are involved in betalain synthesis, 23 unigenes are annotated as Chlorophyll a-b binding protein genes, and 35 unigenes participate in carotenoid synthesis. Quantitative real-time PCR (qRT-PCR) validation of 16 differentially expressed genes (DEGs) including PAL2, CHS1, ANS, BZ1, 6GT, CDOPA5GT, ANR, CHS2, and DOPA, revealed significant expression differences among magenta, yellow, white, and cherry-colored bracts, suggesting their potential as candidate genes for bract color development. This study not only enriches the transcriptomic data of Bougainvillea but also identifies genes associated with bract coloration, providing a valuable theoretical basis for future gene cloning, genetic engineering, and breeding efforts in Bougainvillea.

Millions of years of isolation have given Madagascar a unique flora that still reflects some of its relationship with the continents of Africa and India. Here, the complete chloroplast sequence of Beilschmiedia moratii, a tropical tree in Madagascar, was determined. The plastome, with a length of 158,410 bp, was 143 bp and 187 bp smaller than those of two closely related species, B. pierreana and Potameia microphylla, in sub-Saharan Africa and Madagascar with published sequences, respectively. A total of 124 repeats and 114 simple sequence repeats (SSRs) were detected in the plastome of B. moratii. Six highly variable regions, including ndhF, ndhF-rpl32, trnC-petN, pebE-petL, rpl32-trnL, and ycf1, among the three African species were identified and 1151 mutation events, including 14 SVs, 351 indels, and 786 substitutions, were accurately located. There were 634 mutation events between B. moratii and P. microphylla with a mean nucleotide variability (π) value of 0.00279, while there were 827 mutation events between B. moratii and B. pierreana with a mean π value of 0.00385. The Ka/Ks ratios of 86 protein-coding genes in the three African species were less than 1, and the mean value between B. moratii and P. microphylla was 0.184, while the mean value between B. moratii and B. pierreana was 0.286. In this study, the plastid genomes of the three African Beilschmiediineae species were compared for the first time and revealed that B. moratii and P. microphylla from Madagascar were relatively conserved, with low mutation rates and slower evolutionary rates.

The genus Caryodaphnopsis, a member of the Lauraceae family, is characterized by seeds that are rich in oil, as well as highly exploitable fruits and wood. The Asian taxa within this genus exhibit complex morphological variations, posing challenges to their accurate classification and impeding their effective use and development as a resource. In this study, we sequenced the chloroplast genomes of 31 individuals representing nine Asian taxa within the Caryodaphnopsis genus. Our primary objectives were to reveal structural variations in these chloroplast genomes through comparative analyses and to infer the species' phylogenetic relationships. Our findings revealed that all chloroplast genomes had a tetrad structure, ranged in length from 148,828 to 154,946 bp, and harbored 128-131 genes. Notably, contraction of the IR region led to the absence of some genes in eight taxa. A comprehensive analysis identified 1267 long repetitive sequences and 2176 SSRs, 286 SNPs, and 135 indels across the 31 chloroplast genomes. The Ka/Ks ratio analysis indicated potential positive selection on the matK, rpl22, and rpoC2 genes. Furthermore, we identified six variable regions as promising barcode regions. Phylogenetic analysis grouped the nine Asian taxa into six branches, with C. henryi forming the basal group from which three distinct complexes emerged. This study contributes significantly to the current understanding of the evolutionary dynamics and phylogenetic relationships within the genus Caryodaphnopsis. Furthermore, the identified molecular markers hold potential for molecular barcoding applications in population genetics, providing valuable tools for future research and conservation efforts within this diverse genus.

本研究对锈毛莓(Rubus reflexus Ker.)叶绿体基因组进行测序及组装,获得了全长为 156 247 bp,GC总含量为 30.72%的核苷酸序列,注释出 129 个基因,其中 16 个基因有 2 个拷贝,9 个基因有内含子;密码子使用偏好结果显示,自然选择对锈毛莓密码子使用偏好影响最大,其次是突变压力;系统发育结果显示,锈毛莓(R.reflexus)与黄脉莓(R.xanthoneurus)和高粱泡(R.lambertianus)亲缘关系较近;叶绿体基因组全长比较分析结果显示,锈毛莓与近缘物种之间的变异主要存在于基因间隔区;通过核苷酸多态性分析筛选出 6 个高变区,即rps16-trnQ-UUG、petN-psbM、trnT-UGU-trnL-UAA、petA-psbJ、rpl32-trnL-UAG及ycf1.研究结果揭示了锈毛莓叶绿体基因组特征及系统发育关系,为锈毛莓及悬钩子属的比较基因组学研究、物种鉴定及遗传改良提供参考依据,同时也为解决悬钩子属部分物种分类混乱问题提供了新的解决方案.

Pinus yunnanensis)、思茅松(P.kesiya var.langbianensis)和卡西亚松(P.

本文从栽培技术、育种方法两方面总结了中国杜鹃花(Rhododendron)的保育研究进展,针对目前我国杜鹃花保育工作方法单一、野生资源保护和开发利用力度小、目标选育不够深入等不足,提出重点研究复合育种技术、加强野生杜鹃花保育研究,发挥资源优势,培育特色品种、有针对性地进行目标选育等建议,以期为今后我国杜鹃花的保育和应用发展提供参考.

PurposeTo excavate genes related to the number of cones in Pinus armandii. MethodsBased on the phenotypic data of cone number of P. armandii, the high and low cone number individual plants were screened. Combined with phenotypic data, single-nucleotide polymorphism (SNP) markers developed previously were used to genome-wide association study (GWAS), and the phylogenetic tree of P. armandii samples was constructed, the SNP markers and candidate genes related to cone number of P. armandii were excavated, and the tissue-specific expression of qPCR gene was further analyzed in six parts of P. armandii, such as needles, xylem, phloem, bark, young cones and roots. ResultsThe phylogenetic tree showed that the individual plants of the same provenance were basically in a similar position, while the individual plants from Weishan were widely distributed in each population, which was basically consistent with the results of principal component analysis. A total of 12 SNP loci significantly associated with cone number were detected by GWAS. It was found that the sequence of Marker193307 was highly similar to the cellulose synthesis related gene Korrigan (KOR1, encoding transmembrane endo-β-1,4-D glucanase) (74.74%). The tissue-specific expression of qPCR results showed that the expression level of the gene was the highest in the phloem of branches, followed by the young cones, and the least in the roots. It was preliminarily judged that the gene was related to the number of cones. ConclusionP. armandii provenance close to the individual basically in a similar position. The materials of Weishan provenance have more extensive genetic variation than other provenances. GWAS only retrieves one gene (KOR1) related to plant cellulose synthesis, which may be involved in the expression of cone number.

氨磺灵是一种三硝基苯胺类除草剂,在应用于植物多倍体的诱导中,取到了较好的诱导效果.本研究以氨磺灵为诱变剂,采用混培法对来自 3 个不同地点的滇杨材料进行多倍体诱导,探讨氨磺灵对滇杨的多倍化诱导效果,继而对诱导后的材料进行同质化处理,鉴定其倍性.结果显示:氨磺灵可诱导滇杨产生多倍体材料,变异率最高的处理组合为预培养 4 d后,在添加 50 mg/L氨磺灵的分化培养基(1/2 MS+TDZ 0.01mg/L+NAA 0.01mg/L)中培养 2 d,变异率可达 28.57%.多倍体植株与正常株形态差异明显,且染色体数目增加为 76 条,多倍体滇杨的荧光通道值约为二倍体滇杨的 2 倍,表明滇杨材料已加倍为四倍体.研究结果对滇杨乃至木本植物的多倍体育种具有重要的理论及实践意义.

为了研究不同浓度的银杏和鸡爪槭凋落物的浸提液对高羊茅种子萌发产生的影响,本文通过室内模拟试验,设置不同浓度的银杏和鸡爪槭叶片浸提液T1(10g·L-1)、T2(40g·L-1)、T3(80g·L-1)处理高羊茅种子.当浓度为80g·L-1时,银杏和鸡爪槭两者的叶片凋落物浸提液对高羊茅的种子萌发的抑制效果都最为明显,银杏和鸡爪槭的叶片凋落物浸提液的化感效应指数分别为-0.44与-0.21;当浓度为10g·L-1时,银杏叶片浸提液对高羊茅种子发芽既不促进也不抑制,其化感效应指数为0.00,而鸡爪槭叶片凋落物浸提液对高羊茅种子的萌发起到一定的促进效果,鸡爪槭的叶片凋落物浸提液的化感效应指数为0.03.结果表明,2种植物凋落物浸提液对高羊茅种子萌发表现为"低促高抑"效应,银杏凋落物浸提液的化感抑制作用强于鸡爪槭,化感效应指数(RI)表明银杏凋落物浸提液对高羊茅种子萌发的化感抑制作用更强.

Objective Means utilizing molecular markers to differentiate rapidly and accurately male and female Populus yunnanensis plants at young stages was investigated. Method Using simple sequence repeats (SSR), molecular markers were screened for those might associate with the sex of P. yunnanensis at seedling stages and before flowering. Result Fifteen pairs of SSR primers were selected from the reported literatures. One of them, coded BPCA90, showed clear bands and stable reaction in agarose gel detection. After rescreening the primer by polyacrylamide gel electrophoresis, a specific band of approximately 680 bp appeared in the PCR amplification of male P. yunnanensis. Subsequent testing on 30 plants using these SSR primers showed significantly more males than females in a ratio of 13 to 2. ConclusionShort of a visible morphological sign for the determination, the SSR primers screened by this study appeared to suffice the general purpose of differentiating the sex of P. yunnanensis at early growth stage.

Mangifera plants are tropical fruits that have high economic value and scientific utility. However, the chloroplast genome characteristics and phylogenetic relationships among Mangifera species remain unclear. In this work, we reconstructed maximum likelihood (ML) and Bayesian inference (BI) phylogenetic trees using 11 newly sequenced chloroplast genomes as well as six existing genomes obtained from the National Center for Biotechnology Information (NCBI) database. The chloroplast genomes all had a typical quadripartite structure, with lengths ranging from 157,368 to 158,942 bp. The GC-content in the genomes ranged from 37.8% to 37.9%. We found conserved boundaries comprised of two inverted repeats (IRs), large single-copy (LSC) regions, and small single-copy (SSC) regions. Nucleotide polymorphism analysis revealed three hypervariable regions (ycf4-cemA, rps18-rpl20, and rpl32-ndhF) in the LSC and SSC regions, which could potentially be used as DNA barcodes for Mangifera species. According to our phylogenetic analysis, Mangifera plants were clustered into three clades. Among them, all five samples of M. indica formed a monophyletic group in Clade Ⅰ. Clade Ⅱ included seven Mangifera species and could be further divided into five subclades with 100% branch support values. Clade Ⅲ included two M. persiciforma samples that formed a monophyletic group. Taken together, these results provide a theoretical basis for species determination, in addition to shedding light on the evolution of Mangifera.