Mango (Mangifera indica L.) has been widely cultivated as a culturally and economically significant fruit tree for roughly 4000 years. Despite its rich history, little is known about the crop's domestication, genomic variation, and the genetic loci underlying agronomic traits. This study employs the whole-genome re-sequencing of 224 mango accessions sourced from 22 countries, with an average sequencing depth of 16.37x, to explore their genomic variation and diversity. Through phylogenomic analysis, M. himalis J.Y. Liang, a species grown in China, was reclassified into the cultivated mango group known as M. indica. Moreover, our investigation of mango population structure and differentiation revealed that Chinese accessions could be divided into two distinct gene pools, indicating the presence of independent genetic diversity ecotypes. By coupling genome-wide association studies with analyses of genotype variation patterns and expression patterns, we identified several candidate loci and dominant genotypes associated with mango flowering capability, fruit weight, and volatile compound production. In conclusion, our study offers valuable insights into the genetic differentiation of mango populations, paving the way for future agronomic improvements through genomic-assisted breeding.

Spongy tissue, as one of internal flesh breakdown in mango fruits, is correlated with calcium (Ca) deficiency, and adversely affects fruit quality and yield worldwide. However, the underlying mechanism causing spongy tissue remains unknown. Here, we explored the effects of Ca deficiency on spongy tissue in a susceptible cultivar, ‘Keitt’, at the physiological and molecular levels. Nutrient analysis showed that flesh with spongy tissue had lower Ca content and higher N/Ca, K/Ca and Mg/Ca rations than healthy fruit flesh. Ca accumulation in the cell wall, especially in chelator-soluble pectin, was elevated due to increased pectin content, lower levels of pectin methylesterification, and increased pectin methylesterase (PME) activity. During spongy tissue development, levels of Ca oxalate (CaOx) and oxalic acid both increased, whereas soluble Ca content decreased in the flesh. Transcriptomic analysis of healthy flesh and flesh with spongy tissue revealed 2054 up-regulated and 996 down-regulated genes. Gene ontology term analysis showed that the up-regulated genes were mainly enriched in functions related to the transmembrane transporter activity, calcium ion binding, and the cell wall. Importantly, up-regulated genes in spongy tissue included five glucuronate 4-epimerase (GAE) genes and two galactosyltransferase (GALT) genes, which involved in pectin synthesis; four PME genes which control pectin demethylesterification; and eight autoinhibited calcium-transporting ATPase (ACA) genes and two vacuole H+/Ca2+ exchanger (CAX) genes which contribute to Ca influx in the vacuole. Our findings illustrate a mechanism by which Ca deficiency leads to spongy tissue, which will contribute to efforts to control this physiological disorder.

以柁果'金煌'×'热农1号'的F1代54个单株为材料,对其果实性状进行观测,并对单果质量等9个数量性状进行了遗传分析,对30个数量性状和描述性状进行了Shannon-Weaver多样性和主成分分析.结果 表明,9个数量性状(单果质量、果实纵径、横径、侧径、果形指数、可溶性固形物、可食率、果核长度和果核质量)在后代中的遗传符合正态或偏正态分布,变异系数在7.98％ ～ 41.73％之间,多样性指数在1.65～2.04之间,遗传传递力在84.74％ ～ 117.00％之间,果实大小等性状呈趋中变异趋势,可溶性固形物呈超亲遗传趋势.21个描述性状的多样性指数在0.16～ 1.48之间.主成分分析发现前10个主成分的累积贡献率为75.19％,并筛选出单果质量、抗性、果形指数、果皮光滑度、果肉纤维长度、果核表面特征、果实风味、可溶性固形物、胚类型和果肉颜色作为评价杂交后代果实的主要性状.基于观测数据建立了杧果杂交后代果实性状综合评价模型,并利用该方法结合田间观察和实际观测结果筛选出8个优异的单株.

Internal flesh breakdown (IFB), a serious physiological disorder of mango fruit, causes significant economic losses in Southwest China. We investigated the extent of IFB in 100 mango orchards and how changes in the mineral nutrients of fruit flesh, leaves and soil affect IFB. We found that 76% of the mango orchards showed IFB symptoms, and the average IFB incidence was 10%. Fruit flesh with IFB showed higher average contents of N, P, K and Mg, lower average Ca content and higher average ratios of N/Ca, K/Ca and Mg/Ca. The leaves from orchards with IFB symptoms exhibited a remarkable increase in the average N and Mg contents. No significant difference was observed in the soil nutrient concentrations between orchards with and without IFB fruit. IFB incidence was significantly positively correlated with the N/Ca, K/Ca and Mg/Ca ratios in the fruit flesh. However, when considering individual orchards with IFB symptoms, fruit flesh that exhibited breakdown symptoms had Ca content higher, lower than or equal to that of the healthy fruit flesh. There was a strong correlation between fruit flesh and leaf in the same mineral elements, but neither of them showed a significant correlation with soil. Considering the mango trees were cultivated on steep slopes, and fertilizer was applied at a fixed position, we hypothesized that long-term fertilization in the partial root zone led to the excess of N, K and Mg in soil, which reduced the total flesh Ca content or resulted in the abnormal cellular distribution of Ca in the flesh, and ultimately triggered IFB development.

以果肉溃败病果率不同的13个凯特果园果实为材料,研究了正常果和病果果肉中氮、钾、镁和钙含量变化,及不同形态钙含量变化.结果表明,与正常果相比,病果中氮、钙和镁含量,及镁/钙均显著增加,而钾含量、氮/钙、钾/钙和(钾+镁)/钙均无显著变化.果肉溃败病果率与病果中氮、钾、镁和钙含量,及氮/钙、钾/钙、镁/钙和(钾+镁)/钙之间均不存在显著相关性.与正常果比较,病果中结构钙含量显著增加,水溶性钙含量显著降低.果肉溃败病果率与病果中结构钙含量显著正相关,与草酸钙含量显著负相关.由此推测,凯特杧果肉发生溃败可能与果肉组织细胞水平钙分配不均有关.

[目的]营养元素的合理供应是实现芒果优质高产的基础,研究芒果果实生长发育期大量元素和中微量元素的需求规律,确定芒果合理施肥时间和用量,为芒果的科学精准施肥提供依据.[方法]在攀枝花市仁和区芒果优势种植区选择盛果期的台农1号(15年生)作为试验材料,研究果实发育成熟过程中整个果实矿质元素N、P、K、Ca、Mg、Cu、Zn、Fe、Mn含量及其积累量的变化规律.[结果]花后7～77 d,N、K、Mg、Cu、Zn、Fe、Mn含量分别降低59.55％、38.72％、39.75％、73.85％、82.49％、77.71％和49.50;花后77～105 d,各元素含量相对稳定或小幅降低.花后7～35 d,果实Ca含量增加56.85％,然后表现出下降趋势.整个果实生长发育期,果实P含量相对稳定.从幼果期至果实采摘期,果实中各营养元素积累量逐步增加.除Mn外,其他元素均以果实快速膨大期(花后35～77 d)吸收量为主,占总吸收量的64.38％～74.94％.在整个果实生长发育期间,N/Ca、K/Ca和Mg/Ca整体上均表现出降低趋势;花后7～77 d K/P比值先增加后下降.[结论]果实快速膨大期是芒果果实养分需求的最大期,也是补肥的关键期.

以保存于中国热带果树种质资源圃的21?份杨桃种质为材料,利用方差分析、相关性分析和主成分分析法对果实形态和糖、酸、矿质营养含量等25?项品质性状进行了遗传多样性评价.结果表明:21?份杨桃种质果实品质性状存在明显差异,具有丰富多样性;酒石酸含量变异系数最大(109.95％)、其次为铁含量(104.78％)、柠檬酸含量(79.07％)和总酸含量(73.54％),而果实纵径和可溶性固形物含量的变异系数最小,分别为9.97％和7.44％;一些果实品质性状间存在着显著的相关性;主成分分析结果显示前6?个主成分累积方差贡献率为81.63％,各性状的贡献率分散,性状变异具有多向性.

为明确攀枝花市成龄芒果园土壤养分状况,科学指导施肥,本研究对43个芒果园土壤(0～40 cm)进行采样,测定分析了土壤pH、有机质、速效养分和微量养分的含量.结果表明:研究区内13种肥力指标变异系数在0.13～0.75之间,均属于中等变异强度.经取样数合理性统计分析,评价芒果园土壤肥力的43个样本数能够满足90％置信水平下20％相对误差的精度需求.采用主成分分析法和隶属度函数法结合雷达图评价单因素肥力指标在土壤中的状况,结果表明,pH、碱解氮、速效磷、有效铁和有效锌是影响土壤肥力水平的限制性因子.研究区土壤肥力综合指数(IFI)范围为0.25～0.93,平均值为0.55,果园之间IFI的差异较大.

Despite abundant published research on the volatile characterization of mango germplasm, the aroma differentiation of Chinese cultivars remains unclear. Using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS), the composition and relative content of volatiles in 37 cultivars representing the diversity of Chinese mango germplasm were investigated. Results indicated that there are distinct differences in the components and content of volatile compounds among and within cultivars. In total, 114 volatile compounds, including 23 monoterpenes, 16 sesquiterpenes, 29 non-terpene hydrocarbons, 25 esters, 11 aldehydes, five alcohols and five ketones, were identified. The total volatile content among cultivars ranged from 211 to 26,022 μg/kg fresh weight (FW), with 123-fold variation. Terpene compounds were the basic background volatiles, and 34 cultivars exhibited abundant monoterpenes. On the basis of hierarchical cluster analysis (HCA) and principal component analysis (PCA), terpinolene and α-pinene were important components constituting the aroma of Chinese mango cultivars. Most obviously, a number of mango cultivars with high content of various aroma components were observed, and they can serve as potential germplasms for both breeding and direct use.

以53个杧果品种的套袋果实为试材,测定其10个矿质元素含量,运用因子分析和聚类分析等统计方法对矿质元素含量特征进行分析。结果表明,不同品种果实中矿质元素含量存在显著差异,10种元素平均含量依次为:K＞P＞Mg＞Ca＞Na＞Mn＞Fe＞Zn＞Cu＞B,变异系数在16.79%（P）~52.28%（Mn）之间;各矿质元素含量均服从正态分布;Mg与Mn、Zn、Cu、P、K、B之间,Zn、Cu、K两两之间,P与K之间均呈显著正相关;K、P、Ca、Mn和B是杧果果实的特征矿质元素;53个品种可以分为4类:（1）高K、P、Mg、Zn和Cu含量的品种11个,（2）高Na和Fe含量的品种18个,（3）低Mg、Zn和K含量的品种8个,（4）低Ca、B和Mn含量的品种16个。