Genome wide association analysis identifies candidate genes for fruit quality and yield in Actinidia eriantha

Quality and yield are the primary concerns in kiwifruit breeding,but research on the genetic mechanisms of fruit size,shape,and ascorbic acid(ASA)content is currently very limited,which restricts the development of kiwifruit molecular breeding.In this study,we obtained a total of 8.88 million highly reliable single nucleotide polymorphism(SNP)markers from 140 individuals from the natural hybrid offspring of Actinidia eriantha cv.‘White’using whole genome resequencing technology.A genome-wide association study was conducted on eight key agronomic traits,including single fruit weight,fruit shape,ASA content,and the number of inflorescences per branch.A total of 59 genetic loci containing potential functional genes were located,and candidate genes related to single fruit weight,fruit length,ASA content,number of inflorescences per branch and other traits were identified within the candidate interval,such as AeWUSCHEL,AeCDK1(cell cycle dependent kinase),AeAO1(ascorbic oxidase)and AeCO1(CONSTANS-like 4).After constructing an RNAi vector for AeAO1 and injecting it into the fruit of cv.‘Midao 31’to interfere with the expression of the AeAO1 gene,the results showed that the activity of ascorbic oxidase in the fruit of‘Midao 31’significantly decreased,while the content of ASA significantly increased.This study provides valuable insights into the genetic basis of variation in A.eriantha fruit traits,which may benefit molecular marker-assisted breeding efforts.

Dynamic Variation in Sugar,Acid,and ASA Contents of ‘Ganmi 6' Kiwifruit(Actinidia eriantha Benth) Fruits

[Objective] The variation of sugar, acid and AsA contents in fruits of ‘Ganmi 6＇ kiwifruit （Actinidia eriantha Benth） were investigated during fruit develop- ment. [Method] Kiwi fruits were randomly taken as materials every 15 days since 20 days after full bloom （DAFB） to 170 DAFB until in mature stage. [Result] The results showed that during fruit development of ‘Ganmi 6＇, the total sugar soluble contents had a rising trend with relatively stable at 95 DAFB, then rose until har- vest with the maximum content （10.35%）. The titratable acid content showed a trend of increasing, then declining, then increase to the harvest content （1.10%）. From the sugar acid ratio, we can knew it decreased in 95 DAFB, then up to the max （9.38）. The changes of AsA contents showed double ‘S＇ shape, decreased af- ter the first increased rapidly, slightly increased and then decreased in the early harvest. [Conclusion] It provided a theoretical basis for scientific cultivation methods to explore the nutrients regulation.

A high-quality genome of Actinidia eriantha provides new insight into ascorbic acid regulation

Actinidia eriantha is one of the species of kiwifruit with a particularly high ascorbic acid (AsA) content.However, the molecular mechanism driving AsA richness in fruit remains unclear.In order to reveal the molecular mechanism of AsA richness in A. eriantha, this study constructed a regulatory network related to AsA metabolism by combining genomics,metabolomics and transcriptomics.We assembled a high-quality genome of A. eriantha ‘Ganlv 1’ with only five remaining gaps.The assembly is comprised of 29 pseudochromosomes with a total size of 615.95 Mb, and contig N50 of 20.35 Mb.Among them,24 of the pseudochromosomes were obtained directly from telomere-to-telomere.The LTR assembly index score and consensus quality value were 21.34 and 39.90%, respectively.Subsequently, 61 metabolites and 2 092genes were found to be differentially accumulated/expressed during fruit development by metabolome and transcriptome assays, respectively.AsA metabolism and the cyclic regeneration pathway were found to have high expression levels throughout fruit growth and development,suggesting its crucial role in the regulation of AsA.Furthermore,the AsA contents are highly associated with ascorbate peroxidase genes.The genome obtained in this study provides genomic resources for the genetic and breeding research ofA. eriantha, and the constructed regulatory network can provide a public data platform for future research on kiwifruit.

Effects of Stored Pollens from Wild <i>Actinidia eriantha</i>Vines on Some Fruit Quality Traits

Our study was conducted to determine In vitro germination ability of pollens from 25 wild Actinidia eriantha genotypes after one year freeze storage, afterwards we examined fertilization ability of stored pollens of 8 genotypes selected according to In vitro test results from aforementioned 25 genotypes, and finally investigated effects of stored viable pollens from “MH67”, “MH55”, “MH48” and “MH45” genotypes on fruit quality characters of the female experimental plant “M3” as the main purpose. Non-pollinated “M3” kiwifruit plant was taken as control. We found that In vitro germination and fertilization ability of different stored pollen sources, and also fruit quality characters including dry matter, total sugar, titratable acid, vitamin C, total polyphenol, total flavonoid, chlorophyll (“a”, “b”, and total) and carotenoid contents except total soluble solid content were significantly different. MH67 and MH45 genotypes were evaluated as the most suitable pollenizers which can be recommended as new candidate cultivars because of long term storage ability and brought about desired fruit quality characters. They also will be investigated more at further breeding studies.

Influence of Storage Time on Pollen Traits in Actinidia eriantha

We examined the influence of storage time on germinability and tube growth of freeze stored pollens collected from 25 wild male plants in Actinidia eriantha variety. Pollens were stored in freezer at - 20°C for six months and one year periods to determine changing at germinability in time. In vitro germination was conducted in certain cultural medium defined for Actinidia genus. The results showed that the germination percentages and tube lengths of genotypes decreased at the end of storage period. MH22, MH45, MH47, MH56, MH67, MH70, MH71, MH72, MH74, MH55 and MH61 genotypes were evaluated as vigor genotypes, because they maintained their viability and germination capability displaying statistically insignificant decreasing although their tube lengths significantly decreased except MH67. This investigation provided to determine some robust wild male germplasm resources in A. eriantha in point of durability of pollens against long term conservation for using at future pollination and breeding programs.

甜香型毛花猕猴桃新品种赣绿1号的选育

赣绿1号系从野生毛花猕猴桃(Actinidia eriantha Benth.)自然变异群体中选育而成的新品种。果实长圆柱形至长卵圆形,果喙微钝凸,果面密被白色短茸毛。果实大小中等,均匀一致,平均单果质量为46.22 g,最大单果质量为73.50 g。果肉翠绿,肉质细嫩,风味香甜,果实可溶性固形物含量(w,后同)为18.4%~22.2%,可滴定酸含量为0.94%,可溶性糖含量为9.25%,干物质含量为21.74%,抗坏血酸含量为662.6 mg·100 g^(-1)。在江西省宜春市,盛花期为5月上旬,果实成熟期为10月底至11月上旬。植株树势较强,耐热抗旱,适应性强,果实均匀一致,富含抗坏血酸,易剥皮,鲜食品质佳,果实耐贮藏,常温下可贮藏30~50 d,综合性状优良。

毛花猕猴桃新品种“赣绿1号”的生物学特性及关键栽培技术

以毛花猕猴桃“赣绿1号”为研究材料,“赣猕6号”(相似品种)为试验对照,对其主要生物学特性进行了系统观测与分析,探明该品种的生长发育规律,以期为制定合理的栽培管理措施提供理论依据。研究表明,在江西省宜春市奉新县地区,“赣绿1号”伤流期在2月上中旬,初花期在5月上旬,终花期在5月中旬,果实成熟期在10月下旬,为晚熟二倍体品种;“赣绿1号”成叶长卵圆形,叶面无茸毛,花为伞房花序,每花序单花3~5朵,花瓣粉红色,花药淡黄色;“赣绿1号”果实近圆柱形至长卵圆形,平均单果质量46.5 g,果形指数为2.52,果实软熟时可溶性固形物含量19.40%,最高达22.20%,干物质含量21.75%,可溶性糖含量为9.25%,可滴定酸含量为0.94%,抗坏血酸含量为662.6 mg/100 g,果肉呈墨绿色,肉质细嫩,风味甜香。“赣绿1号”植株树势较强壮,耐热抗旱,适应性强,果实富含抗坏血酸,易剥皮,综合性状优良且遗传性状稳定。“赣绿1号”在无霜期130 d以上、≥10℃积温达1500℃以上的地方均可栽培,宜选择海拔1000 m以下,pH值6.0~7.0,土壤疏松肥沃、有机质含量丰富、灌溉方便的砂壤土建园。成龄果园一般每年施肥2~3次,萌芽肥以N肥为主,壮果肥以P、K、Ca肥为主,秋季基肥以有机肥为主。架式宜采用水平大棚架或T型小棚架,株行距(2.5~3.0)m×(3.5~4.0)m,雌雄株比例为(6~8)∶1。蕾期及时“零芽”折梢修剪,幼果期及时疏果与套袋。采用单干双主蔓多侧蔓整形方式,冬季修剪时可采用中长蔓修剪法,短截、疏删与回缩相结合。

毛花猕猴桃赣绿1号果实留树后熟期间品质动态变化与评价

[目的]毛花猕猴桃赣绿1号具有生理成熟后不易落果的特性。探明其果实留树后熟期间的品质变化,为猕猴桃的留树后熟技术应用提供理论基础。[方法]以毛花猕猴桃赣绿1号品种为研究对象,从果实生理成熟期开始,每隔10 d随机采集果实,直至果实皱缩不宜食用。果实运回实验室后立即测定其果实外观及内在品质指标。最后利用主成分分析法对赣绿1号果实品质进行综合评价,筛选最佳留树时间。[结果]赣绿1号果实留树后熟期间,单果质量和硬度呈下降趋势,分别下降了23.72%和90.51%;抗坏血酸、可滴定酸、可溶性固形物、可溶性糖及各色素含量均呈现先增后降的趋势。其中,抗坏血酸与可滴定酸含量(w,后同)在盛花后192 d达到峰值1282.22 mg·100 g^(-1)、1.26%;可溶性固形物与可溶性糖含量在盛花后210 d达到峰值18.41%、10.87%;盛花后210 d各色素含量迅速下降。通过主成分分析综合评价:盛花后192~210 d的果实品质最佳。[结论]赣绿1号果实留树后熟期间,果实外观指标均呈现下降趋势,内质品质呈现先增后降趋势,留树21~39 d的果实综合品质最佳。

毛花猕猴桃成熟期果实品质和蔗糖代谢特征分析

[目的]探究果实成熟期可溶性糖含量差异大的原因,以挖掘毛花猕猴桃果实蔗糖代谢关键酶和关键基因。[方法]以高糖型赣绿1号和低糖型赣绿6号毛花猕猴桃品种为研究材料,测定果实生理成熟期外观指标;测定软熟期可溶性固形物含量、干物质含量、可溶性糖含量、糖组分含量、甜度值、蔗糖代谢酶活性和代谢酶基因相对表达量等指标;分析不同指标间的相关性。[结果]果实成熟期可溶性糖含量与蔗糖含量呈显著正相关;蔗糖含量与蔗糖磷酸合酶活性及其编码基因AeSPS表达量呈显著正相关。[结论]蔗糖是引起毛花猕猴桃果实可溶性糖含量差异大的主要原因,蔗糖磷酸合酶是影响果实成熟期蔗糖代谢的关键酶,推测其编码基因AeSPS是调控果实成熟期蔗糖合成的关键基因。

毛花猕猴桃雌雄花的形态特征比较与杂交授粉研究

通过对毛花猕猴桃花形态及开花动态等繁育系统相关特征进行研究,同时与中华猕猴桃和美味猕猴桃进行杂交授粉,比较杂交果实单果重量、果形指数、糖度等特征。研究结果表明:毛花猕猴桃雄花花期略晚于雌花,单花花期6~8 d,种群花期10~12 d;雌花显著大于雄花,雌花开度(47.77±3.14) mm,雄花开度(33.25±1.82) mm;雄花雄蕊显著多于雌花,为雌花的1.67倍;雌花的胚珠数(1 573±118)枚,不存在无融合生殖现象。以毛花猕猴桃雌株为母本,与美味猕猴桃和中华猕猴桃杂交授粉后单果重量大于对照组,并且单果重量、果实的糖度、种子数等与对照组相比均具有显著差异。以毛花猕猴桃雄株为父本,与中华猕猴桃雌株杂交授粉结实率较高,与美味猕猴桃则不能结实。因此,用中华猕猴桃和美味猕猴桃的花粉对毛花猕猴桃进行授粉能显著提高的果实重量。

毛花猕猴桃雄株“N124”选育初报

“N124”是从毛花猕猴桃实生后代中选育的雄性优系。该优系树势较强,花多为双歧聚伞花序,单花花朵大,花瓣主色为淡粉红色,花瓣基部粉红色,花丝粉红色,花药黄色,观赏性高;花粉萌芽率高达72%,单枚花药花粉量达6.0×10^(4)个。在湖北省咸宁地区,“N124”5月初开花,花期长达20 d。

10份大果型毛花猕猴桃种质果实品质分析与综合评价

为筛选出优良的大果型毛花猕猴桃种质资源,以10份大果型毛花猕猴桃种质的果实为材料,测定单果质量、果形指数、维生素C、可溶性固形物、可滴定酸等6个主要果实品质性状,进行变异分析、主成分分析和综合评价。结果表明:维生素C含量变异系数最大(22.50%),可溶性固形物含量变异系数最小(11.37%);主成分分析结果,前4个主成分方差累积贡献率为95.09%,其中第1主成分的特征值为2.69,贡献率为44.87%,主要由固酸比、维生素C、可溶性固形物含量和可滴定酸含量决定。根据提取前4个主成分计算果实品质综合评价得分,BC1种质和BC9种质综合得分值大于1,果实品质综合表现较好,特别是BC1种质具有高维生素C特点,可作为种质创新和育种资源利用。

中华猕猴桃和毛花猕猴桃果实碳水化合物及维生素C的动态变化研究

分别对中华猕猴桃(Actinidia chinensis)黄肉品种‘金桃’和毛花猕猴桃(Actinidia eriantha)品系‘6113’果实生长发育过程中碳水化合物及维生素C的动态变化进行了系统研究。结果表明,中华猕猴桃‘金桃’和毛花猕猴桃‘6113’果实的可溶性固形物(SSC)含量均于谢花后146d内保持相对平稳,而后开始上升;此时,两物种果实的淀粉含量均上升到最大值,之后两者均开始下降。两者糖含量的变化与SSC相似,且中华猕猴桃‘金桃’果实糖含量进入快速增长期的时间比毛花猕猴桃‘6113’早1个月。两者果实Vc含量的变化趋势相似,均于7月上中旬达到一个高峰,以后随着果实的生长发育,含量下降,‘金桃’于8月14日降至最低值,‘6113’于9月13日降至最低值;两者的Vc含量降到最低值后均缓慢上升,到果实完全成熟期(树上自然软熟期)回升到第二个峰值。‘6113’果实的Vc含量在完全成熟期的峰值远远高于7月上旬的高峰值。对‘金桃’和‘6113’果实碳水化合物及Vc含量方差分析表明,两者的可溶性固形物、淀粉和总糖没有明显差异,而毛花猕猴桃‘6113’的Vc含量显著高于中华猕猴桃‘金桃’。

猕猴桃种间杂交新品种‘金艳’的果实发育特征

【目的】研究种间杂交品种‘金艳’及其母本毛花猕猴桃品系‘6113’和中华猕猴桃品种‘金桃’果实生长发育特征。【方法】以国家猕猴桃种质资源圃(武汉)保存的种间杂交品种‘金艳’、父本中华猕猴桃雄株对应的雌性品种‘金桃’和母本毛花猕猴桃品系‘6113’为试验材料,定期检测果实发育过程中的单果质量、硬度、可溶性固形物、淀粉、还原糖、总糖和总酸的含量,运用Excel对结果进行分析。【结果】‘金艳’果实单果质量的变化与毛花猕猴桃‘6113’果实的相近,呈现3-4次增长高峰,而中华猕猴桃‘金桃’果实单果质量变化呈典型的双"S"型曲线;‘金艳’与2亲本果实的硬度和酸含量总体趋势是前期增加,后期下降,只是‘金艳’和毛花猕猴桃‘6113’果实的硬度整个发育中有3个明显的峰值,而中华猕猴桃‘金桃’只有2个峰值;‘金艳’果实的可溶性固形物、还原糖、可溶性总糖的含量变化曲线与两亲本相同,前期趋于稳定,至成熟前的2个月开始进入迅速增加阶段;‘金艳’和2亲本一样,均于谢花后约55 d果实开始积累淀粉,‘金艳’于谢花后165 d达最大值,而中华猕猴桃‘金桃’和毛花猕猴桃‘6113’均于谢花后155 d达到最大值,以后迅速下降,回落到谢花后55 d的水平;比较同一品种果实的淀粉和可溶性固形物、总糖等的变化,显示了2者的消长关系,在淀粉前期积累阶段,可溶性固形物和糖含量变化小,而到淀粉后期降解阶段,可溶性固形物、总糖等的含量迅速上升。【结论】种间杂交品种‘金艳’果实生长发育变化更偏向母本毛花猕猴桃‘6113’;而果实质量远超过母本毛花猕猴桃‘6113’,酸含量远低于毛花猕猴桃‘6113’和中华猕猴桃‘金桃’,具有典型的超亲效应。

大果毛花猕猴桃新品种‘华特’

‘华特’猕猴桃是从野生毛花猕猴桃中选育出的新品种,单果质量82～94g,是野生种的2～4倍,最大132.2g。可溶性固形物含量14.7%,可滴定酸含量1.24%,维生素C含量6.28mg·g-1。

野生毛花猕猴桃叶片与果实AsA含量变异分析

以江西省武功山境内的野生毛花猕猴桃(Actinidia eriantha Benth)种质资源为试材,对随机采集的70份不同植株的野生毛花猕猴桃成熟叶片和幼嫩果实的AsA(抗坏血酸)含量进行了测定与分析,旨在发掘毛花猕猴桃优异种质,为野生毛花猕猴桃资源的合理开发利用及探讨AsA积累机制提供理论依据。结果表明,供试的野生毛花猕猴桃成熟叶片和幼嫩果实的AsA含量存在丰富的变异,成熟叶片AsA含量变异系数为41.30%,幼嫩果实AsA含量变异系数为21.88%。经变异分析和方差分析,筛选了8份高果实AsA含量(17.00 mg/g以上)的野生毛花猕猴桃优异种质。

野生毛花猕猴桃雄花花器性状及SSR遗传多样性研究

【目的】研究江西省内野生毛花猕猴桃雄性种质的多样性。【方法】对江西省野生毛花猕猴桃雄性种质资源开展调查和收集,分析花器表型性状变异和SSR遗传多样性。【结果】供试68份毛花猕猴桃雄性种质的雄花花器在表型性状和DNA分子水平上均存在明显的变异和较丰富的遗传多样性,表型性状平均变异系数为29.19%,其中变异幅度最大的为花粉量(53.41%),最小的为花冠直径(15.47%)。通过表型聚类分析,可将该68份种质资源分为两大类群,类群A可分为2个亚类,大部分样品聚为第1亚类,主要表现为花梗较短,花冠较大,花粉活力较高,花冠颜色为粉红;第2亚类总体表现为花梗较长,花冠较小,花粉活力中等。类群B仅有2份样品,其特征为花冠大、雄蕊数多和高花粉量,在DNA分子水平上,筛选到的15对SSR有效引物共扩增出87个等位位点,均为多态性位点。Shannon’s信息指数为1.04,多态信息含量为46.48%。UPGMA聚类分析可将供试种质材料分为3类。2种聚类结果相似,Mantel分析中表型性状与分子标记结果呈显著相关(r=-0.79,p<0.05),SSR分子标记在一定程度上反映了不同毛花猕猴桃雄性种质表型性状的变异情况。【结论】68份野生毛花猕猴桃雄性种质表现出较丰富的遗传多样性。其中花粉量、单花雄蕊数、花粉活力、花瓣颜色、花丝颜色、花梗长度是造成表型性状差异的主要因素。SSR分子标记分析与毛花猕猴桃花器表型聚类结果具有显著相关性,毛花猕猴桃雄花的多种表型性状是环境和基因共同作用的结果。

野生毛花猕猴桃果实品质主成分分析及综合评价

为构建毛花猕猴桃果实品质评价体系,利用DPSS软件对野生毛花猕猴桃可溶性糖、可滴定酸、维生素C、可溶性固形物等品质指标进行主成分分析。结果表明,果实变异系数差异明显,其中可溶性糖变异系数最大,达41.34%;主成分分析表明,将6个品质指标综合成3个主成分因子,可代表野生毛花猕猴桃果实品质的82.629%的信息量;综合评价结果表明,59、13、14、12、55、4、60、15、57、25、58号样品野生毛花猕猴桃果实品质优异,41、45、21、20、53、34、22、32号样品野生毛花猕猴桃果实品质较差。本研究对收集的野生毛花猕猴桃果实品质进行分析,找到了果实品质综合评价的3个主成分,揭示了不同野生毛花猕猴桃果实品质的差异。

野生毛花猕猴桃雄株居群花粉形态观察

【目的】分析江西省麻姑山自然保护区内野生毛花猕猴桃花粉的形态特征,了解其遗传变异性、亲缘关系与演变规律。【方法】利用扫描电子显微镜对23个野生毛花猕猴桃雄株的花粉粒进行了形态观察。【结果】毛花猕猴桃雄株花粉粒外观为长球形,偶有近超长球形;极面观为三裂圆形,极轴长22.42～27.73μm,变异系数为4.75%;赤道轴长12.73～14.31μm,变异系数为3.12%。具3萌发沟,赤道面可见1～2条,等间距分布,萌发沟长20.52～24.68μm,变异系数为5.11%;萌发沟脊宽7.29～9.52μm,变异系数为6.78%;根据NPC分类系统分类,属于N3P4C5型花粉。花粉外壁纹饰有3种类型：脑纹状、波纹状和疣状纹饰,分别占花粉样品的65.22%、30.43%和4.35%。聚类分析结果显示,多数雄株亲缘关系较近。【结论】该居群内野生毛花猕猴桃雄株花粉的形态有较多的共性特征,同时在花粉的形态、外壁纹饰上,不同单株间存在差异,分别呈现毛花猕猴桃的遗传保守性和多样性。花粉外壁纹饰的演化趋势为：由波纹状向疣状和脑纹状演化。

毛花猕猴桃原生质体再生植株

从毛花猕猴桃（Ａｃｔｉｎｉｄｉａ ｅｒｉａｎｔｈａ Ｂｅｎｔｈ．）试管培养的实生苗新展开叶片分离的原生质体，培养在液体ＭＳ（除去ＮＨ４ＮＯ３）附加２，４－Ｄ １．０ ｍ ｇ／Ｌ和葡萄糖０．４ ｍ ｏｌ／Ｌ的培养基上。培养３周后植板率达到１９．４％ 。在未添加新鲜培养基的情况下，原生质体再生的细胞可持续分裂，并于３个月时长成２ ｍ ｍ 大小的愈伤组织。将该愈伤组织转移到附加玉米素０．５ ｍ ｇ／Ｌ和ＩＡＡ ０．１ ｍ ｇ／Ｌ的固体ＭＳ培养基上，分化出苗。试管苗经诱导生根。