苹果柱型基因的ISSR分子标记研究

 以普通型苹果品种‘富士’和柱型苹果‘舞姿’以及其杂交后代的柱型与非柱型实生苗为试材, 建立了苹果的ISSR ( Inter-Simple Squence Repeat polymorphic DNA) 分子标记体系, 并将ISSR 标记用于苹果柱型基因Co 的遗传分析。结果表明, 在20μL 反应体系中各组分的用量为Taq DNA 聚合酶1U、Mg²⁺ 的浓度为2.5 mmol·L^-1 、模板DNA 用量20 ng、引物浓度0.2μmol·L - 1及退火温度52 ℃, 80 %引物具有良好的扩增能力。调整模板DNA 的用量、引物浓度及退火温度能够优化苹果ISSR-PCR 扩增体系。从所筛选的65 个引物中获得了35 个ISSR 标记, 其中33 个标记呈现1∶1 分离, 可用于苹果柱型基因的遗传分析。     

苹果基因组分子生物学研究进展

借助分子标记手段苹果基因组研究取得了巨大成就,涉及苹果的抗性、生长发育、果实品质等各方面基因,综合有关文献,将其研究的主要成果,包括已发现的主要苹果遗传标记、已构建的苹果遗传连锁图谱及苹果的转基因研究进行综述,并对目前苹果基因组研究存在的问题和对策进行了分析,以期为苹果遗传育种提供参考。     

柱型苹果引种研究

在山东省的自然条件下进行了柱型苹果引种试验。结果表明,3个柱型苹果品种生长结果正常,表现出典型的柱型生长习性。柱型苹果与生产上常见品种的花期相遇,可以互为授粉树。利用M_(26)和M_9矮化中间砧可有效地控制树体高度和侧梢的产生,促进成花和结果。不同砧木或中间砧对柱型苹果果实的品质性状有一定的影响。在高度密植(0.6m×1.0m)条件下,1年生和2年生柱型苹果即可获得较高的产量。在供试的3个品种中,以特拉蒙综合表现较好。杂交试验表明,柱型性状是由单个显性基因(Co基因)控制的,利用现有的柱型苹果品种作为亲本选育新的柱型苹果品种是可行的。     

桃主要性状的分子标记与功能基因定位研究进展

综述了桃果实、花、树体及抗根结线虫等主要性状的功能基因定位和分子标记开发的最新研究成果,阐述了决定果皮茸毛有无、果肉颜色(黄/白)、果肉质地与核黏离性、短枝型矮化和柱型等质量性状的功能基因定位,分析了1个与成熟期主效位点相关的重要候选基因,同时对决定果实糖、酸含量变化的QTL以及根结线虫(Meloidogyne incognita)、蚜虫(Myzus persicae Sulzer.)抗性相关位点的研究进展进行总结,为桃性状定位和整个发育期调控糖、酸含量的基因及其作用模式研究提供参考。在此基础上,对功能基因和分子标记在辅助选择育种和种质资源鉴定中的应用及发展方向进行展望。     

基于CAPS标记的沙梨果实乙烯释放量水平的快速鉴定

沙梨果实贮藏性能与其乙烯释放量相关。基于ACS(1-氨基环丙胺-1-羧酸合酶)基因PPACS1(A)、PPACS2(B)建立一套CAPS分子标记体系,对15个沙梨品种的ACS基因型进行鉴定,并与果实成熟后的乙烯释放量进行关联分析。结果表明,不同沙梨品种基于CAPS分子标记鉴定的ACS基因分型结果与其果实成熟后乙烯释放量状况吻合,AB型品种乙烯释放量最高,其次为Ab型,再次为aB型,A、B均缺乏的ab型(鄂梨2号等5个品种)乙烯释放量最低、显示为非呼吸跃变型特征。该分子标记体系可用于沙梨品种的贮藏性鉴定和耐贮藏沙梨育种中的早期辅助选择。     

苹果柱型基因Co的一个AFLP 标记的SCAR转换

 将苹果柱型基因的一个AFLP 标记成功地转换成了简单实用的SCAR 标记。首先对AFLP 标记片段进行序列测定, 然后根据序列特点设计了两对特异引物CoA1/ CoA2 和CoA1/ CoA3 , 每条引物长20 bp。PCR 结果表明CoA1/ CoA2 可以扩增出216 bp 和148 bp 两条带, 其中216 bp 的为柱型性状的特征带; CoA1/CoA3 可以扩增出273 bp 和205 bp 的两条带, 其中273 bp 的为柱型性状的特征带。两对引物在杂交后代中扩增出的特征带与柱型性状的分离重组率都很低(CoA1/ CoA2 为6. 3 % ±2. 5 %; CoA1/ CoA3 为7. 3 % ±2. 6 %) , 所以它们都可以作为该SCAR 标记的特异引物所用。     

苹果果实酸/低酸性状的SSR分析

 以91株‘东光’和‘富士’的正反交F₁ 代群体为试材, 测定了成熟果实可滴定酸含量和果实不同发育阶段苹果酸含量的变化, 从表型上分析了苹果酸的遗传规律。利用140对共显性遗传的SSR引物对高酸和低酸个体群体分离分析, 筛选到一个与果实酸/低酸性状连锁的标记SDY085, 遗传距离为8.89 cM, 表型分析和标记分析都表明苹果果实酸/低酸性状由一对主效基因Ma/ma控制, 并且Ma对ma为完全显性, 而酸个体中苹果酸的连续分布则是加性多基因作用的结果。     

梨遗传连锁图谱的构建及部分果实性状QTL的定位

利用八月红梨和砀山酥梨杂交得到的F1代实生苗为作图群体,应用Joinmap3.0作图软件,构建了一张包含61个苹果EST-SSR标记、68个苹果SSR标记、49个梨SSR标记、1个RAPD标记和3个质量性状标记,共182个标记并分属于19个连锁群的梨遗传连锁图谱,图谱总长度为982cM,标记间平均图距5.4cM。控制果皮红色的基因RFS位于LG3连锁群上,与最近的分子标记MES93-264p的遗传距离分别为9cM。控制果锈存在的基因FR、控制萼片脱落性状的基因AS分别位于LG16连锁群和LG12连锁群上。采用区间作图法,检测到与果实可溶性固形物含量、单果质量、横径和纵径等性状连锁的QTL位点21个(LOD≥2.5),其中主效QTL位点6个(LOD≥3.5),与果实性状相关QTL位点多集中在LG7和LG11连锁群上。     

苹果与梨远缘杂交种甘金和甘红果实品质特性评价及分子水平鉴定

【目的】对苹果与梨远缘杂交的优良品种甘金和优系甘红进行果实品质特性评价，并用特异性分子标记鉴定杂交种的真实性，为后期真杂种在抗逆育种研究领域应用提供理论支撑。【方法】对甘金和甘红树体的生长势和果实经济性状进行评价，将苹果金冠和西洋梨巴梨的基因组进行比对，分别筛选苹果和梨中特有的序列，通过设计属间特异性引物对甘金、甘红和亲本的DNA进行扩增。【结果】甘金和甘红树势生长健壮、抗逆性强和果实品质优。特异性引物M1、M2和M3在母本苹果品种中扩增出条带；P1、P2、P3这3对引物只能在父本梨品种中扩增出条带；2对通用引物U1和U2在苹果和梨杂交种中均能扩增出条带。此外，苹果M1、M2、M3和梨P1、P2、P3对杂交后代甘红、甘金进行扩增时，均出现条带，说明杂交后代既有苹果的基因，又有梨的基因。【结论】采用基因特异性分子标记开发的梨和苹果属间的特异性引物，鉴定远缘杂种的真实性，为苹果和梨以及其他果树的属间远缘杂交种的鉴定提供有价值的参考。     

柱型苹果MdGAI基因的克隆及表达分析

以柱型苹果‘鲁加5号’茎尖为试材,克隆编码DELLA蛋白的MdGAI基因,并研究该基因的表达特点。结果表明,柱型苹果MdGAI的cDNA序列长度为2491bp,编码635个氨基酸。核酸序列与其它苹果属植物具有很高的同源性,在N端具有保守氨基酸结构域DELLA和VHYNP,在C端存在保守的氨基酸结构域VHVID和SAW。...     

The effect of selective picking on the harvest fruit size distribution of ‘Royal Gala‘ apples

Summary

The size distribution of fruit on an apple tree on any potential harvest date can be estimated by measuring a sample of fruit early in the season and projecting forward in time using standard growth curves. However, ‘Royal Gala‘ apples grown in New Zealand are picked in multiple harvests spread over about three weeks, so the overall size distribution of harvested fruit can differ significantly from that on any single harvest date. On each havest date, fruit are selected for picking according to background colour, not size. By measuring the sizes at harvest of all fruit on selected limbs of eight ‘Royal Gala‘ trees in Hawkes Bay, New Zealand, we show that the relationship between the size distributions of picked and unpicked fruit can be described by a single-parameter model. Although size is not used directly in fruit selection, we find that larger fruit still tend to be picked first, with the odds of a fruit being selected approximately doubling for each 20.g increase in size. The mean harvest fruit size is largest for the first harvest, and decreases in later harvests, despite ongoing fruit growth. Because the smaller fruit left on the trees continue to grow, the standard deviation of the overall fruit size distribution from multiple harvests can be expected to be significantly smaller than it would have been had all fruit been harvested on the same date. The model is tested using size and background colour measurements collected on tagged fruit at three sites in two years, including a range of shading and crop load treatments. For most combinations of site, year and treatment, the model predicted the size distribution of picked fruit well, but in a few cases a different parameter value was need to obtain a good fit.     

Pre-harvest growth and development,measured as accumulated degree days,determine the post-harvest green life of banana fruit

Summary

We aimed to define a more robust indicator for banana harvest date that ensures an optimal fruit green life (GL). Our hypothesis was that development rather than growth would account for GL more accurately. To this end, five indicators were compared: one related to fruit size (i.e., growth, expressed as the diameter of fruit); two related to fruit age [i.e., development, expressed as the age of fruit measured in the number of days or in degree days (°Cd) from inflorescence emergence]; and two related to metabolism during maturation (i.e., the concentrations of malate and citrate in the pulp). Different treatments (e.g., fruit removal, leaf shading, bunch bagging, defoliation, water deficit, and flooding) were applied to modify the fruit growth rate. On different dates between the emergence of the inflorescence and harvest, fruit GL and the five indicators were measured. The results showed that there was a decreasing exponential relationship between GL and accumulated °Cd from inflorescence emergence (r² = 0.77). This was more reliable than the relationships between GL and fruit diameter (r² = 0.39), or between GL and fruit age, expressed in days (r² = 0.39). Relationships were also established between GL and malate or citrate concentrations, but they were not sufficiently reliable to estimate GL. The results illustrate that GL is related to fruit development, and that °Cd is a more reliable criterion for harvest date than the number of days, or fruit diameter, because it is less sensitive to different fruit growth rates. Banana growers in the French West Indies usually use fruit diameter and age in days to determine harvest date. However, they face problems of fruit ripening during transportation. The use of °Cd as an indicator may help to determine the optimum harvest date more accurately.     

Branch scoring encourages fruit development and climacteric in persimmon

Branch scoring of ‘Rojo Brillante’ persimmon (Diospyros kaki) increased fruit size at harvest and caused a significant shift in the distribution of fruit diameters to the larger sizes, the response magnitude depending on the date of scoring. Scoring at the 75–77 growth stage of the BBCH-scale encouraged the development of fruit which grew faster, reached commercial colour, ripening and flesh softness earlier, and therefore was harvested earlier. Although fruit weight was significantly increased by scoring, the number of fruit was not modified and there was not a significant increase in yield. Fruit from trees scored at the onset of cell enlargement stage initiate ethylene production before fruit from unscored trees. Scoring did not modify following yield.     

Predicting fruit maturation in kiwifruit (Actinidia deliciosa)

Summary

In New Zealand, 6.2% soluble solids concentration (SSC) is the minimum maturity at which kiwifruit destined for export can be harvested. Ambient temperature during the fruit maturation period has been shown to affect the soluble solids accumulation rate. The purpose of the present study was to describe variation in the rate of fruit soluble solids accumulation in different regions and seasons and to develop a means of quantifying the effects of temperature on the rate of fruit maturation. Measurements of fruit SCC were made over a three year period on one orchard in each of six principal kiwifruit-growing regions across New Zealand. The date at which fruit reached 6.2% SSC varied by 34 d across all sites and years. There was an 18 d range in the average date across all sites, with Riwaka, the coolest site being the earliest, and Kerikeri, the warmest site, being the latest. The variation from year to year across all sites was 12 d. We formulated a non-linear, time-dependent model to predict the rate of change of SSC with time, given the temperature and the time since flowering. This model accounted for nearly 60% of the variation in the date that 6.2% SSC was reached and 70% of the variation in the date that 6.5% SSC was reached, if a common initial SSC was assumed across all sites and seasons. No improvement was obtained if the initial SSC was measured about three months after flowering, rather than assumed. A similar model which used the day of year rather than days since flowering was found to be slightly less accurate. However, all three versions of the model performed better than a linear regression model based on mean temperature for the fruit growth period and the date at which 5.0% SSC was reached.     

与苹果柱型基因(Co)相关的AFLP标记片段的克隆

Co基因是与苹果树体生长习性有关的一个主基因，是培育树体紧凑型苹果品种的一个十分重要的基因资源，所以，Co基因分子标记的研究对苹果育种具有重要价值。用PCR的方法将以短枝富士×舞姿的F1分离群体为试材筛选到的一个与Co基因连锁较为紧密的AFLP标记成功地进行了再扩增，同时也实现了此标记片段的克隆和转化。这一研究结果对该AFLP标记向SCAR标记的转换具有重要意义。     

Root growth following defruiting improves peach tree water status

Summary

Tree growth and water status throughout the growing season and after fruit removal were studied in container-grown peach trees. Trees with fruit (F) and defruited (DF) trees were sampled destructively at bud break (8 March), 1 month after fruit removal (3 June), at harvest (6 August), and before leaf fall (15 October) to determine the mass of leaves, current season shoots, branches, trunk, and the entire root system. Tree water status was determined from the mid-day stem water potential (SWP) the day before each sampling date. Root growth in DF trees was greater than that observed in F trees, while the above-ground biomass was similar in DF and F trees. DF trees therefore had lower leaf:root biomass ratios than F trees throughout the fruit growing season. Environmental factors did not fully explain the seasonal variations in SWP, but there was a significant correlation between leaf:root biomass ratios and SWP. Reductions in leaf:root biomass ratios were accompanied by increases in SWP and, ultimately, DF trees had higher SWP values than F trees in mid-Summer. Improvements in tree water status following fruit removal can be explained, in part, by additional root growth.     

抗番茄黄化曲叶病毒耐热番茄新品种农1305的选育

农1305是采用夏季保护地田间高温胁迫鉴定和分子标记方法选育的,以自交系TB123为母本、以N-136为父本配制而成的抗病耐热番茄一代杂种。无限生长类型,生长势较强。在夏季保护地中能正常生长发育,植株茎秆粗壮,不易徒长,田间长势整齐一致,叶色较深,叶片肥厚,始花节位为第8片叶左右,花穗间隔3片叶,高温逆境下坐果能力强。果实粉红色,圆形,单果质量250 g左右。果面光滑,果硬,耐贮运,花蒂小,畸裂果率低,果色艳丽,商品性好。每667 m2产量5 700kg左右。含有抗番茄黄化曲叶病毒病的Ty-1、Ty-3a基因和抗灰叶斑病的Sm基因,综合抗性强。适于我国北方各地晚春及夏季保护地种植。     

西瓜新品种—郑果5506的选育

郑果5506是以具有后绿标记性状的自选单系96B90为母本、正常绿自选单系96B72为父本杂交育成的西瓜新品种,苗期能鉴定出杂交种子纯度,最早鉴定时间为播种后7～10d。该品种平均666.7m2产量4090.5kg,比对照增产16.5%。全生育期100d,果实发育期32d,单瓜质量5kg左右,最大可达10kg。果实椭圆形、皮色墨绿、果肉红色、中心可溶性固形物含量为11.0%左右。果皮硬,耐贮运,较抗病毒病(ZYMV)。