桃种质资源亲缘关系的研究进展

种质资源是现代育种和生物技术研究的物质基础。桃种质资源亲缘关系的研究将为探讨桃的起源、进化、分类、育种和资源利用提供科学依据。本文从形态学、细胞学、孢粉学、生物化学及DNA分子标记等几个方面综述了桃种质资源亲缘关系的研究进展,探讨了桃种质资源亲缘关系的研究现状、前景及尚需解决的问题,并就进一步开展桃种质资源亲缘关系的研究进行了分析,提出桃种质野生种、近缘野生种厦不同栽培品种群间的分子系统学关系是今后研究的重点。     

作物种质资源表型性状鉴定评价:现状与趋势

表型是作物基因型与环境互作后呈现出来的性状,包括形态学、生育期、产量、品质、抗性等性状。作物种质资源具有丰富的遗传多样性,并经过数千年在世界不同区域驯化利用中的人工选择,形成了表型性状的多样性,构成育种家选育作物新品种的物质基础。认识和发现作物种质资源表型的多样性需要通过系统、科学的鉴定,特别是培育适应全球气候变化下环境的品种,更需在大量种质资源中发掘和利用抗旱、耐热、抗病虫、水肥高效利用等特性的材料。作物种质资源各类表型性状的鉴定需要对环境进行有效的控制,而多年多点的鉴定可以准确观察鉴定性状的变异水平或表达稳定性,是育种家准确选择和利用性状的重要依据。作物种质资源表型性状的鉴定主要采用田间鉴定、设施鉴定、仪器分析、感官鉴定的方式。近年来,作物种质资源表型性状鉴定已从单一环境、低通量、粗放型鉴定转变为多年多环境、重点性状、高通量精准型鉴定。随着组学技术、智能与信息技术的快速发展,作物种质资源的表型性状鉴定已进入一个新阶段,形成作物育种中重要性状准确快速发掘与应用的坚实基础。     

台湾早熟蜜桃优良芽变新种质'五月红'的鉴定

桃是我国重要的果树种类,分布十分广泛,在水果生产中排第四位,但适合南方栽培的品种却稀少。该研究通过资源调查在广西大学标本园内的一棵台湾早熟蜜桃大枝上发现一个芽变新种质,命名为‘五月红'',并进一步对其主要生物学特性、植物学性状以及果实经济性状等进行观测分析,同时还通过SRAP分子标记检测与母株台湾早熟蜜桃的差异性。结果表明:‘五月红''芽变新种质成熟期比台湾早熟蜜桃提前20 d左右,5月上中旬成熟,果变大,核变小,可食率提高,且颜色均匀,可溶性固形物含量显著提高,保持了台湾早熟蜜桃需冷量低、品质优良和风味极佳的优点,属于特早熟优质种质资源; 通过琼脂糖电泳检测SRAP扩增组合引物me9/em5在‘五月红''DNA样品中能够扩增到1 200 bp大小的特异性条带,表明‘五月红''在DNA遗传水平上与母株台湾早熟蜜桃发生了变异,属于新的特早熟种质资源。‘五月红''芽变新种质的发现将为选育适合南方栽培的特早熟桃品种提供重要材料,有助于优化不同熟期品种的栽培结构,进而促进南方桃种植产业经济效益的提高。     

广东省果梅种质资源主要性状的鉴定评价

阐述了广东省果梅种质资源的果实主要性状、生物学特性和植物学特征(主要包括栽培类型、果形、果重、肉质、果实可食率、果实内含物、果核核尖尖度、果实成熟期、花、树型和抗病性等),结果表明:(1)广东果梅种质资源变异广泛,蕴含有大量可供生产利用的优良种质;(2)栽培上有白梅、青梅、红梅和黄梅4类;(3)成熟期4月上旬至5月上旬,为我国最早熟的品种群。并介绍了优良品种的选育和推广利用情况。     

45 份木豆种质资源物候期及形态多样性分析

对收集的45 份木豆(Cajanus cajan)种质资源进行物候期和形态性状指标的观测, 并以此为基础进行各指标的变异系数、相关性分析和聚类分析, 分析木豆种质资源的遗传多样性, 筛选优异种质资源。结果表明: 木豆种质资源形态性状多样性丰富, 45 份种质资源的8 个数量遗传性状变异系数为3.73%-17.84%, 花轴长度与中央小叶宽、中央小叶叶长、旗瓣大小相关性显著(P<0.05)。基于8 个形态指标的聚类分析将45 份种质划分为三大类群, 各类群间形态性状差异明显, 群体表现跟地域来源间没有直接关系, 第一、第二类群可以进一步考察作为育种材料。     

我国冬瓜、节瓜种质资源研究现状及建议

冬瓜及其变种节瓜原产我国南部地区,是我国传统的重要菜药兼用型蔬菜品种,现广泛分布于亚洲的热带、亚热带和温带地区。目前我国国家种质资源库中保存的冬瓜和节瓜种质资源分别只有299份和69份,且仅对几个种质特征进行了简单描述,许多重要的种质特征信息尚为空白,种质资源的遗传多样性也众说不一。建议今后我国冬瓜和节瓜种质资源研究应重点开展以下几个内容:(1)搜集与抢救散落在民间的大量冬瓜、节瓜种质资源,扩充国家种质资源库;(2)系统、完整地对冬瓜、节瓜种质资源的特征特性进行鉴定;(3)创建我国冬瓜、节瓜种质资源的分子身份证产权保护系统;(4)鉴别和区分冬瓜种质资源中的同名异物或同物异名资源,构建核心冬瓜、节瓜种质资源库。     

杜仲种质资源果实主要数量性状变异及概率分级

为更好对杜仲种质资源果实进行评价及描述,丰富数量化、规范化的杜仲种质资源描述系统。本研究以331份杜仲种质资源为材料,对杜仲果实18个主要数量性状进行统计分析和概率分级。结果显示：杜仲果实数量性状变异较为丰富,硬脂酸变异系数最大,为17.88%,其次是种仁大小指数（17.17%）,亚麻酸变异系数最小,为4.64%。经K-S检验,除种仁横径和种仁大小指数Sig值小于0.05外,其余性状均大于0.05,符合正态分布。种仁横径和种仁大小指数呈偏态分布,去除拖尾部分,也近似看作正态分布。对符合正态分布的数量性状统一用（X-1.2818S）、（X-0.5246S）、（X+0.5246S）、（X+1.2818S）4个点分为5级,使1~5级出现的概率分别为10%、20%、40%、20%和10%。本研究初步建立了杜仲种质资源果实数量性状概率分级指标体系,对杜仲种质资源果实性状评价、利用及良种选育具有一定指导意义,同时为我国杜仲种质资源果实性状描述规范和数据标准化的建立提供参考。     

作物种质资源品质性状鉴定评价现状与展望

作物种质资源品质性状鉴定评价是作物种质资源研究的重要方面,是深入挖掘、广泛利用作物种质资源的基础。本文对近年来作物种质资源品质性状鉴定评价情况进行了回顾,总结了鉴定评价工作取得的主要进展:完成了近20万份的作物种质资源(约占保存总数的50%)主要营养品质性状的初步鉴定评价;作物种质资源品质鉴定评价内容涉及面广、鉴定的品质性状变异性大、多样性丰富;提高了作物种质资源品质性状鉴定评价标准化程度。此外还介绍了国际上有关品质性状鉴定的发展趋势,并对未来国内作物种质资源品质性状鉴定评价提出了意见和建议。     

大麦表型多样性分析及优异饲草种质资源筛选

为探究中国库存大麦种质资源的表型多样性及其变异规律,同时挑选高生物产量的大麦遗传资源发展饲草大麦,本研究以来源于全国不同地区的102份库存高秆大麦种质为材料,通过Shannon-Weaver多样性指数、相关分析、聚类分析、主成分分析等方法对15个表型性状进行综合评价。结果表明:15个性状中拔节期底部叶片黄化、倒伏性、灌浆期底部叶片黄化、千粒重变异较大,粒宽、株高变异较小,表型多样性指数范围为0.729～0.957,皮裸性、千粒重、籽粒周长、灌浆期株高等性状的遗传多样性较高。不同来源种质间表型多样性比较结果表明,冬大麦生态区表型多样性(0.721)高于西南及青藏高原裸大麦生态区(0.706)。相关分析、主成分分析、聚类分析均表明,皮裸性是影响大麦种质表型差异的重要影响因素,而倒伏、拔节期和灌浆期底部叶片黄化等饲草相关性状相对独立。聚类分析将102份种质分为4类,相同来源地的种质聚在一起。本研究结果表明中国库存大麦种质资源具有丰富的表型多样性,从中筛选的高秆、大叶、抗倒伏等优异性状的大麦资源,为后续培育青饲、青贮专用型大麦品种提供了资源保障。     

桃花器和开花特性研究

对国家果树种质资源南京桃圃保存的507份桃种质资源进行了花期、花型、花径、雌蕊高度(与雄蕊比)、花粉育性的调查,结果表明,需冷量少的品种花期早于其他大部分种质资源,始花期以及花期持续的时间与当年的气候和花期天气尤其是温度有关.84.4%的种质资源具蔷薇形花,78.5%的铃形花种质资源为黄桃;66.1%的种质资源花径在3.7～4.7cm,花径最大的是观赏鲜食兼用的重瓣花种质资源花玉露;90. 5%的种质资源雌蕊高于或近等于雄蕊,蟠桃88.2%的种质资源雌蕊低于雄蕊;花粉可育种质资源443份,占种质资源总数的87.4%.     

Seasonal patterns of reproductive and vegetative sink activity in early and late maturing peach (Prunus persica) cultivars

Weekly measurements of fruit growth, fruit respiration and shoot extension growth were made in the field on early (June Lady) and late (O'Henry) maturing cultivars of peach ( Prunus persica L. Batsch). The seasonal patterns of fruit growth and respiration for the two cultivars were very similar except that the early maturing cultivar bloomed a few days earlier than the late cultivar and had a shorter intermediate stage (Stage II) of fruit growth. Maximum rates of fruit respiration per unit weight at 20°C were similar for both cultivars during the first two stages of fruit growth but higher for the early cultivar during the final stage of fruit growth. Maximum fruit growth rates within any particular stage of fruit growth were similar for both cultivars, but the mean fruit weight of the late cultivar was greater at the end of Stage II, because of the extended length of this stage compared to the early cultivar. The final stage of most rapid fruit growth and respiration coincided with the period of most rapid shoot extension growth in the early maturing cultivar but occurred after this period in the late maturing cultivar. Genetic selection for early fruit maturity in peach has apparently had little effect on timing of shoot growth and this may result in increased competition between vegetative and reproductive sinks during peak periods of fruit growth in early maturing cultivars.     

Effects of orchard host plants (apple and peach) on development of oriental fruit moth (Lepidoptera: Tortricidae)

Studies were designed to examine the effects of host plants (apple, Malus domestica Borkh., and peach, Prunus persica L.) on the development of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae). Oriental fruit moth larvae developed faster on peach than on apple, both on fruit as well as on growing terminal shoots. On fruit, these differences were shown to cause significant changes in both the rate (approximately 20-60 degree-days earlier emergence on peach than on apple) and patterns of adult emergence among several cultivars of peaches and apples. Slopes of female emergence plots varied by host in 2003, with emergence occurring over a longer period on peach cultivars than on apple cultivars (with one exception). Slopes of male emergence curves did not differ by cultivar in 2003. These host-driven effects could impact the efficacy of traditional pest management approaches and probably complicate efforts to predictively model G. molesta populations in mixed cultivar orchards. Such developmental effects may help to explain previously observed differences in patterns of pheromone trap captures in peach versus apple orchards. Host-associated effects should be incorporated into future models to develop more realistic predictive tools and thus improve integrated pest management efforts.     

Maximum Vegetative Growth Potential and Seasonal Patterns of Resource Dynamics during Peach Growth

The maximum vegetative growth potential of two peach [Prunuspersica (L.) Batsch] cultivars that differ in the timing ofresource demand for reproductive growth was determined in termsof stem extension, stem and leaf dry weight accumulation, andtrunk radial increment on defruited trees. The maximum vegetativegrowth potentials were similar on the two cultivars indicatingthat the greater partitioning of dry weight to vegetative growthfrequently observed on early maturing cultivars compared tolate maturing cultivars is the result of a shorter period ofcompetition between reproductive and vegetative growth, ratherthan a genetic difference in vegetative growth potential. Onboth cultivars, stem extension and leaf dry weight accumulationceased in mid-summer, however stem dry weight accumulation andtrunk radial increment increase continued through the autumn. The presence of fruit did not have a detectable effect on thefinal stem length, stem dry weight or leaf dry weight on theearly maturing cultivar, but it reduced final stem length anddry weight by 43 and 56%, respectively on the late maturingcultivar. The presence of fruit did decrease stem length, stemdry weight and leaf dry weight on the early maturing cultivarfor 1 month prior to and 1 month after fruit harvest. Fruitdecreased final trunk radial increment by 42 and 77% on theearly and late maturing cultivars, respectively. These reductionsin vegetative growth indicate that resource partitioning tovegetative growth was reduced by competition with fruit growth. Comparison of stem relative extension rates and stem and leafrelative growth rates on fruited and defruited trees indicatedthat vegetative growth was resource-limited shortly after vegetativebud break on fruited trees of both cultivars. This period ofresource-limited vegetative growth corresponded to a periodof resource-limited fruit growth identified in an earlier study.During the period of resource-limited vegetative growth, assimilatesupply was low due to low leaf area index, and carbohydratedemand was relatively high due to high vegetative and reproductivegrowth potentials, creating resource-limited growth conditions.Copyright1995, 1999 Academic Press Maximum vegetative growth potential, carbon economy, partitioning, resource availability, resource limitation, source-limited growth, growth analysis, relative growth rate, peach, Prunus persica (L.) Batsch     

Isolation and characterization of six peach cDNAs encoding key proteins in organic acid metabolism and solute accumulation: involvement in regulating peach fruit acidity

As in many other fleshy fruits, the predominant organic acids in ripe peach ( Prunus persica (L.) Batsch) fruit are malic and citric acids. The accumulation of these metabolites in fruit flesh is regulated during fruit development. Six peach fruit-related genes implicated in organic acid metabolism (mitochondrial citrate synthase; cytosolic NAD-dependent malate dehydrogenase, and cytosolic NADP-dependent isocitrate dehydrogenase) and storage (vacuolar proton translocating pumps: one vacuolar H⁺-ATPase, and two vacuolar H⁺-pyrophosphatases) were cloned. Five of these peach genes were homologous to genes isolated from fruit in other fleshy fruit species. Phylogenetic and expression analyses suggested the existence of a particular vacuolar pyrophosphatase highly expressed in fruit. The sixth gene was the first cytosolic NAD-dependent malate dehydrogenase gene isolated from fruit. Gene expression was studied during the fruit development of two peach cultivars, a normal-acid (Fantasia) and a low-acid (Jalousia) cultivar. The overall expression patterns of the organic acid-related genes appeared strikingly similar for the two cultivars. The genes involved in organic acid metabolism showed a stronger expression in ripening fruit than during the earlier phases of development, but their expression patterns were not necessarily correlated with the changes in organic acid contents. The tonoplast proton pumps showed a biphasic expression pattern more consistent with the patterns of organic acid accumulation, and the tonoplast pyrophosphatases were more highly expressed in the fruit of the low-acid cultivar during the second rapid growth phase of the fruit.     

桃果肉花色苷遗传多样性及红肉桃判定指标的探讨

运用比色法(UV)和高效液相色谱法(HPLC)测定68份桃品种果肉花色苷含量,比较2种测定结果的一致性,分析桃果肉花色苷的遗传多样性,初步提出红肉桃的判定标准。结果表明,2种方法测定白肉品种花色苷含量接近,可根据实际情况进行选择分析方法,而黄肉品种应尽可能选用高效液相色谱法(HPLC)。HPLC定性定量检测结果表明,48份材料检测出矢车菊-3-葡萄糖苷,是桃果肉中主要的花色苷种类,乌黑鸡肉桃,大果黑桃果肉中同时检测到矢车菊-3-芸香糖苷。根据高效液相色谱法测得花色苷含量将桃划分为5个等级,含量20 mg/100 g定为红肉桃的划分临界点。本研究中共鉴定出5份红肉桃品种,感官判定且风味为甜的红肉桃不符合上述判定标准,需要进一步研究完善。     

Maximum Fruit Growth Potential and Seasonal Patterns of Resource Dynamics During Peach Growth

Maximum fruit growth potential, the growth attained by fruitswhen they are grown under optimal environmental conditions inthe presence of a non-limiting supply of resources, was estimatedfor two peach [Prunus persica (L.) Batsch] cultivars that differin the timing of resource demand for reproductive growth. Maximumpotential fruit growth was estimated on trees that were heavilythinned at bloom. On these trees, resource availability exceededresource demand for fruit growth. For both cultivars, the mean dry weights of fruits grown onunthinned trees were approximately half the mean dry weightsof fruits grown on trees that were heavily thinned at bloom,indicating that fruit growth was source-limited on unthinnedtrees. Comparison of the seasonal patterns of relative growthrate of fruits on unthinned and heavily thinned trees indicatedthe source-limited fruit growth occurred during distinct periodsof the growing season. On the early maturing cultivar, source-limitedfruit growth occurred from 300 degree-days after bloom untilharvest (4·5-10 weeks after bloom). On the late maturingcultivar, source-limited fruit growth occurred from 200-900and 1600-1900 degree-days (3·5-12 and 18-20 weeks) afterbloom. Although the final dry weight of fruits on the early maturingcultivar was only half that of fruits on the late maturing cultivar,the potential net sink strength of fruits was significantlyhigher on the early than the late maturing cultivar throughoutthe entire growth period of the early maturing cultivar. Resourceavailability for fruit growth was similar on the early and latematuring cultivars, indicating that selection for early maturingfruits has not changed the patterns of resource availabilityfor fruit growth.Copyright 1995, 1999 Academic Press Maximum fruit growth potential, carbon economy, partitioning, resource availability, resource limitation, source-limited growth, sink activity, sink strength, growth analysis, relative growth rate, Prunus persica (L.) Batsch, peach     

The involvement of 1-aminocyclopropane-1-carboxylic acid synthase isogene, Pp-ACS1, in peach fruit softening

Ethylene promotes fruit ripening, including softening. The fruit of melting-flesh peach (Prunus persica (L). Batsch) cultivar 'Akatsuki' produces increasing levels of ethylene, and the flesh firmness softens rapidly during the ripening stage. On the other hand, the fruit of stony hard peach cultivars 'Yumyeong', 'Odoroki', and 'Manami' does not soften and produces little ethylene during fruit ripening and storage. To clarify the mechanism of suppression of ethylene production in stony hard peaches, the expression patterns of four ethylene biosynthesis enzymes were examined: ACC synthases (Pp-ACS1, Pp-ACS2, and Pp-ACS3) and ACC oxidase (Pp-ACO1). In the melting-flesh cultivar 'Akatsuki', Pp-ACS1 mRNA was dramatically induced after harvesting, and a large amount of ethylene was produced. On the other hand, in stony hard peaches, Pp-ACS1 mRNA was not induced during the ripening stage, and ethylene production was inhibited. Since Pp-ACS1 mRNA was induced normally in senescing flowers, wounded leaves, and wounded immature fruit of 'Yumyeong', Pp-ACS1 was suppressed only at the ripening stage, and was not a defect in Pp-ACS1. These results indicate that the suppression of fruit softening in stony hard peach cultivars was caused by a low level of ethylene production, which depends on the suppressed expression of Pp-ACS1.     

Partitioning of (13)C-photosynthate from spur leaves during fruit growth of three Japanese pear (Pyrus pyrifolia) cultivars differing in maturation date

BACKGROUND AND AIMS: In fruit crops, fruit size at harvest is an important aspect of quality. With Japanese pears (Pyrus pyrifolia), later maturing cultivars usually have larger fruits than earlier maturing cultivars. It is considered that the supply of photosynthate during fruit development is a critical determinant of size. To assess the interaction of assimilate supply and early/late maturity of cultivars and its effect on final fruit size, the pattern of carbon assimilate partitioning from spur leaves (source) to fruit and other organs (sinks) during fruit growth was investigated using three genotypes differing in maturation date. METHODS: Partitioning of photosynthate from spur leaves during fruit growth was investigated by exposure of spurs to (13)CO(2) and measurement of the change in (13)C abundance in dry matter with time. Leaf number and leaf area per spur, fresh fruit weight, cell number and cell size of the mesocarp were measured and used to model the development of the spur leaf and fruit. KEY RESULTS: Compared with the earlier-maturing cultivars 'Shinsui' and 'Kousui', the larger-fruited, later-maturing cultivar 'Shinsetsu' had a greater total leaf area per spur, greater source strength (source weight x source specific activity), with more (13)C assimilated per spur and allocated to fruit, smaller loss of (13)C in respiration and export over the season, and longer duration of cell division and enlargement. Histology shows that cultivar differences in final fruit size were mainly attributable to the number of cells in the mesocarp. CONCLUSIONS: Assimilate availability during the period of cell division was crucial for early fruit growth and closely correlated with final fruit size. Early fruit growth of the earlier-maturing cultivars, but not the later-maturing ones, was severely restrained by assimilate supply rather than by sink limitation.     

Phenology and infestation patterns of plum curculio (Coleoptera: Curculionidae) on four highbush blueberry cultivars

The plum curculio, Conotrachelus nenuphar (Herbst), is a well known pest in apple and peach orchards, but it also is capable of having an economic impact in highbush blueberries. Host phenology and plum curculio oviposition patterns were determined on four highbush blueberry cultivars differing in fruit maturation period. Numbers of oviposition scars were higher on early- ('Weymouth') and mid-season ('Duke' and 'Bluecrop') blueberries than on late-season 'Elliott' in 2001, 2002, and 2003. In 2002, eggs were first present on the three earliest cultivars 21 d before those on 'Elliott', whereas eggs were found on 'Elliott' >40 d after the last sample with eggs for the other three cultivars. The pattern of host phenology and infestation levels suggested that plum curculio oviposition synchronizes well with the availability of suitable fruit for oviposition on early and mid-season cultivars compared with a late-season cultivar of highbush blueberries. The implications of a transition to use of reduced-risk insecticides are discussed in relation to plum curculio management.