不同砧穗组合对红肉蜜柚树体和果实品质的影响

为研究张家界地区不同砧木类型对红肉蜜柚树体和果实品质的影响,以2 种砧木和4 种中间砧类型的红肉蜜柚为试材,对植株生长势、果实内在和外在品质进行测定和比较。结果表明,不同砧穗组合红肉蜜柚植株生长势表现出较大差异,其中酸柚砧和菊花芯柚中间砧组合株高最高,温州蜜柑中间砧组合株高最低;酸柚砧亲和性较好,枳砧亲和性较差,存在明显“大脚”现象;椪柑中间砧的接穗粗度明显大于中间砧,其他组合均略小。不同砧穗组合对红肉蜜柚果实品质有明显影响。外在品质方面,酸柚砧和椪柑、菊花芯柚中间砧组合果实体积明显大,单果重也明显高;果实中心柱大小与果实大小有较高相关性;砧穗组合类型对果形指数影响不大。内在品质方面,椪柑中间砧组合果实可溶性固形物含量明显 低,而酸柚砧和菊花芯柚中间砧组合果实可滴定酸含量明显高于其他组合。以酸柚为砧木,树势旺盛、果实体积大、单果重更高,虽然可滴定酸稍高,但是可溶性固形物含量也不低,同时不存在与接穗品种不亲和的现象,所以酸柚的综合表现比较均衡,是目前比较适合用作红肉蜜柚砧木的类型。本研究为张家界地区发展红肉蜜柚产业,提高产量、改善品质提供了参考。     

AM真菌种间差异对枳壳苗营养生长及矿质含量的影响

【研究目的】利用AM真菌进行柑桔菌根化育苗是培育壮苗和提高果品品质的新趋势，在对枳壳菌根苗进行研究的基础上，找到一个较好的优势菌种作为育苗菌剂。【方法】盆栽条件下研究了AM真菌Gigaspora margarita、Glomus mosseae和Glomus versiforme对枳壳实生苗营养生长及矿质含量的影响，并比较了种间差异的效应。【结果】接种AM真菌的枳壳幼苗根系均有效地被侵染，与对照相比，能显著促进植株根系和茎叶的生长，对须根的生长促进作用尤为突出；提高了叶片矿质元素N、P、K、Ca、Mg、Zn、Cu和Mn的含量，与对照差异均达到显著水平。3种AM真菌种间比较，其效应排序为Glomus mosseae＞Gigaspora margarita＞Glomus versiforme，但叶片矿质元素的含量与生长趋势并不完全一致。【结论】接种Glomus mosseae处理生长最好，矿质元素N、P、Mg和Cu的含量最高，菌根依赖性最大，且差异显著。AM真菌G.mosseae是参试3个菌种中培养枳壳菌根化壮苗的最佳菌种。     

三种柑橘砧木幼苗抗冻性比较

陕南柑橘在近年来持续受到周期性大面积冻害,本研究对不同柑橘砧木幼苗抗冻性进行比较,为陕南地区抗冻柑橘砧木品种的选择提供理论参考。以‘枳壳’、‘大叶香橙’、‘香橼’3种柑橘砧木幼苗为试材,研究-7℃冷冻胁迫对柑橘砧木幼苗形态和相关生理指标的影响,并采用隶属函数法比较3种柑橘砧木的抗冻能力。结果显示:-7℃冷冻处理36 h后,3种柑橘砧木幼苗均出现不同程度的失水萎焉,与对照组相比,植株鲜重和干重、叶片鲜重和干重均显著降低。叶片的相对电导率显著升高,丙二醛和超氧阴离子含量均呈不同程度的升高,其中‘大叶香橙’增加最高,分别为1.28倍和1.59倍。另外,与对照组相比,渗透调节物质脯氨酸和可溶性糖含量均呈升高趋势,但脯氨酸含量均无显著性差异,‘枳壳’和‘香橼’叶片中可溶性糖含量均明显升高。隶属函数综合分析结果显示‘枳壳’抗冻能力最强,‘香橼’次之,‘大叶香橙’最弱。-7℃冷冻胁迫对柑橘砧木幼苗形态和生理指标均有明显的影响,根据综合分析结果,柑橘砧木‘枳壳’和‘香橼’品种可在陕南地区实践栽培中大力推广。     

Analysis of genetic variability in various tissue culture-derived lemon plant populations using RAPD and flow cytometry

Five populations of lemon plants [Citrus limon (L.) Burm] obtained from undeveloped ovules through different tissue culture procedures were examined for the presence of somaclonal and irradiation-induced genetic variation. Tested groups were: (1) nucellar seedlings; (2) organogenic, regenerated via adventitious buds from nucellar seedling internodes; (3) embryogenic population, regenerated from non-irradiated nucellar callus via somatic embryogenesis; (4) embryogenic population, regenerated from irradiated nucellar callus via somatic embryogenesis; and (5) protoplast-derived, regenerated via somatic embryogenesis. Genomic DNA samples from 360 plants (72 from each group) were screened for polymorphism among RAPD fingerprints amplified by 10 decamer primers. Among all tested plants, genetic variation was detected only within the group of plants recovered from irradiated embryogenic calli. Out of 72 plants from that group, three had RAPD fingerprints different from the rest of the population, and fourth plant was found to be cytochimeric, consisting of diploid and tetraploid cells as revealed by flow cytometry. In all other populations of regenerated plants, we did not come across any plants with changed ploidy level.     

Sex chromosomes and quantitative sex expression in monoecious hemp (Cannabis sativa L.)

Hemp (Cannabis sativa) has a highly variable sexual phenotype. In dioecious hemp, the sex is controlled by heteromorphic sex chromosomes according to an X-to-autosomes equilibrium. However, in monoecious hemp, the sex determinism remains widely unknown and has never been related to a quantitative approach of sex expression. The present paper aims to contribute to the comprehension of the sex determinism in monoecious hemp by assessing the genotypic variability of its sex expression and establishing its sex chromosomes. Five monoecious and one dioecious cultivars were grown in controlled conditions under several photoperiods. The monoecy degree of 194 monoecious plants was recorded at each node by a figure ranging from 0 (male flowers only) to 6 (female flowers only). The genome size of 55 plants was determined by flow cytometry. The DNA of 115 monoecious plants was screened with the male-associated marker MADC2. The monoecy degree varied significantly among monoecious cultivars from 3.36 ± 2.28 in ‘Uso 31’ to 5.70 ± 0.81 in the most feminised ‘Epsilon 68’. The variation of monoecy degree among cultivars remained consistent across trials despite a significant “cultivar × trial” interaction and partly agreed with their earliness. The genome size of monoecious plants (1.791 ± 0.017 pg) was not different from that of females (1.789 ± 0.019 pg) but significantly lower than that of males (1.835 ± 0.019 pg). MADC2 was absent from all monoecious plants. These results strongly support that cultivars of monoecious hemp have the XX constitution and that their sex expression has a genetic basis.     

柑橘地方优良品种‘贡柑’起源的初步研究

利用随机扩增多态性DNA(RAPD)技术,研究了地方优良品种‘贡柑’与部分柑橘属植物之间的亲缘关系,10条引物共扩增出87条谱带,多态性谱带率为97.7％,通过各供试材料间遗传相似系数建立的聚类树状图,能准确地区分各种、品种、品系的关系,此外对‘贡柑’的起源进行了初步的探讨,支持‘贡柑’是由本地橘和橙的自然杂交而来的观...     

Generation and characterisation of colchicine-induced autotetraploid Lavandula angustifolia

Lavandula angustifolia (lavender) is a small woody perennial grown for essential oil, which is steam distilled from flowers. To potentially improve size of flowers and oil yield we produced and characterised autotetraploid plants. L. angustifolia seed germinated in the presence of the mitotic spindle inhibitor colchicine at concentrations of 125 mg l⁻¹ or less resulted in plants carrying sports with larger flowers. Propagation of two sports gave rise to putative polyploid cultivars C3/2 and C6/24. Direct chromosome counts in root tip cells of seedlings from four common cultivars of L. angustifolia and the seed lot from which C3/2 and C6/24 were derived was 50 whereas C3/2 and C6/24 had greater than 90 chromosomes indicating they were autotetraploid. Ploidy level assessed by flow cytometry (FCM) of nuclei showed that 12 cultivars of L. angustifolia had similar nuclear DNA content whereas C3/2 and C6/24 had double the amount of DNA confirming autotetraploidy. The genome size (1C-value) of a diploid L. angustifolia cultivar was estimated by FCM to be 0.90 (±0.07) pg. Morphological characteristics were measured in autotetraploid and control plants. Autotetraploids had thicker peduncles, larger flowers and larger seeds than diploids. Scanning electron microscopy revealed peltate glandular trichomes were larger in the tetraploids relative to diploids. Both tetraploid and diploid cultivars had complex non-glandular trichomes on leaves and sepals and two different types of capitate glandular trichomes were identified on leaves. Autotetraploid lavenders represent useful germplasm both for commercial oil production and future breeding.     

Heterogeneity of random amplified polymorphic DNA sequences in individual seedlings and bulked samples of four cultivars of Brassica napus

Using four different random amplified polymorphic DNA (RAPD) primers, a qualitative and quantitative assessment was made of the level of DNA sequence heterogeneity present in the seedlings of four representative Australian rapeseed cultivars. It was found that, depending upon the primer/cultivar combination, the seedlings diverged from total homogeneity to almost complete heterogeneity. The increase or decrease of sample-specific RAPD sequences was evaluated in proportional mixtures of DNA from individual seedlings. These results were then compared with those obtained from bulked DNA samples containing DNA from all the seedlings of a cultivar. From these comparisons, it was found that for a specific RAPD to be detectable in a bulked sample, the particular polymorphism had to be present in at least 15% of the individual seedlings. Even so, the bulked samples produced cultivar-specific RAPD banding patterns with all four primers, showing that any of these primers could be used to identify the different rapeseed cultivars. In contrast to the cultivars ‘Oscar’, ‘Dunkeld’ and ‘Narendra’, the cultivar ‘Rainbow’ was found to be highly heterogeneous—as shown by a diversity of RAPD combinations rather than the presence of differing length RAPDs—and it is suggested that this heterogeneity may be related to the improved tolerance of this cultivar to blackleg infection.     

南丰蜜橘胚性愈伤组织诱导及其转化研究

摘要∶南丰蜜橘是原产于中国的古老柑橘品种,其果实皮薄而肉甜,深受消费者喜爱,当前南丰蜜橘的品质发生劣变,影响了其商品价值。为采用基因工程育种以改善南丰蜜橘品质,通过诱导其愈伤组织并以其为试材进行了转基因研究。南丰蜜橘自种子实生苗下胚轴处长产生出愈伤组织,挑选胚性愈伤组织进行增殖后,采用根癌农杆菌介导法进行开花相关基因AP1的转化。结果获得22团抗性愈伤组织,平均产出率为7.3团/皿,表明该品种有较高的转化率。抗性愈伤组织经PCR分析、Southern blot检测证实为转化子。本研究结果表明南丰蜜橘胚性愈伤组织是基因工程改良的良好受体,可用于其它基因的转化研究。     

Inheritance of resistance to plum pox potyvirus (PPV) in 'Stella' apricot seedlings

Resistance to sharka (plum pox potyvirus) was studied in 74 seedlings resulting from open pollination of the resistant apricot cultivar ‘Stella’. Each seedling was inoculated at the base by a chip-bud from a diseased GF305 peach tree. To follow tlie spread of virus into the scedlings. a Chip-bud of a healthy GF305 and another from a healthy sensitive Manicot apricot were grafted above the inoculation point in the order described. Six observations of symptoms were made in the leaves of the GF305 used For inoculation, the GF305-control, the Manicot-control and the ‘Stella’ seedlings during four growth cycles. An enzyme-linked immunosorbent assay (ELISA) was applied to the leaves of the ‘Stella’ seedlings. No ‘Stella’ seedling showed symptoms of sharka. Only three seedlings reacted positively to the ELISA. Substantial differences were observed in the speed of virus propagation through the ‘Stella’ seedlings, some of them showing a strong resistance to virus translocation. The possible use of the ‘Stella’ cultivar in apricot breeding programmes to obtain resistant cultivars is discussed.     

Production of two mandarin × trifoliate orange hybrid populations via embryo rescue with verification by SSR analysis

Intergeneric sexual hybridizations were conducted between two genera of Rutaceae, with Satsuma mandarin (Citrus unshiu Marc) and Red tangerine (C. reticulata Blanco) as maternal parents, and Poncirus trifoliata (L.) Raf as the paternal parent, in an effort to generate hybrid populations for both molecular mapping and rootstock breeding. Embryo rescue is important for citrus sexual breeding because polyembryony can interfere with hybrid embryo recovery. Immature embryos of 80, 85, 90 days after pollination (DAP) from the Satsuma mandarin (S) × trifoliate orange (P) cross, 80 and 85 DAP from the Red tangerine (R) × trifoliate orange (P) cross, were cultured on MG1.0 medium consisting of MT basal medium supplemented with 1.0 mg l⁻¹ GA₃ and 4% sucrose. The results showed that 80 DAP was the optimal time for embryo rescue of the tested crosses, as evidenced by embryos at this stage exhibiting high germination rates, 37.3% for S × P and 51.3% for R × P. Among the eight tested media, MT medium supplemented with 0.5 mg l⁻¹ GA₃ was the best one for Satsuma mandarin, and MT plus 1.0 mg l⁻¹ GA₃ for Red tangerine. A total of 85 plants were obtained from S × P, and 340 from R × P. Out of them, 44 progenies from S × P and 111 from R × P were sufficiently confirmed to be hybrids by morphological characterization and SSR analysis. In addition, two hybrid callus lines were obtained from S × P and R × P respectively.     

应用流式细胞术测定药用植物黄芩基因组大小

为了探讨和优化应用流式细胞术(FCM)测定药用植物的基因组大小（或称C值）的方法,本文分别以新鲜、幼嫩和硅胶干燥的叶片为材料,采用Otto和LB01两种细胞核提取液,利用流式细胞术对黄芩C值进行测定。结果表明,选用豌豆为内标植物时,相比LB01一步法,Otto两步法在低温提取、离心和保存条件下,碘化丙啶染色浓度为0.02 mg/mL,得到的细胞核散点图相对集中,碎片较少,容易准确取门,CV较小。不同提取材料表明,幼嫩叶片和新鲜叶片利用Otto二步法均能到高质量的细胞核悬液,细胞核数量多且散点图集中,有利于取门和测定的C值更准确。而干燥叶片提取的细胞核得到的散点图分散,无法准确取门和测定C值。最终,以黄芩为例系统地优化了利用流式细胞术测定药用植物基因组大小的方法,并首次成功测定黄芩1C值为0.58 pg,基因组大小约为562 Mbp,从而为了解物种的遗传背景和基因组值在系统演化中的变化规律,以及黄芩属药用植物资源的遗传评价和保护利用等方面的研究提供理论基础。     

Genes for wheat stem rust resistance postulated in German cultivars and their efficacy in seedling and adult‐plant field tests

Stem rust of wheat (caused by Puccinia graminis f.sp. tritici) gained high international attention in the last two decades, but does not occur regularly in Germany. Motivated by a regional epidemic in 2013, we analysed 15 spring and 82 winter wheat cultivars registered in Germany for their resistance to stem rust at the seedling stage and tested 79 of these winter wheat cultivars at the adult‐plant stage. A total of five seedling stem rust resistance genes were postulated: Sr38 occurred most frequently (n = 29), followed by Sr31 (n = 11) and Sr24 (n = 8). Sr7a and Sr8a occurred only in two spring wheat genotypes each. Four cultivars had effective seedling resistance to all races evaluated that could only be explained by postulating additional resistance genes (‘Hyland’, ‘Pilgrim PZO’, ‘Tybalt’) or unidentified gene(s) (‘Memory’). The three winter wheat cultivars (‘Hyland’ ‘Memory’ and ‘Pilgrim PZO’) were also highly resistant at the adult‐plant stage; ‘Tybalt’ was not tested. Resistance genes Sr24 and Sr31 highly protected winter wheat cultivars from stem rust at the adult‐plant stage in the field. Disease responses of cultivars carrying Sr38 varied. Mean field stem rust severity of cultivars without postulated seedling resistance genes ranged from 2.71% to 41.51%, nine of which were significantly less diseased than the most susceptible cultivar. This suggests adult‐plant resistance to stem rust may be present in German wheat cultivars.     

Inheritance of resistance to anthracnose (Colletotrichum capsici) at seedling and fruiting stages in chili pepper (Capsicum spp.)

Inheritance of resistance to anthracnose at fruiting and seedling stages was studied in two F₂ populations from a cross between Capsicum annuum cv. ‘Bangchang’ and Capsicum chinense‘PBC932’. The first F₂ was used to study anthracnose resistance at fruiting stage on mature green and ripe red fruit, and the second F₂ was used to study the resistance at both seedling and fruiting stages. Fruit inoculation was performed on detached fruit using a microinjector. Disease severity was assessed on a 0–9 scale at 7 days after inoculation. Seedling inoculation was performed using a drop method on detached leaves of 4‐week‐old seedlings. Disease severity was assessed on a 1–9 scale at 3 days after inoculation. The distribution of the disease scores of green and red fruit, and seedlings in both F₂ populations suggested a single gene model for each trait. Three different recessive genes were responsible for the three resistances from this cross. Linkage analysis suggested that the resistances at green and red fruit were linked (recombination frequency 0.25), and that the seedling resistance was not linked to the fruit resistances.     

低温胁迫下8种柑橘的生理响应与抗寒性评价

本研究比较了8个柑橘品种的抗寒性并对其进行综合评价,以期了解这8种柑橘的抗寒能力差异并筛选评价柑橘抗寒能力差异的关键指标,这不仅为评价柑橘抗寒性提供了重要参考指标,也为柑橘的扩大引种和栽培提供了依据。以8种柑橘离体枝条为材料,分析0℃、-2℃和-4℃时柑橘的形态和生理生化指标的变化,通过隶属函数综合比较8种柑橘的抗寒能力,同时利用主成分分析法筛选评价柑橘抗寒能力差异的关键指标。结果表明:随着处理温度的逐渐降低,8种柑橘叶片均出现了卷曲、失水、冻斑的现象,同时最大光化学效率(F_v/F_m)、叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素、丙二醛(MDA)含量和相对含水量均呈现显著降低趋势,相对电导率(REC)值呈显著升高趋势,脯氨酸(Pro)和可溶性糖含量呈先升高后降低趋势。隶属函数分析表明,8种柑橘的抗寒能力大小依次为‘南丰蜜桔’>‘华农冰糖’>‘朱红桔’>‘日南1号’>‘椪柑’>‘本地早’>‘千山红’>‘温州蜜柑’。主成分分析表明,REC与主成分的相关系数达到了0.931,可以作为今后评价柑橘抗寒性的主要参考指标。     

Detection of quantitative trait loci for leaf rust resistance in wheat––T. timopheevii/T. tauschii introgression lines

Advanced backcross QTL analysis was used to identify QTLs for seedling and adult plant resistance to leaf rust in introgression lines derived from a cross between the spring wheat cultivar ‘Saratovskaya 29’ and a synthetic allopolyploid wheat (T. timopheevii/T. tauschii). F₂ mapping populations involving two backcross selections (‘BC5’ and ‘BC9’ lines) were genotyped with microsatellite markers. Two significant QTL for adult plant resistance were identified in line ‘BC5’: one on chromosome 2B, but originating from chromosome 2G, explained 31% of the trait variance. The other, derived from T. tauschii and mapped to the short arm of chromosome 2D explained 19% of the trait variance. In the second line, one major seedling and adult plant resistance QTL was identified on chromosome 2B. Both QTL co-located to the same marker interval. Such introgression lines, resulting from the reconstruction of common wheat genome, are of interest both as initial material for breeding and improvement of current cultivars, and as a resource for the study of the interaction and transformation of genomes.     

Identification of a single dominant allele for resistance to blackleg in Brassica napus'Surpass 400'

The inheritance of resistance to blackleg (caused by Leptosphaeria maculans) was examined in the F1 and F2 of a cross between highly resistant canola ‘Surpass 400’ and susceptible ‘Westar’ in the field. Blackleg‐infected canola straw was collected from the field and scattered among plants to increase disease development with the aid of natural rainfall. Disease severity on seedlings was assessed as the average number of lesions on leaves 1 and 2, and on adult plants as the percentage necrosis on a cross‐section of stems immediately above the crown. All ‘Westar’ plants were susceptible (S) and all ‘Surpass 400’ and F1 plants were resistant (R) at both growth stages. Disease severity on F2 plants segregated 3 : 1 (R : S) as expected for a single dominant resistance allele in both the seedling and adult plant stages. There was a high proportion (91.1%) of matching reactions (R‐R and S‐S) between seedling and adult plants. ‘Surpass 400’ is the source of a single dominant allele for blackleg resistance in Brassica napus that is expressed strongly in both seedlings and adult plants.     

Citrus breeding,genetics and genomics in Japan

Citrus is one of the most cultivated fruits in the world, and satsuma mandarin (Citrus unshiu Marc.) is a major cultivated citrus in Japan. Many excellent cultivars derived from satsuma mandarin have been released through the improvement of mandarins using a conventional breeding method. The citrus breeding program is a lengthy process owing to the long juvenility, and it is predicted that marker-assisted selection (MAS) will overcome the obstacle and improve the efficiency of conventional breeding methods. To promote citrus molecular breeding in Japan, a genetic mapping was initiated in 1987, and the experimental tools and resources necessary for citrus functional genomics have been developed in relation to the physiological analysis of satsuma mandarin. In this paper, we review the progress of citrus breeding and genome researches in Japan and report the studies on genetic mapping, expression sequence tag cataloguing, and molecular characterization of breeding characteristics, mainly in terms of the metabolism of bio-functional substances as well as factors relating to, for example, fruit quality, disease resistance, polyembryony, and flowering.     

A diallel crossing approach aimed on selection for ripening time and yield in breeding of new strawberry (Fragaria × ananassa Duch.) cultivars

The extension of the ripening season in open field production is of high economic interest for strawberry growers. Therefore, targeted breeding for extreme early or late ripening cultivars with high yield potential is of particular interest. Thirteen strawberry cultivars were crossed in a reciprocal way without selfing, and the 144 resulting F₁ populations were evaluated in a field trial over a period of two consecutive years. The data were analysed using a mixed‐model approach adapted for diallel crossing designs using SAS 9.3. The variability in the crossing approach is mainly based on the general combining ability (GCA) of the cultivars (additive effects). Specific and reciprocal combining abilities (non‐additive effects) appear less important. The highest GCAs for the trait Marketable Yield were found for the cultivars ‘Polka’ and ‘Yamaska’. The trait Earliness is bilateral with significantly low GCAs for early ripening in ‘Clery’ and ‘Daroyal’ and significantly high GCAs for late ripening in ‘Yamaska’ and ‘Florence’. Crosses with these cultivars are likely to deliver populations with both high yield and an extended ripening period.     

盐胁迫对油桃生理生化特性的影响

为分析不同油桃的耐盐特性,为后续的耐盐品种选育研究打下基础,以‘华光’油桃盆栽苗为试材,研究不同程度盐胁迫对植株茎生理指标的影响。试验发现0.4%盐胁迫下各指标与对照组无明显差异,0.8%盐胁迫中后期开始有一定影响,而1.2%盐胁迫初期时相关指标便有极明显差异,表明该盐环境为植株能够承受的极限。在此基础上,以‘中油桃4 号’、‘艳光’、‘华光’、‘千年红’、‘玫瑰红’5 个品种油桃盆栽苗为试验材料,分析了1.2%盐溶液胁迫下的生理指标变化,研究不同品种油桃的耐盐特性。结果表明：不同油桃品种在盐胁迫下的表现差异性很大,黄肉品种‘中油桃4 号’耐盐特性优于‘千年红’;白肉品种‘华光’耐盐性强于‘艳光’,‘玫瑰红’高于‘华光’;白肉品种耐盐特性整体上强于黄肉品种。