Characteristics and thermodynamics analysis ofoxyacetylene flame brazing joint of Cu/Al tubes

以磨盘柿为试材,研究不同液浸处理对冰温贮藏(-0.5～-0.2)℃柿果涩味转变、品质及生理指标的影响。结果表明:在冰温条件下,用2%浓度的NaCl溶液贮藏磨盘柿,可使果实的乙醇含量在贮藏30～45 d内急剧增加,促进可溶性单宁的降低,在贮藏45 d时达到完全脱涩,并可有效延缓果实硬度的下降,具有脱涩和保脆的双重作用,同时可保持相对较高的可溶性固形物和可滴定酸含量,抑制贮藏后期果实丙二醛和膜相对电导率的增加,减缓果实的衰老进程。     

Fruit antioxidant capacity and self-incompatibility genotype of Ukrainian sweet cherry (Prunus avium L.) cultivars highlight their breeding prospects

Breeding for higher levels of health-promoting components are among the priorities for many fruit crops. Such an approach requires breeding material displaying great variations in the trait to be improved. Commercial sweet cherry cultivars demonstrate only limited variability in fruit antioxidant parameters and hence this study was carried out to characterize some Ukrainian sweet cherry cultivars for their antioxidant and antiradical capacity and total phenolic and anthocyanin contents. Ukrainian cultivars had significantly higher ferric reducing antioxidant power and total phenolic contents compared with commercial cultivars. Levels of all four parameters varied considerably in the Ukrainian germplasm, with some cultivars having outstanding values. A total of eight different self-incompatibility genotypes were assigned to the 14 accessions tested. Assigning cultivars to the appropriate incompatibility groups allowed the design of parental combinations which may result in new genotypes with enhanced functional properties and other valuable fruit traits. Based on the S-genotypes, parental combinations were proposed to ensure 50 or 100 % self-compatible seedlings in the offspring population. The most perspective Ukrainian cultivars like ‘Dagestanka’ and ‘Kodrinskaya’ also had reasonable fruit weight (over 8 g), high flesh to pit ratio (approx. 18) and soluble solid contents (over 16 %). Our results demonstrated that adequate variation is available in Ukrainian germplasm for improving fruit health benefits in sweet cherry through directed hybridizations.     

Clone identification in Japanese flowering cherry (Prunus subgenus Cerasus) cultivars using nuclear SSR markers

Numerous cultivars of Japanese flowering cherry (Prunus subgenus Cerasus) are recognized, but in many cases they are difficult to distinguish morphologically. Therefore, we evaluated the clonal status of 215 designated cultivars using 17 SSR markers. More than half the cultivars were morphologically distinct and had unique genotypes. However, 22 cultivars were found to consist of multiple clones, which probably originate from the chance seedlings, suggesting that their unique characteristics have not been maintained through propagation by grafting alone. We also identified 23 groups consisting of two or more cultivars with identical genotypes. Most members of these groups were putatively synonymously related and morphologically identical. However, some of them were probably derived from bud sport mutants and had distinct morphologies. SSR marker analysis provided useful insights into the clonal status of the examined Japanese flowering cherry cultivars and proved to be a useful tool for cultivar characterization.     

Strawberry cultivar identification based on hypervariable SSR markers

We genotyped strawberry cultivars by two newly selected and two previously reported SSR markers. All four markers produced interpretable electropherograms from 75 accessions consisting of 72 Fragaria × ananassa cultivars or lines and three octoploid Fragaria species accessions. These SSR markers were highly polymorphic; in particular, one of the newly developed markers, FxaHGA02P13, was capable of distinguishing all of the accessions except for a mutant strain that was derived from another accession in the set. When two markers were combined, all 48 full-sib individuals could be distinguished. Fingerprinting patterns were reproducible between multiple samples, including the leaves, sepals, and fruit flesh of the same accession. Principal-coordinate analysis of the 75 accessions detected several groups, which reflect taxon and breeding site. Together with other available markers, these SSR markers will contribute to the management of strawberry genetic resources and the protection of breeders’ rights.     

磨盘柿叶片、果实及萼片中酚类物质的动态变化初报

磨盘柿（Diospyros kaki L. f. cv. Mopan）,是中国北方主要栽培的涩柿品种。在此,对其叶片、果实及萼片中的酚类物质含量在多个发育时期进行了测定,结果表明：在生长期内,柿萼片中的酚类物质含量呈上升趋势,与果实酚类物质含量变化规律完全不同;叶片的酚类物质含量均高于果肉的酚类物质含量;结果梢叶片与营养梢叶片酚类物质的含量变化不同,8月下旬以前,结果梢叶片的值大于营养梢叶片的,8月下旬以后,前者又小于后者。     

Identification of QTLs for fruit quality traits in Japanese apples: QTLs for early ripening are tightly related to preharvest fruit drop

Many important apple (Malus × domestica Borkh.) fruit quality traits are regulated by multiple genes, and more information about quantitative trait loci (QTLs) for these traits is required for marker-assisted selection. In this study, we constructed genetic linkage maps of the Japanese apple cultivars ‘Orin’ and ‘Akane’ using F₁ seedlings derived from a cross between these cultivars. The ‘Orin’ map consisted of 251 loci covering 17 linkage groups (LGs; total length 1095.3 cM), and the ‘Akane’ map consisted of 291 loci covering 18 LGs (total length 1098.2 cM). We performed QTL analysis for 16 important traits, and found that four QTLs related to harvest time explained about 70% of genetic variation, and these will be useful for marker-assisted selection. The QTL for early harvest time in LG15 was located very close to the QTL for preharvest fruit drop. The QTL for skin color depth was located around the position of MYB1 in LG9, which suggested that alleles harbored by ‘Akane’ are regulating red color depth with different degrees of effect. We also analyzed soluble solids and sugar component contents, and found that a QTL for soluble solids content in LG16 could be explained by the amount of sorbitol and fructose.     

Magnitude of inbreeding depression and genetic variation analysis of agro‐morphological traits in orchardgrass

Inbreeding depression is the reduction in the fitness of inbred offspring relative to progeny from unrelated parents. In orchardgrass (Dactylis glomerata L.), limited efforts have been made to evaluate the effects of deliberate selfing on agro‐morphological traits and to estimate the genetic variation of traits. Twenty‐five genotypes of orchardgrass, along with 25 S₁ (full‐sibs) and 25 families of half‐sibs, were created in 2012 and used to assess the consequences of the first generation of inbreeding and outcrossing for offspring fitness and to estimate heritabilities, genetic parameters and correlations of agro‐morphological traits during the period of 2013–2014 in the field. Different levels of inbreeding depression were observed for the traits, with higher values for plant height, days to inflorescence emergence and dry matter yield. The degree of inbreeding or outbreeding effects varied among the studied genotypes. This facilitates the development of inbred lines for further studies. The results showed that some of the studied genotypes were self‐fertile, thereby indicating the possibility of developing inbred lines from these genotypes. Heritabilities ranged from 0.10 for the number of stems per plant to 0.64 for spread among the studied populations. Spread had high heritability as well as high correlation with forage yield, thereby indicating that this trait could be used to improve forage yield indirectly.     

Molecular mechanism of the S-RNase-based gametophytic self-incompatibility in fruit trees of Rosaceae

Self-incompatibility (SI) is a major obstacle for stable fruit production in fruit trees of Rosaceae. SI of Rosaceae is controlled by the S locus on which at least two genes, pistil S and pollen S, are located. The product of the pistil S gene is a polymorphic and extracellular ribonuclease, called S-RNase, while that of the pollen S gene is a protein containing the F-box motif, SFB (S haplotype-specific F-box protein)/SFBB (S locus F-box brothers). Recent studies suggested that SI of Rosaceae includes two different systems, i.e., Prunus of tribe Amygdaleae exhibits a self-recognition system in which its SFB recognizes self-S-RNase, while tribe Pyreae (Pyrus and Malus) shows a non-self-recognition system in which many SFBB proteins are involved in SI, each recognizing subset of non-self-S-RNases. Further biochemical and biological characterization of the S locus genes, as well as other genes required for SI not located at the S locus, will help our understanding of the molecular mechanisms, origin, and evolution of SI of Rosaceae, and may provide the basis for breeding of self-compatible fruit tree cultivars.     

Distribution of photoperiod-insensitive alleles Ppd-B1a and Ppd-D1a and their effect on heading time in Japanese wheat cultivars

The genotypes of photoperiod response genes Ppd-B1 and Ppd-D1 in Japanese wheat cultivars were determined by a PCR-based method, and heading times were compared among genotypes. Most of the Japanese wheat cultivars, except those from the Hokkaido region, carried the photoperiod-insensitive allele Ppd-D1a, and heading was accelerated 10.3 days compared with the Ppd-D1b genotype. Early cultivars with Ppd-D1a may have been selected to avoid damage from preharvest rain. In the Hokkaido region, Ppd-D1a frequency was lower and heading date was late regardless of Ppd-D1 genotype, suggesting another genetic mechanism for late heading in Hokkaido cultivars. In this study, only 11 cultivars proved to carry Ppd-B1a, and all of them carried another photoperiod-insensitive allele, Ppd-D1a. The Ppd-B1a/Ppd-D1a genotype headed 6.7 days earlier than the Ppd-B1b/Ppd-D1a genotype, indicating a significant effect of Ppd-B1a in the genetic background with Ppd-D1a. Early-maturity breeding in Japan is believed to be accelerated by the introduction of the Ppd-B1a allele into medium-heading cultivars carrying Ppd-D1a. Pedigree analysis showed that Ppd-B1a in three extra-early commercial cultivars was inherited from ‘Shiroboro 21’ by early-heading Chugoku lines bred at the Chugoku Agriculture Experimental Station.     

Estimation of the proportion of offspring having soluble solids content in fruit exceeding a given critical value in Japanese persimmon

In fruit breeding, the selection is often based on individual plant performance, therefore, the expected proportion of offspring having genotypic values exceeding a given critical value (EP) was estimated for soluble solids content (SSC) in Japanese persimmon (Diospyros kaki Thunb.). A simple model was used in the study: the mean value of offspring in a full-sib family is solely determined by the regression of that on midparental value (MP) and all families have an equal within-family variance due to segregation. The population consisted of 39 full-sib families with three offspring each. Between-family variance was much smaller than within-family variance. Genetic variance for MP was much smaller than that for offspring. The EP therefore was not highly affected by the regression. Based on the parental mean performance of 35 fruits on a single tree for three years, the proportion of offspring having SSC higher than 18% was estimated as 32%, 50% and 69% for three groups of MP differing in SSC, i.e. 16.5%, 17.5%, and 18.5%, respectively. The distributions which were predicted using those results for 246 offspring from 46 families, and 86, 44, 43 and 31 offspring from four selected families, respectively, were largely consistent with those observed.     

Evaluation of genetic diversity among commercial cultivars, hybrids and local mango (Mangifera indica L.) genotypes of India using cumulative RAPD and ISSR markers

An assessment of genetic diversity studies was undertaken to understand the level and pattern of diversity in 65 mango (Mangifera indica L.) genotypes of India including 20 commercial cultivars, 18 hybrids, 25 local genotypes and two exotic cultivars based on qualitative and quantitative fruit characters as well as RAPD and ISSR profiles. A considerable variation was observed in respect of three important qualitative characters namely table quality, fruit attractiveness and storage life of ripe fruits and potentially superior genotypes for the above traits were identified. A wide variation was noticeable regarding metabolite composition of pulp of ripe mango fruit with respect to total soluble solids, total sugar, reducing sugar, acidity, sugar:acid ratio, ascorbic acid and phenolic content. Fifteen RAPD primers yielded 27 monomorphic and 129 polymorphic bands with percent polymorphism averaging 82.7%. Of a total 70 ISSR bands generated from eight ISSR primers, 60 bands (85.71%) were found to be polymorphic. Cumulative band data from these two methods precisely arranged accessions into eight clusters which correspond well with their pedigree relationship. UPGMA dendrograms drawn using RAPD, ISSR and cumulative data showed highly similar grouping of genotypes on the basis of their parental origin. No clear-cut geographical separation was revealed among East, West, North and South Indian mango cultivars by neither of these molecular markers nor their combinations. This supports the common gene pool origin of mango as well as operation of similar selection pressure as the cultivar preferences in these areas are largely similar.     

Identificaiton of a clubroot resistance locus conferring resistance to a Plasmodiophora brassicae classified into pathotype group 3 in Chinese cabbage (Brassica rapa L.)

In Chinese cabbage (Brassica rapa), the clubroot resistance (CR) genes Crr1 and Crr2 are effective against the mild Plasmodiophora brassicae isolate Ano-01 and the more virulent isolate Wakayama-01, but not against isolate No. 14, classified into pathotype group 3. ‘Akiriso’, a clubroot-resistant F₁ cultivar, showed resistance to isolate No. 14. To increase the durability of resistance, we attempted to identify the CR locus in ‘Akiriso’. CR in ‘Akiriso’ segregated as a single dominant gene and was linked to several molecular markers that were also linked to CRb, a CR locus from cultivar ‘CR Shinki’. We developed additional markers around CRb and constructed partial genetic maps of this region in ‘Akiriso’ and ‘CR Shinki’. The positions and order of markers in the genetic maps of the two cultivars were very similar. The segregation ratios for resistance to isolate No. 14 in F₂ populations derived from each of the two cultivars were also very similar. These results suggest that the CR locus in ‘Akiriso’ is CRb or a tightly linked locus. The newly developed markers in this study were more closely linked to CRb than previously reported markers and will be useful for marker-assisted selection of CRb in Chinese cabbage breeding.     

Changes in the microstructure and location of some bioactive compounds in persimmons treated by high hydrostatic pressure

Persimmon fruit are an important source of phenolic compounds, dietary fibre, and carotenoids. However, the location of these elements in the tissue is directly connected with processing techniques used. The aim of this work was to study the effect of high hydrostatic pressure (HHP) on the microstructure of persimmon fruit cv. ‘Rojo Brillante’ during different ripening stages and the relationship of this treatment with changes in the location of some bioactive compounds. Samples from persimmon fruit cv. ‘Rojo Brillante’ from two ripening stages, with and without deastringency treatment (95–98% CO₂), were treated by HHP at 200 and 400 MPa during 1, 3, and 6 min. A microstructural study using cryo-scanning electron microscopy, light microscopy, and confocal laser scanning microscopy (Cryo-SEM, LM, and CLSM) was carried out. Total soluble solid (TSS) content and some textural properties were also analyzed. The microstructural study showed that application of HHP caused cell wall disruption and intracellular component dispersion throughout the tissue, together with some nutritionally interesting compounds (tannins, fibres, and carotenoids). TSS content diminished in astringent samples when HHP was applied. This was attributed to precipitation of soluble tannins, which are responsible for fruit astringency. Therefore, it might be possible to omit a deastringency treatment with CO₂ before HHP treatments. HHP treatments caused an overall decrease in firmness for both ripening stages and an increase in cohesiveness (TPA analysis) in the more advanced stage.     

Validation of a male‐linked gene locus (OGI) for sex identification in persimmon (Diospyros kaki Thunb.) and its application in F1 progeny

It is crucial to develop a rapid technique for identifying sexuality in the seedling stage of persimmon (Diospyros kaki Thunb.), and the elimination of male progeny has been regarded as an important strategy for enhancing breeding efficiency. In this study, phenotype characterization and genotyping of the male‐linked OGI marker were carried out using 205 accessions, including persimmon cultivars, F₁ progeny and nine related Diospyros species. All persimmon cultivars displayed consistent results regarding OGI amplification and sex phenotype. A total of 143 F₁ progeny were derived from 11 crosses, among which 95 individuals had flowered. In the flowering full‐sib families, the amplification of the OGI marker in agreement with the sex phenotype was obtained in 85 plants (89.5%). The segregation of OGI in ‘Huashi 1’ × ‘Luotian Tianshi’ and ‘Huashi 1’ × Male 3 F₁ populations fit a 1 : 1 ratio. Furthermore, high OGI transferability was observed in nine related species. Overall, the results indicated that the OGI locus could be used to distinguish male from female persimmon plants at an early stage.     

Genetic relatedness among eastern North American blackberry cultivars based on pedigree analysis

Blackberry genetic relationships (Rubus subgenus Rubus Watson) have not been thoroughly studied. The University of Arkansas maintains one of the largest blackberry-breeding programs in the world and thus, in-depth knowledge of the cultivars released from the program and others instrumental in their lineages can aid in breeding endeavors. Pedigrees of 32 cultivars were traced to their founding clones. Genetic contribution (GC), maximum potential similarity (MPS), inbreeding coefficient, and coefficients of relationship (CR) were calculated for all genotypes. Nineteen founding clones contributed to the 32 cultivars, ranging from <1% to 19%. The top three founding clones for mean GC conferred nearly 50% to the 32 cultivars in this study, suggesting a somewhat narrow genetic base. Calculations for MPS ranged from complete similarity (1.00) to 0.00. Individual inbreeding coefficients ranged from 0.00 to 0.25. The coefficient of relationship was used as a method of determining genetic relatedness and ranged from 0.00 to 0.74. University of Arkansas cultivars had the highest MPS and CR in the study. This may be attributed to more generations of hybridization than the other cultivars. The MPS provided some comparable results to those of RFLP and RAPD molecular studies, but CR did not. The rather narrow genetic base of eastern North American blackberry cultivars does not create an imminent, significant concern for loss of diversity. However, more diverse germplasm should be infused for continuation of heterogeneity.     

Effect of inbreeding and growth regulators on the in vitro androgenesis of wheatgrass, Agropyron glaucum

The capacity of haploid production by anther culture has been analysed in 42 crossbred genotypes (wild type) and in 32 genotypes from inbreeding generations (I₂-I₃) of wheatgrass, Agropyron glaucum. On potato-2 medium, about 50% of the genotypes investigated were capable of embryoid and callus induction. For the regeneration of haploid plants, five media containing various growth regulators were used. The crossbred genotypes were superior to the inbred lines in all the androgenesis parameters examined.     

DNA markers linked to Pga1, an adzuki bean gene that confers resistance to Cadophora gregata race 1

Brown stem rot (BSR) caused by Cadophora gregata f. sp. adzukicola (syn. Phialophora gregata) is a serious soilborne disease of adzuki bean (Vigna angularis) in Japan. Cultivation of resistant cultivars is the most effective disease control method, therefore the selection of resistant lines is a priority for breeders. BSR-resistant adzuki bean lines have been screened in pathogen-infected fields. However, field selection using the pathogen and artificial inoculation methods is time-consuming and labor-intensive. In the present study, we used 105 F₃ lines derived from a cross between a BSR-resistant cultivar ‘Syumari’ and a susceptible cultivar ‘Buchishoryukei-1’ for BSR inoculation tests. Amplified fragment-length polymorphism (AFLP) analyses with 1024 primer sets revealed that six fragments were polymorphic between resistance and susceptible bulked groups. Five DNA markers (Pg77, Pg118, Pg138, Pg139 and Pg126) were developed from the nucleotide sequences of polymorphic AFLP markers and their flanking regions. Pg118, which was derived from E-ACT/M-ACT-118, was tightly linked to the resistance gene Pga1 and was converted into a codominant marker for its easier use in marker-assisted selection for adzuki bean BSR resistance. Finally, the applicability of the developed markers for BSR resistance was tested on 32 adzuki bean accessions or cultivars.     

Little heterosis for yield and yield components in hybrids of six cucumber inbreds

Heterosis and inbreeding depression for fruit yield has been reported for pickling cucumber (Cucumis sativus L.). However, cucumber inbreds often perform as well as hybrids, and there is little inbreeding depression. The objectives of this study were to reexamine the amount of heterosis and inbreeding depression for fruit yield and yield components in pickling cucumber, and to determine the relationship between yield components and yield for heterosis. Two pickling cucumber inbreds (M 12, M 20) and inbreds from four open-pollinated monoecious cultivars (‘Addis’, ‘Clinton’, ‘Wisconsin SMR 18’, ‘Tiny Dill’) were hybridized to form four F₁ hybrids (‘Addis’ × M 20, ‘Addis’ × ‘Wis. SMR 18’, ‘Clinton’ × M 12, M 20 × ‘Tiny Dill’). F₁ hybrids were then self-pollinated or backcrossed to generate F₂, BC_1A, and BC_1B progeny. Thirty plants of each generation within each hybrid family were grown in plots 3.1 m long with four replications in each of two seasons. Data were collected from once-over harvest for vegetative, reproductive, yield, and fruit quality traits. Heterosis and inbreeding depression for fruit yield and yield components were not observed in three of the hybrids. Only ‘Addis’ × ‘Wis. SMR 18’ exhibited high-parent heterosis and inbreeding depression for total, marketable, and early fruit weight. For ‘Addis’ × ‘Wis. SMR 18’, heterosis for fruit yield was associated with a decreased correlation between percentage of fruit set and fruit weight, an increased negative correlation between percentage of fruit set and both the number of branches per plant and the percentage of pistillate nodes, and an increased negative correlation between the number of nodes per branch and total fruit weight. Inbreeding depression was associated with a weakening of the strong negative correlations between percentage of fruit set and the number of branches per plant, and between the number of nodes per branch and total fruit weight. Those correlations were associated with high-parent heterosis and inbreeding depression only for one cross, and do not necessarily apply to future crosses in which heterosis may be observed for yield. We did not observe the heterosis or inbreeding depression for yield in cucumber in most of the crosses as was reported by Ghaderi & Lower (1979a; 1979c). This revised version was published online in August 2006 with corrections to the Cover Date.