仁用杏离体培养技术

本项目主要研究仁用杏离体培养技术,为仁用杏遗传转化提供良好的再生体系。本试验以仁用杏品种‘围选1号’和‘优一’为试验材料,在仁用杏休眠期对其1年生枝进行短截和长放两种修剪处理。分别于5月、6月、7月、8月、9月上旬采集外植体,研究修剪、外植体采集时期、以及外源激素等因素对仁用杏离体培养的影响。结果表明:5、6月份采集外植体,仁用杏品种‘围选1号’和‘优一’的茎段腋芽的诱导率较高,同时短截处理茎段腋芽的诱导率高于长放处理;8、9月份采集外植体,茎段腋芽的诱导率较低,同时短截处理与长放处理相比较,茎段腋芽的诱导率无明显差异。外源激素6-BA、NAA有利于仁用杏品种‘围选1号’和‘优一’茎段腋芽的诱导、生长与分化。培养基中添加1.0 mg/L 6-BA、0.1 mg/LNAA时,茎段腋芽诱导率最高,组培苗生长最健壮。本研究结果为仁用杏离体培养提供科学数据,进而为仁用杏的基因工程育种提供帮助。     

Phenotypic diversity and relationships of fruit quality traits in apricot (Prunus armeniaca L.) germplasm

Fruit quality attributes were studied for two consecutive years in forty-three apricot cultivars and selections grown in a Mediterranean climate. Physical parameters (weight, size, flesh and skin colour, percentage of blush, firmness and percentage of dry matter), chemical parameters (total soluble solids content and acidity) and sensory parameters (attractiveness, taste, aroma and texture) were evaluated. A high variability was found in the set of the evaluated apricot genotypes and significant differences were found among them in all studied quality attributes. Year-by-year variations were observed for some pomological traits such as harvest date, flesh colour, fruit weight, firmness and soluble solids content. A high correlation was found among some apricot quality attributes. In addition, principal component analysis (PCA) made it possible to establish similar groups of genotypes depending on their quality characteristics as well as to study relationships among pomological traits in the set of apricot genotypes evaluated.     

New self-incompatibility alleles in apricot (Prunus armeniaca L.) revealed by stylar ribonuclease assay and S-PCR analysis

Apricot (Prunus armeniaca L.) shows gametophytic self-incompatibility controlled by a single locus with several allelic variants. An allele for self-compatibility (S_C) and seven alleles for self-incompatibility (S₁–S₇) were described previously. Our experiments were carried out to ascertain whether the number of allelic variants of apricot S-locus was indeed so small. Twenty-seven apricot accessions were analysed for stylar ribonucleases by non-equilibrium pH gradient electrofocusing (NEpHGE) to determine their S-genotype. To validate the results of electrofocusing, the applicability of the S-gene-specific consensus PCR primers designed from sweet cherry sequences was tested. NEpHGE revealed 12 bands associated with distinct S-alleles in newly genotyped cultivars. Cherry consensus primers amplified 11 alleles out from 16 ones, which indicated that these primers could also recognize most of the S-RNase sequences in apricot, and provided an efficient tool to confirm or reject NEpHGE results. By combining the protein and DNA-based methods, complete or partial S-genotyping was achieved for 23 apricot accessions and nine putatively new alleles (provisionally labelled S₈–S₁₆) were found. Their identity needs to be confirmed by pollination tests or S-allele sequencing. This study provides evidence that similarly to other Prunus species, the S-locus of apricot is more variable than previously believed.     

Self-incompatibility in Spanish clones of apricot (Prunus armeniaca L.) tree

The present study is about some aspects of the reproduction physiology of twenty apricot clones ( Prunus armeniaca L.) grown in Abarán (Murcia, Spain). Self incompatibility of these clones was determined not only in field conditions in terms of the fruit set by means of self fertilization and free pollination, but also in laboratory conditions, by means of fluorescence microscopy of pollen germination on the stigma and of the growth of the pollen tube towards the egg. The only clone with signs of self incompatibility was ‘Moniquí Azaraque’. The clone with the lowest fertilization time was ‘Chicanos Archena’. This revised version was published online in July 2006 with corrections to the Cover Date.     

Patterns and heritability of carboxylic acids and soluble sugars in fruits of apricot (Prunus armeniaca L.)

The investigation of acid and sugar content in an array of apricot cultivars and progenies indicates the existence of marked variability. Citric acid varied from 0.17 to 1.20% and malic acid from 0.21 to 1.51% on fresh weight. Fructose varied from 0.27 to 1.60%, glucose from 0.90 to 3.13% and sucrose from 1.92 to 6.92%. The estimate of heritability was high for total and main sugars, reaching over 0.50%. Acids generally showed low coefficients, although those for citric (0.27) and malic (0.36) were good. With the exception of one progeny, all genotype/year comparisons were not significant, showing constant patterns for acid and sugars over the years regardless of the variability in absolute values. This means that the patterns of each genotype are under genetic control. The wide range of diversity in acid and sugar content in apricot germplasm and the independent heritability for most of these compounds make it possible to breed and select cultivars with improved flavour on the basis of superior phenotypes.     

A marker-assisted analysis of bolting tendency in sugar beet (Beta vulgaris L.)

Bolting tendency in sugar beet varies among breeding lines and cultivars. Four crosses were made between breeding lines susceptible and resistant to bolting in order to study the genetic basis of bolting tendency. Bolting percentage in F₂, after 8 weeks of low temperature treatment, varied among the crosses, suggesting a complicated genetic control of bolting tendency. Different segregation ratios were observed, in particular, between families derived from the bolting F₁ plants and those from their non-bolting siblings, the former families showing a significantly higher bolting percentage than the latter. A marker-assisted analysis with seven isozyme loci, Ak1, Gdh2, Idh1, Lap, Mdh1, Pgi2 and Pgm1, revealed that a locus with marked effect on bolting tendency was located near Idh1. Because of a close linkage of Idh1 with B for annuality, the gene tagged by Idh1 appeared to be equivalent or similar to B′ for easy bolting allelic to B as reported by Owen et al. (1940). The results obtained suggest that the B locus may not only have an important role in determining growth habits but also control various degrees of bolting tendency in individual sugar beet plants. A linked pair, Ak1-Lap, and Pgi2 also were found to affect bolting tendency, although their effects varied depending on the crosses and families tested. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effect of in planta TIBA and proline treatment on somatic embryogenesis of sugar beet (Beta vulgaris L.)

The effect of in planta TIBA and L-proline onin vitro seedlings and cell culture of sugar beet was investigated. Sterilized seeds were grownin vitro on 1/2 MS medium supplemented with 0 or3 mg/l TIBA. Calli obtained on young leaves cultured on MS medium containing 1 mg/l BAP, were used for the initiation of cell suspension cultures using MS basal composition supplemented with 0 or 50 mM proline. Aliquots of 1 ml from cell suspension culture were inoculated onto the first somatic embryo induction MS medium containing TIBA 0.5 mg/l, BAP 1.0 mg/l, and proline at 0 or 50 mM. After three weeks of culture, embryogenic calli were transferred to the second embryo induction medium supplemented with NAA and BAP at 0.2 and 0.5 mg/l, respectively. The frequency of somatic embryos of calli obtained from in plantaTIBA together with proline treatments on average was20 which was higher than that of the other treatments. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic study of bolting and stem length in sugar beet (Beta vulgaris L.) using a factorial cross design

Summary The objective was to study the genetic basis of bolting and stem length in sugar beet full-sibs, developed by a factorial mating design (N.C. design II). The extent to which the inheritance of these characters can be attributed to the additive and non-dominance variation was investigated. The genetic analysis consisted of three sets (4×10, 4×8, and 3×8) of progenies. Estimates of additive genetic variance (² _A) and variance due to dominance deviations with some fractions of epistatic variance (² _D) were obtained for both characters. Bolting had a relatively large proportion of total genetic variance accounted for by ² _A. In most cases, non-additive effects were also important in determining the type of gene action in bolting. Stem length showed similar genetic variation to bolting susceptibility. Bolting resistance seemed to be dominant to the bolting susceptibility in most cases. Narrow sense heritability estimated for bolting was generally very large (0.93 to 0.96), which suggests that early generation selection for bolting resistance in a sugar beet population would be successful.     

Efficient application of in vitro anther culture for different European winter wheat (Triticum aestivum L.) breeding programmes

The efficiency of our anther culture protocol was tested with high‐ and low‐responding genotypes, ‘Svilena’ and ‘Berengar’, and 93 F₁ winter wheat crosses in 2010 and 2011. Based on data for these genotypes, the effect of genotype influenced the number of embryo‐like structures, regenerated plantlets and green plantlets, while the number of albino plantlets was affected by genotype, year and environmental factors. Although genotype also influenced the production of green plantlets from breeding crosses, with green plantlets per 100 anthers ranging from 0.04 to 28.67, the average regeneration rate over all crosses was 5.3 green plantlets/100 anthers, which resulted in a total of 11 416 well‐rooted green plantlets. The survival rate of green plantlets following acclimatization was 97.21% in 2010 and 96.34% in 2011. In this study, the phenomenon of albinism and genotype dependency did not hinder the production of more than five thousand green plantlets each year. In our experiments, anther culture proved to be an efficient method in winter wheat breeding programmes with lower costs than alternative technologies.     

The efficiency of between and within full-sib family selection in a recurrent selection programme in sugar beet (Beta vulgaris L.)

The efficiency of between and within family selection in a full-sib family recurrent selection programme was investigated using data from three cycles of recurrent selection. Correlations between mid-parent values and offspring were high for sugar content and juice purity characters, but low for root weight and sugar yield. This suggests that single root selection within full-sib families is effective in the improvement of sugar content and juice purity, but ineffective for root weight and sugar yield. Root weight and sugar yield will respond better to between full-sib family selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Correlation between polyovules and number of pistil lobes (stigmatic rays) in sugar beet (Beta vulgaris L.)

The polyovules phenomenon in sugar beet has the same importance for breeding as multigermity, because only mono-ovulic monogerm plants can be used for mechanized cultivation. The polyovules trait was investigated in two Japanese lines, mono-ovulic line NK-219-O and polyovulic line NK-183-cms. Plants of the former had three pistil lobes (stigmatic rays) in each flower, a single ovule per ovary, a single seed in the mature fruit and a single seedling germinated in subsequent tests. Plants of the latter had 5–6 pistil lobes in each flower, 2–3 ovules per ovary, double-seeds and double-seedlings. The correlations between a Pistil Lobes Index (PLI) and thenumber of ovules per ovary, percentage of double-seeds inan X-ray test, and percentage of double-seedlings in germination tests were 0.885, 0.838, and 0.749, respectivelyindicating close associations. These results are important both in sugar beet breeding for indirect selection to eliminate the undesirable polyovules trait and for botanicalinvestigations of the relationship among different parts of the gynoecium.     

Recurrent breeding method enhances the level of blackspot (Didymella pinodes (Berk. & Blox.) Vestergr.) resistance in field pea (Pisum sativum L.) in southern Australia

Blackspot, caused by Didymella pinodes (Berk. & Blox.)Vestergr., is one of the most important diseases of field pea, causing significant reduction in seed yield and quality in southern Australia and in other parts of the world. Development of resistant germplasm has been slow because of the low level of resistance found in the available germplasm, poor reliability of screening methods and the polygenic nature of inheritance. Crosses were made between agronomically suitable lines and resistant germplasm from different sources. Their progeny were advanced through the single seed descent method and single plants were selected at F₄/F₅. The F₄/F₅ derived lines were screened against blackspot in the field under disease pressure and evaluated for grain yield at multilocations over 2 years. Despite the low level of resistance in the parental germplasm, the level of resistance has increased significantly in the new germplasm. Many of the resistant lines were late and low yielding, but lines with higher resistance and early flowering and high yield potential were also identified indicating that the disease resistance, adaptation and yield potential can be combined. However, the resistance identified in this study is only partial and suitable agronomic practices may need to be supplemented to minimise the yield loss and enhance the benefits of this partial resistance.     

Simultaneous improvement in cold tolerance and yield of temperate japonica rice (Oryza sativa L.) by introgression breeding

To combine high yield and improved cold tolerance (CT) in a japonica rice variety, ‘Chaoyou1’ (CY1), 324 BC₂F₅ introgression lines (ILs) selected for CT from 11 CY1 BC₂F₄ populations were evaluated in replicated experiments for their CT at the reproductive and seedling stages. A mean realized heritability of 0.747 was achieved in this study for CT. Evaluation of 116 ILs from five BC populations in replicated experiments under stress and normal conditions identified 18 promising ILs that had greatly improved CT and yield compared with CY1. Detailed comparisons between the ILs and CY1 for CT and yield‐related traits under stress and non‐stress conditions provided useful information and better understanding of important issues such as donor selection, selection efficiency and associated changes in non‐target traits in the BC breeding process. The large numbers of CT ILs developed provide useful materials for genetic, physiological and molecular dissection of CT and yield traits using DNA markers and ‐omic tools, and as parents for further improving these traits by designed QTL pyramiding.     

Flow cytometric identification of sexually derived polyploids in hop (Humulus lupulus L.) and their use in hop breeding

The New Zealand hop breeding programme is based solely on the development of seedless triploid cultivars. This relies on the use of tetraploid parents. While a sexually derived tetraploid parents have been used successfully, sexually derived tetraploids offer a useful alternative. They may have a higher level of heterozygosity and are easier to obtain. Methods for the identification of tetraploids from seedling populations by flow cytometry are described. Two studies were conducted; one on field-grown plants, the other on plants grown in a glasshouse. Approximately 15%of seedlings in the two studies were identified as tetraploids (2n = 4x = 40). Between 70 and 80% were identified as either diploid (2n =2x = 20) or triploid (2n = 3x = 30). Remaining plants were haploid, pentaploid or probably aneuploid. Within triploid and tetraploid populations from 40to 50% of seedlings were female, 30 to40% were monoecious, with the remainder being males and non-flowering plants. Sexually derived tetraploid parents have been used successfully in the breeding programme, from which several promising triploid selections have subsequently been made. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development of a new initial breeding material in sunflower (Helianthus annuus L.) using direct organogenesis and somatic embryogenesis

Summary Immature zygotic embryos from three inbred lines of sunflower (Helianthus annuus L.) were used as donor material for the induction of direct organogenesis and somatic embryogenesis. The scope of the spontaneously appearing somaclonal variation has been studied among the regenerants produced according to the method of Freyssinet & Freyssinet (1988), and was compared to the results obtained after gamma ray mutagenesis (7 and 10 Gy). Freshly excised immature zygotic embryos were used for irradiation treatment. Genetic changes occurring spontaneously during the regeneration procedure were observed for date of flowering, vegetation period, plant height, head diameter, 1000 seed weight, kernel oil content, and fatty acid composition. The mutagenic treatment had a marked stimulatory effect on the frequency of the regenerants produced and the degree of the observed changes. The 7 Gy treatment was most efficient for the majority of the characters studied. The type of changes was correlated with the genotype. The degree and type of somaclonal variation, with or without mutagenic treatment, should be sufficient for an application in the production of new breeding material.     

Inheritance of tree and fruit characters in progenies from crosses of sweet cherry (Prunus avium L.) cultivars

Summary Approximately 1000 seedlings from 20 combinations crossed in 1979, 1980 and 1981 (Theiler-Hedtrich 1985a) were tested for several characters: fruit set (yield), fruit size, fruit colour, formation of abscission layer and bleeding after fruit removal from fruit stalks, bacterial canker resistance, flowering and harvesting time. From progeny of crosses with Stella as pollinator, 56% (Vittoria × Stella) and 46% (Schüttler × Stella) of the seedlings were self-compatible, of which 14 were high yielding with good fruit size and quality. From the data recorded it can be concluded:fruit set is a recessive character; only 5 to 20% of very good yielding seedlings were obtained in different progeny, even if the parental plants were both very good croppers.Fruit juice and skin colour was in most progenies ‘black’ even if they were from combinations with ‘white’ varieties, e.g., Merton Glory or Schüttler. Only from the combination Schiittler (‘white’) × Stella (‘black’), 50% of the seedlings were ‘white’; Stella therefore is heterozygous for the character of fruit juice and skin colour.Fruit size is evenly distributed in progeny with respect to the fruit size of their parent plants.Abscission layer formation and non-bleeding is a genetically complex character. In combinations where both parent plants formed fruits with complete abscission layers and which were not bleeding after fruit removal from the stalk, this character was inherited only to 50% (Vittoria × Schüttler) or 85% (Vittoria × Frühe von der Weid) in the progeny. For the genetical control of this character further studies are necessary.Bacterial canker susceptibility was evenly distributed in seedlings from all combinations even if the highly resistant cv. Vittoria was used as one parent plant, thereby not confirming the expected results of a higher proportion of resistant seedlings from combinations with Vittoria.Flowering and harvest time of the seedlings from different combinations was within the range of the parent plants. Only in the combination of Vittoria × Stella (mid-to late-ripening season) one seedling out of 99 was found to form ripe fruits two weeks earlier than the parental plants. From the seedlings tested 40 have been chosen for further evaluation or genetical studies.     

The relation between grain yield and some related traits of spring barley (Hordeum vulgare L.) and their usefulness in a breeding program

Summary The objective of this study was to evaluate traits which can facilitate and improve selection for grain yield of spring barley. Five experiments were conducted in different environments to measure grain yield and yield related traits of breeding lines and exotic varieties. Differences for rate of canopy expansion were significant and offer the opportunity to select for a high weed suppressing potential but there was no relation to grain yield. Dry matter yield/m² at anthesis and its water-soluble-carbohydrate content were not correlated with grain yield/m² and number of grains/m². Variation in biomass among breeding lines with a similar development and plant height was small. Biomass standardized for plant height was stable across environments and showed a good correlation with number of grains and grain yield. The contribution of pre-anthesis assimilation to grain yield was only important under low yielding experimental conditions, but the differences among the genotypes for this trait were inconsistent. It may be difficult to select genotypes with a high potential contribution of pre-anthesis assimilation to grain yield.     

Perspectives of breeding for resistance to ‘yellow disease’, Xanthomonas hyacinthi(Wakker)Dowson,in hyacinths (Hyacinthus L.)

Summary Since 1880 yellow disease has been known as a very serious disease in hyacinth. The breeding of resistant varieties can constitute an important contribution to the solution of this problem. Therefore it was first aseertained how the differences in resistance between the varieties can be determined as accurately as possible. To this end bulbs and plants of well known cultivars were inoculated with bacteria, and the degree of infection compared with that of bulbs grown in the field. It was found that the infection of the inoculated bulbs corresponded little, if at all, with infection in practice, but the infection of the inoculated leaves did. So the degree of leaf infection seems a useful selection criterion. Comparison of the infection of juvenile and adult plants also yielded an indication of the possibility of preselection for yellow disease resistance in seedling populations.     

Inheritance of parthenocarpy in pickling cucumbers (Cucumis sativus L.) and linkage with other characters

Summary The inheritance of parthenocarpy in the pickling cucumber has been studied with progenies of an incomplete diallel cross between lines with different degrees of parthenocarpy and with two sets of F₁, F₂ and B₁ of crosses between parthenocarpic and non-parthenocarpic lines. The inheritance of parthenocarpy could be explained by three independent, isomeric major genes with additive action, together with a non-allelic interaction of the homozygote-heterozygote type. Indications have been found for linkages between genes that govern parthenocarpy, femaleness and the spined/hairy fruit character. Consequences for breeding parthenocarpic varieties are discussed.