Performance of several models for predicting budburst date of grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

The budburst stage is a key phenological stage for grapevine (Vitis vinifera L.), with large site and cultivar variability. The objective of the present work was to provide a reliable agro-meteorological model for simulating grapevine budburst occurrence all over France. The study was conducted using data from ten cultivars of grapevine (Cabernet Sauvignon, Chasselas, Chardonnay, Grenache, Merlot, Pinot Noir, Riesling, Sauvignon, Syrah, Ugni Blanc) and five locations (Bordeaux, Colmar, Angers, Montpellier, Epernay). First, we tested two commonly used models that do not take into account dormancy: growing degree days with a base temperature of 10°C (GDD₁₀), and Riou’s model (RIOU). The errors of predictions of these models ranged between 9 and 21 days. Second, a new model (BRIN) was studied relying on well-known formalisms for orchard trees and taking into account the dormancy period. The BRIN model showed better performance in predicting budburst date than previous grapevine models. Analysis of the components of BRIN formalisms (calculation of dormancy, use of hourly temperatures, base temperature) explained the better performances obtained with the BRIN model. Base temperature was the main driver, while dormancy period was not significant in simulating budburst date. For each cultivar, we provide the parameter estimates that showed the best performance for both the BRIN model and the GDD model with a base temperature of 5°C.     

High-efficiency biolistic co-transformation and regeneration of 'Chardonnay' (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) containing<Emphasis Type="Italic"> npt-II</Emphasis> and antimicrobial peptide genes

A reliable and efficient system for transformation and regeneration of 'Chardonnay' (Vitis vinifera L.) plants via microprojectile bombardment was developed. Improvements over the previous biolistic transformation system included: (1) the use of gold particles for bombardment; (2) step-wise selection at 10 then 15 mg/l kanamycin; and (3) embryo induction at 27°C. Embryogenic cell cultures were either bombarded with pBI426, which contains the reporter gene gus (uidA) coding for -glucuronidase (GUS), or were co-bombarded with pSAN237 carrying the npt-II (neomycin phosphotransferase II) selectable marker gene, and a second plasmid with an antimicrobial peptide gene. A large number of transient (7,883±1,928) and stable (46±32) blue spots per plate at 2 and 95 days after bombardment, respectively, were obtained according to GUS expression analyses. A total of 447 putative transgenic embryos was harvested from 84 bombarded plates. From these embryos, 242 (54%) were regenerated into plants within the first year of the experiment. Southern blot analyses confirmed integration of the transgenes into the grape genome. Co-transformation was tested with four separate antimicrobial constructs. The co-transformation frequency of unlinked genes was 48% as measured by polymerase chain reaction (PCR), and 56% as estimated by dot blot hybridization. Expression of the gus gene, and PCR and Southern blot analyses of npt-II and antimicrobial genes from regenerated plants document stable transformation of 'Chardonnay' and establish the parameters for highly-efficient biolistic transformation in V. vinifera.Abbreviations AMP Antimicrobial peptide - DBH Dot blot hybridization - GM+NOA Glycerol and maltose liquid medium with -naphthoxyacetic acid - gus -Glucuronidase gene - GUS -Glucuronidase - Km Kanamycin - Km^R Kanamycin resistant - mag2 Magainin-2 - MS Murashige and Skoog medium - MS/2 Half-strength Murashige and Skoog medium - nos Nopaline synthase - npt-II Neomycin phosphotransferase II gene - PCR Polymerase chain reaction - PGL Peptidyl-glycine-leucine - Pubq3 Arabidopsis ubiquitin-3 promoter - Pubq10-L Arabidopsis ubiquitin-10L promoter - Pubq11 Arabidopsis ubiquitin-11 promoter - SP Signal peptide - Tnos Nopaline synthase terminator - WPM Woody plant mediumCommunicated by E.D. Earle     

Chitosan improves development,and protects<Emphasis Type="Italic"> Vitis vinifera</Emphasis> L. against<Emphasis Type="Italic"> Botrytis cinerea</Emphasis>

We evaluated the potential of chitosan both to stimulate plant development and to induce protection from Botrytis cinerea in Vitis vinifera L. plantlets. The presence of 1.75% (v/v) chitogel in the culture medium was the optimal concentration for in vitro grapevine plantlet growth, as determined by measurements on enhancement of root and shoot biomass. Photosynthesis and related parameters were also stimulated in chitogel-treated plantlets. Chitogel reduced the development of Botrytis cinerea and induced cytological alterations to the pathogen. When challenged with the fungus, a significant decrease in disease incidence was observed in plants growing on medium supplemented with chitogel. Furthermore, exogenous foliar applications of chitogel to plantlets growing on chitogel-free medium sensitized them so as to be protected against Botrytis cinerea attack. Our results indicate that chitogel can be used in the vineyard as a means to attain protection against Botrytis cinerea and that its application may counteract the wide use of chemical pesticides.Communicated by S. Gleddie     

Proteomic analysis of somatic embryogenesis in <Emphasis Type="Italic">Vitis vinifera</Emphasis>

Two dimensional gel electrophoresis coupled to mass spectrometry has been used to study the somatic embryogenesis in Vitis vinifera, by comparing embryogenic and non embryogenic calluses of the Thompson seedless cv. More than 1,000 spots were reproducibly resolved in colloidal Coomassie brilliant blue stained gels over a pI nonlinear range of 3–10 in the first dimension and using homogeneous 12.5% polyacrylamide gels in the second dimension. The expression pattern of 35 spots differed significantly between the two samples. These spots were processed by mass spectrometry analysis and the protein identity was assigned by using both the non-redundant protein and EST databases. Several responsive proteins, some already known to be involved in the somatic embryogenesis process while others, for the first time put into relation with this process, have been described. Moreover, they have been subdivided in functional categories, and their putative role is discussed in terms of their relevance in the somatic embryogenesis process.     

AFLP analysis of genetic relationships among aromatic grapevines (<Emphasis Type="Italic">Vitis vinifera</Emphasis>)

Genotypic diversity has been detected among aromatic grapevines (Vitis vinifera) by molecular markers (AFLPs). The 22 primer-pairs generated a total of 1,331 bands of which 564 (40%) were polymorphic over all the genotypes. The bootstrap analysis pointed out that a large number of polymorphic bands (200–400) has to be used for a better estimation of the genetic distances among genotypes; 383 polymorphic AFLP bands were used for the cluster and the principal coordinate analyses because they did not present missing data across all the genotypes. The cluster analysis (UPGMA), based on polymorphic AFLP markers, revealed no relationship between the Moscato and Malvasia grapevines. The Malvasias, unlike the Moscatos distinguished by their distinct muscat aroma, have to be considered a more complex group because it includes muscat and non-muscat grapevines. The principal coordinate analysis (PCO) confirmed the pattern of the cluster analysis only for those varieties which presented a low coefficient of dissimilarity, while for the other varieties there was no correspondence between the two analyses. The pattern of aggregation among aromatic grapevines in the cluster and principal coordinate analyses does not support any classification that might include an aromatic grapevine group in V. vinifera. Even though some synonyms and homonyms are present among aromatic grapevines (V. vinifera), genetic diversity exists among genotypes in AFLP markers.Communicated by H.F. Linskens     

An improved method for isolating high-quality DNA from<Emphasis Type="Italic">Vitis vinifera</Emphasis> nuclei

We have developed a simple and highly efficient protocol for isolating large quantities (150–400 μg/g leaf tissue) of high-quality DNA from fresh and frozenVitis vinifera leaves. Isolated DNA is essentially free of polysaccharides, polyphenols, and other major contaminants as judged by viscosity, clear color, A_260/280 ratio, digestibility by restriction enzymes for Southern blot analysis, and PCR suitability.     

Improved somatic embryogenesis of grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis>) with focus on induction parameters and efficient plant regeneration

A study of four parameters (induction medium, floral explant, developmental stage and year) was carried out to determine the best combination for the embryogenesis induction of eight grapevine (Vitis vinifera L.) cultivars. Anthers and ovaries were extracted from flower buds at three developmental phases and incubated in two induction media over two consecutive years. As average, the percentage of embryogenesis on Nitsch and Nitsch-derived medium (9.1%) was higher than in Murashige and Skoog-derived medium (5.9%) and embryogenesis from ovaries (10.1%) was 2-fold higher than from anthers (4.9%). Earlier flower developmental stages (II–III) favored embryogenic induction from anthers, while later stages (III–V) did it from ovaries. Induction of embryogenic cultures was genotype dependent. Two years after the establishment of the embryogenic lines, an average of 48.0% of the pro-embryogenic masses were viable and suitable to initiate cell suspensions. Embryogenic cultures of four genotypes showed a high percentage of conversion from embryos to plants: Albariño (61.8%), Garnacha (48.8%), Tempanillo (71.0%) and Sultanina (69.0%). Moreover, cell suspensions were competent for transient transformation based on β-glucuronidase assay, as up to 6,387 blue spots per Petri plate after Biolistic bombardment were obtained. Here, we present the advantage of ovaries over anthers for the embryogenesis induction of several grapevine cultivars. This is the first report of embryogenesis from the cultivars Albariño, Verdejo and Muscat Hamburg as well as transient transformation of Albariño and Tempranillo.     

Development of SCAR markers linked to powdery mildew (<Emphasis Type="Italic">Uncinula necator</Emphasis>) resistance in grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L. and <Emphasis Type="Italic">Vitis</Emphasis> sp.)

Sequence-characterized amplified regions markers (SCARs) were developed from six randomly amplified polymorphic DNA (RAPD) markers linked to the major QTL region for powdery mildew (Uncinula necator) resistance in a test population derived from the cross of grapevine cultivars “Regent” (resistant) × “Lemberger”(susceptible). RAPD products were cloned and sequenced. Primer pairs with at least 21 nucleotides primer length were designed. All pairs were tested in the F1 progeny of “Regent” × “Lemberger”. The SCAR primers resulted in the amplification of specific bands of expected sizes and were tested in additional genetic resources of resistant and susceptible germplasm. All SCAR primer pairs resulted in the amplification of specific fragments. Two of the SCAR markers named ScORA7-760 and ScORN3-R produced amplification products predominantly in resistant individuals and were found to correlate to disease resistance. ScORA7-760, in particular, is suitable for marker-assisted selection for powdery mildew resistance and to facilitate pyramiding powdery mildew resistance genes from various sources.     

Evaluation of methods for celery (<Emphasis Type="Italic">Apium Graveolens</Emphasis> L.) transformation using <Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis> and the <Emphasis Type="Italic">bar</Emphasis> gene as selectable marker

Callus selection (CS) and the flamingo-bill explant (FB) methods were evaluated for efficacy in transformation for celery. Agrobacterium tumefaciens strains EHA105 and GV3101, each with the bar gene under the promoters NOS (pGPTV-BAR) or 35S (pDHB321.1), were used. Leaf explants were inoculated and co-cultivated for 2 d in the dark. Calluses emerged on the explants on callus medium (C), Murashige and Skoog (MS) medium + 2,4-Dichlorophenoxyacetic acid (2,4-D) (2.3 μM) + kinetin (2.8 μM) + timentin (300 mg·l⁻¹). Calluses 4- to 6-wk-old were selected for glufosinate (GS) resistance by a two step method. First, calluses were transferred to C medium + GS 0.35, 0.5, 1, 2, 5, or 10 mg·l⁻¹; calluses formed only with 0, 0.35 and 0.5 mg·l⁻¹ GS. All growing calluses from 0 and 0.35 mg·l⁻¹ and a few from 0.5 mg·l⁻¹, were divided and placed back on C + GS 0.35–0.5 mg·l⁻¹ for another 5–6 wk. Second, tolerant clones were again divided and placed on C + GS 1–50 mg·l⁻¹. When cultivar XP85 was inoculated with both strains, using pGPTVBAR, 19 glufosinate resistant (GR) callus clones were selected, but shoots regenerated only for strain EHA105 inoculations. When both of the strains (each with pDHB321.1) were inoculated on cv. XP166, 3 and 12 GR calluses occurred for EHA105 and GV3101, respectively. Using CS, a total of 34 GR callus clones were selected, and shoots were regenerated from over 50% of them on Gamborg B5 medium + 6-(γ, γ-dimethylallylamino) purine 2ip (4.9 μM) + naphthaleneacetic acid (NAA; 1.6 μM) and rooted on MS in 5–6 mo total time. Conversely, using FB with inoculation by GV3101/pDHB321.1 on cv. XP166 yielded putative transgenic celery plants confirmed by polymerase chain reaction (PCR) in just 6 wk. Transformation of the bar gene into celery was confirmed by PCR for 5 and 6 CS and FB lines, respectively. Southern blot analyses indicated 1–2 copies in CS lines and 1 copy in FB lines. Herbicide assays on whole plants with 100 and 300 mg·l⁻¹ glufosinate indicated a range of low to high tolerance for lines derived by both methods. The bar gene was found to be Mendelian inherited in one self-fertile CS derived line.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated genetic transformation of grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) with a novel stilbene synthase gene from Chinese wild <Emphasis Type="Italic">Vitis pseudoreticulata</Emphasis>

A novel stilbene synthase gene (STS), cloned from Chinese wild Vitis pseudoreticulata (W. T. Wang) and responsible for synthesis of the phytoalexin resveratrol in grapevine, was successfully transferred into V. vinifera L. cv. Thompson Seedless via Agrobacterium tumefaciens-mediated transformation. Using transformation procedures developed in the present study, 72% GFP-positive germinated embryos were produced with about 38% of transformed embryos regenerated into normal plantlets. Integration of the STS gene into the transgenic plants was verified by PCR and Southern blot analysis. Expression of the STS gene was detected by high performance liquid chromatography (HPLC), which showed that the resveratrol concentration in the transgenic plants was 5.5 times higher than that in non-transformed control plants. Chaohong Fan and Ni Pu contributed equally to this work.     

Pollen-mediated intraspecific gene flow from herbicide resistant oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

The cultivation of genetically modified (GM) herbicide resistant oilseed rape (Brassica napus) has increased over the past few years. The transfer of herbicide resistance genes via pollen (gene flow) from GM crops to non-GM crops is of relevance for the realisation of co-existence of different agricultural cultivation forms as well as for weed management. Therefore the likelihood of pollen-mediated gene flow has been investigated in numerous studies. Despite the difficulty to compare different experiments with varying levels of outcrossing, we performed a literature search for world-wide studies on cross-fertilisation in fully fertile oilseed rape. The occurrence and frequency of pollen-mediated intraspecific gene flow (outcrossing rate) can vary according to cultivar, experimental design, local topography and environmental conditions. The outcrossing rate from one field to another depends also on the size and arrangement of donor and recipient populations and on the ratio between donor and recipient plot size. The outcrossing levels specified in the presented studies are derived mostly from experiments where the recipient field is either surrounding the donor field (continuous design) or is located as a patch at different distances from the donor field (discontinuous design). Reports of gene flow in Brassica napus generally show that the amount of cross-fertilisation decreases as the distance from the pollen source increases. The evidence given in various studies reveals that the bulk of GM cross-fertilisation occurs within the first 10 m of the recipient field. The removal of the first 10 m of a non-transgenic field facing a GM crop might therefore be more efficient for reducing the total level of cross-fertilisation in a recipient sink population than to recommend separation distances. Future experiments should investigate cross-fertilisation with multiple adjacent donor fields at the landscape level under different spatial distributions of rapeseed cultivars and different cropping systems. The level of cross-fertilisation occurring over the whole field is mainly important for co-existence and has not been investigated in agricultural scale experiments until now. Potential problems with herbicide resistant oilseed rape volunteers arising from intraspecific gene flow can be largely solved by the choice of suitable cultivars and herbicides as well as by soil management.     

Regeneration and<Emphasis Type="Italic"> Agrobacterium-</Emphasis>mediated transformation of hop (<Emphasis Type="Italic">Humulus lupulus</Emphasis> L.)

An efficient procedure for direct organogenesis and regeneration of hop (Humulus lupulus L.) was established. For the first time Agrobacterium-mediated genetic transformation of hop (cv. "Tettnanger") was achieved. Shoot internodes from in vitro cultures were identified as the most suitable type of explant for regeneration. Using this type of explant, a shoot-inducing medium was developed that supported direct organogenesis of approximately 50% of the explants. Plantlets were successfully rooted and transferred to the greenhouse. Overall, in less than 6 months hop cultures propagated in vitro were regenerated to plants in the greenhouse. Agrobacterium-mediated genetic transformation was performed with the reporter gene GUS (-glucuronidase). The presence and function of transgenes in plants growing in the greenhouse was verified by PCR (polymerase chain reaction) and enzyme assay for GUS activity, respectively. We have obtained 21 transgenic plants from 1,440 explants initially transformed, yielding an overall transformation efficiency of 1.5%.Abbreviations BAP 6-Benzylaminopurine - GA₃ Gibberellic acid - GUS -Glucuronidase - IAA Indole-3-acetic acid - IBA Indole-3-butyric acid - NAA -Naphthaleneacetic acid - nptII Neomycin phosphotransferase II - PCR Polymerase chain reaction - TDZ 1-Phenyl-3-(1,2,3-thiadiazol-5-yl) urea (thidiazuron)Communicated by H. Lörz     

<Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-mediated creeping bentgrass (<Emphasis Type="Italic">Agrostis stolonifera</Emphasis> L.) transformation using phosphinothricin selection results in a high frequency of single-copy transgene integration

Genetic transformation of creeping bentgrass mediated by Agrobacterium tumefaciens has been achieved. Embryogenic callus initiated from seeds (cv. Penn-A-4) was infected with an A. tumefaciens strain (LBA4404) harboring a super-binary vector that contained an herbicide-resistant bar gene driven either by the CaMV 35S promoter or a rice ubiquitin promoter. Plants were regenerated from 219 independent transformation events. The overall stable transformation efficiency ranged from 18% to 45%. Southern blot and genetic analysis confirmed transgene integration in the creeping bentgrass genome and normal transmission and stable expression of the transgene in the T₁ generation. All independent transformation events carried one to three copies of the transgene, and a majority (60–65%) contained only a single copy of the foreign gene with no apparent rearrangements. We report here the successful use of Agrobacterium for the large-scale production of transgenic creeping bentgrass plants with a high frequency of a single-copy transgene insertion that exhibit stable inheritance patterns.Abbreviations 2,4-D: 2,4-Dichlorophenoxyacetic acid - bar: Bialaphos resistance gene - GUS: -Glucuronidase - PPT: Phosphinothricin - ubi: Ubiquitin Communicated by J.M. Widholm     

Gas exchange in the salt marsh species <Emphasis Type="Italic">Atriplex portulacoides</Emphasis> L. and <Emphasis Type="Italic">Limoniastrum monopetalum</Emphasis> L. in Southern Portugal

Salt marshes are ecosystems subjected to a variety of environmental stresses like high salinity, water deficit, intense radiation or high temperatures. Field measurements were conduced in two halophyte species, Atriplex portulacoides L. and Limoniastrum monopetalum L., in the Reserva Natural do Sapal de Castro Marim, to compare their physiological response, i.e., water potential (ψ), net photosynthetic rate (A), stomatal conductance (gs) under natural conditions. Both species demonstrated marked variations in ψ throughout the year, with very low values in the summer, the period of higher salinity, drought and temperature. Deficit water potential (Δψ = ψ_midday − ψ_predawn) was lower in the summer than in other seasons in A. portulacoides but not in L. monopetalum. The highest values for A and gs in L. monopetalum were observed in autumn and for A. portulacoides in winter, presenting both lowest values in spring and summer. A_max was particularly high for L. monopetalum than for A. portulacoides in summer and autumn, despite gs_max was similar in both species. Diurnal pattern of A and gs were similar in both species, with higher values in the morning, decreasing throughout the day.     

Long-term study of somatic embryogenesis from anthers and ovaries of 12 grapevine (<Emphasis Type="Italic">Vitis</Emphasis> sp.) genotypes

Summary Anthers and ovaries of six grapevine cultivars (three Vitis vinifera L., two V × Labruscana L. H. Bailey, and one complex hybrid) were extracted from flower buds over 2 yr and cultured on three media reported to promote somatic embryogenesis in Vitis tissues. The highest percent embryogenesis from the hybrid ‘Chancellor’ and V. vinifera ‘Chardonnay’, ‘Merlot’, and ‘Pinot Noir’ occurred on medium C [Nitsch and Nitsch, 1969, basal medium with 3.0% (w/v) sucrose, 0.01% (w/v) inositol. 0.3% (w/v) Phytagel, 2.5 μM 2.4-dichlorophenoxyacetic acid, 2.5μM β-naphthoxyacetic acid, 5.0μM N-(2-chloro-4-pyridyl)-N′-phenylurea, and 0.05% (w/v) glutamine]. Regardless of the media, the labrusca cultivars ‘Concord’ and ‘Niagara’ produced soft non-embryogenic callus that was sometimes mixed with well-developed somatic embryos. Nine vinifera genotypes were further tested for several different years on medium C. Embryogenic cultures suitable for transformation were obtained from all genotypes in more than 1 yr. The average percent embryogenesis from ovaries was 7-fold higher than from anthers. There was significant annual variation in percent embryogenesis, demonstrating the need for media comparisons to be replicated for more than one season. Suspension cultures suitable for use in genetic transformation were initiated from ‘Chardonnay’, ‘Merlot,’ and ‘Pinot Noir’ pro-embryogenic masses. ‘Chardonnay’ suspension cultures plated and grown under conditions developed for recovery of plants after biolistic transformation yielded approximately 500 non-transformed embryos per plate after 4 mo. of culture, with 68.6% of the embryos converting to plants. This is the first reported protocol for embryogenesis from ‘Concord,’ ‘Cabernet Franc,’ and ‘Pinot Noir’ grapevines.     

Identification of SNPs and development of functional markers for LMW-GS genes at <Emphasis Type="Italic">Glu-D3</Emphasis> and <Emphasis Type="Italic">Glu-B3</Emphasis> loci in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Low-molecular-weight glutenin subunits (LMW-GS) have great effect on wheat processing quality, but were numerous and difficult to dissect by SDS-PAGE. The development of functional markers may be the most effective way for a clear discrimination of different LMW-GS genes. In the present study, three different approaches were used to identify SNPs of different genes at Glu-D3 and Glu-B3 loci in bread wheat for the development of six STS markers (3 for Glu-D3 and 3 for Glu-B3 genes) that were validated with distinguished wheat cultivars. Firstly, seven LMW-GS gene sequences ( AY585350, AY585354, AY585355, AY585356, AY585349, AY585351 and AY585353 ) from Aegilops tauschii, the diploid donor of the D-genome of bread wheat, were chosen to design seven pairs of AS-PCR primers for Glu-D3 genes. By amplifying the corresponding genes from five bread wheat cultivars with different Glu-D3 alleles (a, b, c, d and e) and Ae. tauschii, a primer set, S13F2/S13R1, specific to the gene AY585356, was found to be positive to cultivars with alleles Glu-D3c and d. Nevertheless, the other five pairs of primers designed from AY585350, AY585349, AY585353, AY585354 and AY585355, respectively, did not produce specific PCR products to the cultivars tested. Secondly, all the PCR products from the five primer sets without specific characteristics were sequenced and an SNP from the gene AY585350 was detected in the cultivar Hartog, which resulted in the second STS marker S1F1/S1R3 specific to the allelic variant of AY585350. Thirdly, three Glu-D3 sequences (AB062851, AB062865 and AB062872) and three Glu-B3 sequences (AB062852, AB062853 and AB062860) defined by Ikeda et al. (2002) were chosen to query wheat EST and NR databases, and DNA markers were developed based on the putative SNPs among the sequences. Using this approach, four STS markers were developed and validated with 16-19 bread wheat cultivars. The primer set T1F4/T1R1 was also a Glu-D3 gene-specific marker for AB062872, while T2F2/T2R2, T5F3/T5R1 and T13F4/T13R3 were all Glu-B3 gene specific markers for AB062852, BF293671 and AY831800, respectively. The chromosomal locations of the six markers were verified by amplifying the genomic DNA of Ae. tauschii (DD), T. monococcum (AA) and T. turgidum (AABB) entries, as well as Chinese Spring and its group 1 chromosome nulli-tetrasomic lines. The results are useful to discriminate the corresponding Glu-D3 and Glu-B3 genes in wheat breeding programs.     

Abscisic Acid Sprays Significantly Increase Yield per Plant in Vineyard-Grown Wine Grape (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) cv. Cabernet Sauvignon Through Increased Berry Set with No Negative Effects on Anthocyanin Content and Total Polyphenol Index of Both Juice and Wine

In many cultivars of Vitis vinifera periods of mild water stress during ripening are thought to increase grape quality for winemaking, even though yields may be negatively affected. Because abscisic acid (ABA) is involved in the signaling of water stress in plants, we examine the effects of the ABA signal being given without the concomitant water stress. ABA at 250 mg l⁻¹ was sprayed weekly or biweekly from bud-burst until harvest onto the leaves of vineyard-grown plants of cv. Cabernet Sauvignon. For ABA-treated plants berry yield per bunch and per plant was significantly increased (1.5- to 2.0-fold) across three consecutive harvests (2005 through 2007). Number of berries per bunch and per plant was the primary basis for the significant crop increases, although bunches per plant also tended to increase (1.1- to 1.3-fold) across all three harvests. Other parameters assessed included number of internodes, shoot length, leaf area, leaf water potential at midday, photosynthesis, and stomatal conductance. These parameters showed no significant change with ABA treatment, although shoot length tended to be reduced, as was leaf area relative to control plants. The significantly increased fruit yields were thus accomplished without accompanying increases in leaf photosynthesis and leaf areas. Juice at harvest had equal levels of sugars (Brix) and somewhat higher levels of anthocyanins and total polyphenols relative to control values. The two latter trends continued for the resultant wine across two vintage years. In conclusion, three seasons of experimental trials have demonstrated that ABA application can significantly enhance yield per plant in the field-grown grape (cv. Cabernet Sauvignon) by favoring increased berry set without diminishing the quality of the fruit for winemaking use.