Peter R. Clingeleffer

Contrast in chloride exclusion between two grapevine genotypes and its variation in their hybrid progeny

Potted grapevines of 140 Ruggeri (Vitis berlandieri × Vitis rupestris), a good Cl− excluder, and K 51-40 (Vitis champinii × Vitis riparia ‘Gloire’), a poor Cl− excluder, and of a family obtained by crossing the two genotypes, were used to examine the inheritance of Cl− exclusion. Rooted leaves were then used to further investigate the mechanism for Cl− exclusion in 140 Ruggeri. In both a potting mix trial (plants watered with 50 mM Cl−) and a solution culture trial (plants grown in 25 mM Cl−), the variation in Cl− accumulation was continuous, indicating multiple rather than single gene control for Cl− exclusion between hybrids within the family. Upper limits of 42% and 35% of the phenotypic variation in Cl− concentration could be attributed to heritable sources in the potting mix and solution culture trials, respectively. Chloride transport in roots of rooted leaves of both genotypes appeared to be via the symplastic pathway, since addition of 8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS), an apoplastic tracer, revealed no obvious PTS fluorescence in the laminae of either genotype, despite significant accumulation of Cl− in laminae of K 51-40 during the PTS uptake period. There was no significant difference in either unidirectional 36Cl− flux (10 min) or 36Cl− uptake (3 h) into roots of rooted leaves exposed to 5, 10, or 25 mM Cl−. However, the percentage of 36Cl− transported to the lamina (3 h) was significantly lower in 140 Ruggeri than in K 51-40, supporting reduced Cl− loading into xylem and implicating the root stele in the Cl− exclusion mechanism.

Improved in ovulo embryo culture for stenospermocarpic grapes (Vitis vinifera L.)

In ovulo embryo rescue techniques have been used to recover new hybrids from seedless × seedless grape crosses. This study was conducted to increase efficiency by investigating effects of genotype, medium, and ovule removal age on ovule elongation, embryo recovery, growth, and plantlet formation. Ovules from self-pollinated berries of seedless varieties Sunmuscat, Merbein Seedless, and Marroo Seedless were cultured at 30, 43, 60, and 70 days after flowering (DAF) in a range of media, some of which were supplemented with gibberellic acid (GA3) and indole-3-acetic acid (IAA). The effect of activated charcoal (AC) in media on rescued embryos was also investigated. Ovules exhibited continuous growth in vivo and in vitro. The most vigorous growth was observed for ovules cultured at 30 and 43 DAF, but more embryos were recovered from ovules cultured at 60 and 70 DAF. Ovule growth and embryo production in vitro were improved in Bouquet and Davis (BD) and Nitsch and Nitsch (NN) media. Supplementation with GA3 increased embryo recovery rates. Highest embryo recovery rates were 18.1%, 9.6%, and 12.2% for Sunmuscat, Merbein Seedless, and Marroo Seedless, respectively, when ovules were excised and cultured at 60 or 70 DAF in either BD or NN media. In vitro embryo survival and plantlet formation were higher for torpedo-shaped embryos, and improved greatly in 6-benzyladenine (BA)-supplemented woody plant (WP) medium containing 0.3% AC. Embryo recovery was improved by excising and culturing ovules at 60 DAF in BD or NN media and then by transferring embryos to WP medium supplemented with BA and AC.

Management practices impact vine carbohydrate status to a greater extent than vine productivity

Light pruning and deficit irrigation regimes are practices which are widely used in high yielding commercial vineyards in the warm climate regions of Australia. Little information is available on their impacts on carbohydrate dynamics in vegetative organs within and between seasons, and on the resulting plant capacity to maintain productivity and ripen fruits. This study was conducted to address this gap in knowledge over five vintages on Vitis vinifera L. cv. Cabernet Franc, Shiraz, and Cabernet Sauvignon in the Sunraysia region of Victoria, Australia. Lighter pruning did not change the total carbohydrates concentration and composition in wood and roots within seasons in Cabernet Franc and Shiraz. However, the total carbohydrate pool (starch and soluble sugars) at the end of dormancy increased under lighter pruning, due to higher vine size, associated with retention and growth of old-wood (trunk and cordons). Water deficit negatively impacted trunk and leaf starch concentrations, over the day and within seasons in Cabernet Sauvignon. Soluble sugars concentrations in these tissues tended to be higher under limited water supply, possibly due to higher sugar mobilization as photosynthesis decreased. Trunk carbohydrate concentrations markedly varied within and between seasons, highlighting the importance of interactive factors such as crop load and climate on carbon status. The period between fruit-set and véraison was shown to be critical for its impact on the balance between carbon accretion and depletion, especially under water deficit. The lower leaf and trunk starch concentration under water deficit resulted in a decrease of yield components at harvest, while similar yields were reached for all pruning systems. The sugar allocated to berries at harvest remained remarkably stable for all practices and seasons, irrespective of vine yield and carbohydrate status in vegetative organs in Shiraz and Cabernet Sauvignon.

Micronutrient Mineral and Folate Content of Australian and Imported Dried Fruit Products

A selection of Australian and imported fresh and dried fruit products, including sultanas, Sunmuscats, Carina currants, Zante currants, apricots, and prunes, were analyzed for selected minerals (Ca, Mg, Na, S, B, Al, Fe, Mn, Cu, Zn, Mo, and Se), folate and vitamin C, and the capacity of dried fruits for dietary provision of these micronutrients evaluated. Micro-nutrients were concentrated by a factor of 3–5 in dried fruits compared with their fresh fruit counterparts and were consequently present in nutritionally significant levels, in contrast to fresh fruit. Australian dried sultanas, Carina currant, Zante currant, apricots, and prunes contained Cu, Fe, K, and Mn at levels of >20% of daily Required Dietary Intake (RDI, taken as the average for adult men and women as nominated by the Australian National Health and Medical Research Council) and Sunmuscats contained Cu, Fe, and K at >20% of RDI. All dried fruits studied contained boron in the range of 1.5 to 5.4 mg per 100 g; however, the RDI for boron has not been defined by the NHMRC at the present time. All sultanas and currants studied contained folate at levels of 10–20% of RDI per 100 g. Experimental drying methods significantly affected folate levels with higher folate content in non-ground versus ground-based drying methods. Of the micro-nutrients supplying >20% of RDI, folate represents a particular nutrient for which the mean daily intake of adult Australians is typically inadequate. This study shows that dried fruit consumption, in contrast with fresh fruit, can provide significant proportions of daily requirements of several micronutrients, particularly folate.

A Simple Microplate Assay to Quantify Nonstructural Carbohydrates of Grapevine Tissues

Knowledge of total nonstructural carbohydrates in plant material is useful for understanding the effects of environmental conditions and vineyard management decisions on grapevine physiology. While many techniques are described in the literature, varying in degree of sophistication, few have been validated in grapevines. We describe the miniaturization of a simple extraction method and microplate based colorimetric assay for the measurement of nonstructural carbohydrates in a range of grapevine tissues. The method provides quantitative results for soluble carbohydrates and starch in samples containing as low as 20 μg carbohydrate.

Heritability of adventitious rooting of grapevine dormant canes

One of the most important viticultural characteristics of a grapevine rootstock is the ability to form roots on dormant lignified canes (rootstrike). North American species of Vitis are the primary source of germplasm for grapevine rootstocks and vary widely in their rate of rootstrike. Breeders have hybridized grape species in order to introgress traits to produce commercial rootstocks. A combination of 26 parents consisting of improved and wild accessions of Vitis spp. was used to generate 27 families. The percentage of rootstrike of dormant canes was observed over several years for 552 individuals. A logistic generalized linear mixed model (GLMM) method was used to estimate the narrow sense heritability (h2) of rootstrike. Heritability was found to be moderate (h2 = 0.307 ± 0.050). The model also estimated breeding values of all parents and progeny. A GLMM method can be used to estimate breeding values of germplasm to identify individuals with commercially acceptable rates of rootstrike with a defined probability of transmitting this trait to progeny. This is useful for the introgression of traits into potentially new commercial rootstocks. The pattern of normal distribution of rooting indicates that it is possible to identify individuals with good rootstrike from Vitis species that are generally considered to have low rootstrike. Selection of individuals with a higher breeding value will increase the efficiency of rootstock breeding.

Pollen fertility and berry setting behaviour of the grape variety Carina

Carina is a significant grape variety grown in Australia to produce dried currants. Its yield and fruit quality are restricted by pollination; however, this can be improved by the judicious use of hormone-based setting sprays. Male fertility and seedless berry set in Carina were investigated by examining pollen viability, the effect of self- and cross-pollination on berry set and in ovulo embryo recovery in comparison with two pollen sterile varieties, Hunisa and Kishmishi. Carina pollen failed to germinate in vitro and gave poor berry set when used to pollinate Hunisa and Kishmishi. Percentage berry set in Carina was unaffected by pollination treatments, but cross-pollination increased berry size. Larger seed traces (>1.2 mm in length) were present in most cross-pollinated Carina berries and their size and number were correlated positively with berry size. In ovulo embryo recovery rates ranged from 19.7 to 49.0% and 6.8 to 13.6% for cross-pollinated combinations of Carina when ovules were cultured at 50 and 75 days after pollination, respectively. In contrast, embryo recovery was zero from self-pollinated ovules. The results indicated that Carina produces sterile or non-functional pollen and is capable of setting seedless fruits through either parthenocarpy and/or stenospermocarpy.

THE INFLUENCE OF GRAPE (VITIS VINIFERA L.) BERRY MATURITY ON DRIED FRUIT COLOUR

SummaryThe grape cvs Sultana H5 and Merbein Seedless produced light coloured dried fruit after treatment with an alkaline, oil-in water emulsion prior to drying. Berries were harvested at different times during the harvest period to give a range in soluble solids in the fresh fruit from 18 to 26 °Brix. The colour was evaluated by the CIE L*a*b* colour system. Low and high soluble solids concentrations in fresh fruit resulted in brown dried fruit. The lightest dried fruit was produced when the average soluble solids concentration in fresh fruit was between 21 and 22°Brix for ‘Merbein Seedless’ and 21 to 23°Brix for ‘Sultana H5’Sultana H5’ dried fruit was slightly lighter than that of ‘Merbein Seedless’. At the higher levels, positive linear relationships between lightness and soluble solids concentration became negative for both cultivars. The results, which describe a “narrow window of opportunity” for the production of light coloured dried fruit, indicate that the timing of harvest is critical for qualit...

Grapevine rootstocks resistant to the root-knot nematode Meloidogyne javanica

Background and Aims Root-knot nematodes (Meloidogyne spp.) are endo-parasites of plant roots and parasitisation can lead to diminished grape yields. Worldwide viticulture production is impacted primarily by four species of root-knot nematode (Meloidogyne arenaria, Meloidogyne hapla, Meloidogyne incognita and Meloidogyne javanica). Meloidogyne javanica is the predominant root-knot nematode found in Australian vineyards. A glasshouse-based experiment was conducted to identify grapevine cultivars and accessions with complete resistance (i.e. no reproduction of nematode) to an aggressive pathotype of M. javanica isolated from an Australian vineyard. Methods and Results Single-grapevine plants were inoculated with approximately 1500 second stage juveniles of M. javanica in a replicated study. Six weeks after inoculation, roots were washed free of soil, and egg masses were stained and tallied. The final dry mass of roots was measured to determine the ratio of egg masses to root mass. Conclusions Complete resistance to M. javanica was found in 42 of 75 Vitis cultivars and accessions screened. Significance of Study The M. javanica resistant cultivars and accessions identified in this study provide valuable material for future breeding in order to develop new rootstocks for the Australian wine and grape industry with durable resistance to root-knot nematode.

SNP markers tightly linked to root knot nematode resistance in grapevine (Vitis cinerea) identified by a genotyping-by-sequencing approach followed by Sequenom MassARRAY validation.

Plant parasitic nematodes, including root knot nematode Meloidogyne species, cause extensive damage to agriculture and horticultural crops. As Vitis vinifera cultivars are susceptible to root knot nematode parasitism, rootstocks resistant to these soil pests provide a sustainable approach to maintain grapevine production. Currently, most of the commercially available root knot nematode resistant rootstocks are highly vigorous and take up excess potassium, which reduces wine quality. As a result, there is a pressing need to breed new root knot nematode resistant rootstocks, which have no impact on wine quality. To develop molecular markers that predict root knot nematode resistance for marker assisted breeding, a genetic approach was employed to identify a root knot nematode resistance locus in grapevine. To this end, a Meloidogyne javanica resistant Vitis cinerea accession was crossed to a susceptible Vitis vinifera cultivar Riesling and results from screening the F1 individuals support a model that root knot nematode resistance, is conferred by a single dominant allele, referred as MELOIDOGYNE JAVANICA RESISTANCE1 (MJR1). Further, MJR1 resistance appears to be mediated by a hypersensitive response that occurs in the root apical meristem. Single nucleotide polymorphisms (SNPs) were identified using genotyping-by-sequencing and results from association and genetic mapping identified the MJR1 locus, which is located on chromosome 18 in the Vitis cinerea accession. Validation of the SNPs linked to the MJR1 locus using a Sequenom MassARRAY platform found that only 50% could be validated. The validated SNPs that flank and co-segregate with the MJR1 locus can be used for marker-assisted selection for Meloidogyne javanica resistance in grapevine.