Showing papers in "Vitis: Journal of Grapevine Research in 2001"

Influence of water deficits on grape berry growth

Abstract: The effects of early and late water deficits on pericarp cell division and enlargement of Syrah berries ( Vitis vinifera L.) was determined by DNA extraction and quantification. Different periods and different levels of water deficit were applied between anthesis and maturity to grapevines growing under controlled water supply in two consecutive years. DNA extraction profiles showed that water deficit did not affect cell division. Reduction of berry size and berry weight was caused exclusively by a decrease of pericarp volume, independent of the intensity of the water deficit or the stage of berry development. Decreased cell volume as a result of an early water deficit from flowering to veraison was irreversible. These results support the hypothesis that early water deficits modify the structural properties of the cell components and consequently cell wall extensibility, thereby limiting the subsequent enlargement of pericarp cells.

The Muscats: A molecular analysis of synonyms, homonyms and genetic relationships within a large family of grapevine cultivars

Abstract: The Muscats are a large, wide-spread family of grapevines, having in common besides the name the typical Muscat flavour. A huge number of synonyms and homonyms makes it difficult to identify them. Sixty-four accessions were analysed in the present work; they are representatives of the huge variability of this family as far as morphological aspects, berry colour and size, time of ripening and aptitude for wine and/or table grape production are considered. An analysis was performed at two isozymes and 25 microsatellite loci. The 64 accessions were reduced to 20, which were easily distinguishable from each other at the molecular level by as few as two microsatellite loci, The remaining 44 were found to be synonyms. Three mutants with red and pink coloured berries were identified in the Moscato bianco group. Moscato nero encompasses at least two, Moscato rosa three different varieties. It seems that only two of the analysed Muscats are the main progenitors of the Muscat family: Moscato bianco and Muscat of Alexandria, which in turn are joined by a direct parent-offspring link. We were unable to discriminate biotypes belonging to the same cultivar by microsatellite markers.

Grapevine microsatellite repeats: Isolation, characterisation and use for genotyping of grape germplasm from Southern Italy

Abstract: New microsatellite repeat markers from Vitis vinifera L. are described. Of the designed primer pairs, 7 were able to amplify homologous loci in 5 genetically diverse Vitis genotypes. The 7 markers developed in this study and 6 additional ones were used to fingerprint grapevine germplasm from southern Italy. Microsatellite analysis allowed almost all the analysed genotypes to be differentiated and uncovered two mislabeled cultivars (Castiglione and Marsigliana nera). No clonal differences were detected. Genetic relationships between the Italian cultivars were also investigated and a considerable degree of similarity was found.

Analysis of red wine phenolics: Comparison of HPLC and spectrophotometric methods

Abstract: A recently developed ion-pair normal phase HPLC method which allows a precise chromatographic evaluation of the whole class of high-molecular-mass phenolics of wine was used in order to check the performance of spectrophotometric methods. Thirty-two monovarietal red wines (vintages 1993 and 1998) were analysed for total high-molecular-mass phenolics, proanthocyanidins with 2-4 units, and proanthocyanidins formed by 5 or more units, by means of the normal phase HPLC method. In addition the following spectrophotometric assays were performed: total phenols by Folin-Ciocalteu, Bate-Smith transformation of proanthocyanidins into cyanidin and catechins and proanthocyanidins reactive to vanillin.

Improved control of water loss from micropropagated grapevines ( Vitis vinifera cv. Nebbiolo)

Abstract: Micropropagated plantlets are generally susceptible to rapid desiccation when exposed to reduced relative humidity and require a costly acclimatization procedure. Detached leaves of micropropagated Vitis vinifera , cv. Nebbiolo, plantlets were used to evaluate the relative contribution of leaf cuticle and stomata to water loss. Water loss occurred mainly from the abaxial surface of detached leaves; moreover, a large majority of stomata was still open 3 h after exposure to 63 % RH. An indirect estimation of epicuticular wax suggested a lower wax deposition for micropropagated plantlets compared to acclimatized and field-grown plants of the same clone. A previously developed method to produce hardened micropropagated plants was adopted: 1 mg(.)l(-1) paclobutrazol (PBZ) was added to the medium and culture vessels with reduced relative humidity (rRH) were used during the last stage of micropropagation. Under our experimental conditions, rRH was more effective to reduce transpiration than PBZ; a combination of both treatments improved plant survival during acclimatization.

Discrimination of wild grapes native to China by RAPD markers

Abstract: A set of 73 types of 18 wild grape species native to China, one interspecific hybrid, 7 Vitis vinifera cultivars, the rootstock cultivar SO 4 and one V. riparia accession were investigated using the RAPD technique. The screening of 280 decamer oligonucleotides allowed the selection of 20 primers used for the analysis. RAPD fingerprints of 83 grape samples were obtained. 191 bands, intense and easy to score, were chosen as markers. On average 5.7 bands per primer were amplified with an average of 68.7 % polymorphism. The size of amplified bands ranged from 100 to 3000 bp. Discrimination of 83 samples was obtained with one of two primers (OPQ04, OPJ07) combined with one of 5 primers (OPJ01, OPH19, OPP02, OPA15, OPU16). The average number of bands for each sample per primer was 5.7. This revealed a high level of polymorphism among the wild grapes native to China. RAPD markers proved to be useful for identification as they are quick and easy to use.