Browsing by Subject "Grapevine"

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Lockerbeerigkeit bei Klonen von Spätburgunder (Pinot noir) : Analyse von molekularen Markern und der Einfluss von Gibberellin auf die Traubenmorphologie
(2014) Hoffmann, Petra; Blaich, Rolf
In viticulture, the architecture of the grape cluster affects the quality of the grapes. Compact grape clusters are more prone to B. cinerea infection, which reduces yield (Vail et al. 1998, Vail et al. 1991). Loose clusters have longer pedicel and rachis structures (Alleweldt 1959) and are less susceptible to B. cinerea. For this reason, the cultivation of clones with the loose cluster trait is of great interest. Loose clusters can result from the application of phytohormones, the spacing of the flower clusters, the thinning of fruit, or a reduced pruning. These treatments reduce berry set and promote pedicle elongation when applied to clones with compact clusters (Alleweldt 1959). Genetically based loose clustered grape phenotypes occur among grapevine cultivars. In this study we are able to differentitate between losse and compact clones using the marker FlExp2 on the basis of sequence data. The loose cluster clones show a 4 bp deletion at 219-222 bp and a C/T transition at 231 bp, unlike the compact cluster clones. In all tested Pinot ssp. clones, the sequence correlated to the phenotype. The marker was tested on other varieties such as Riesling, Gewurztraminer, Chardonnay, Chenin blanc, Cardinal and White Chasselas. The phenotypes were again consistent with the sequence. In the case of loose clustered table grapes, a deletion occurs instead of the transition at 231 bp. Additionally, the variety White Gutedel demonst- rated a C/T transition at 217 bp. These results were confirmed by sequencing 30 clo- nes (loose and compact clusters) in two repetitions in both directions. Both markers shwoed two fragments with a four bp difference. The amplification products are a In- del/SNP mutation for loose cluster and a „CTTT“ mutation for copmact cluster grapes.The CAPS and the SCAR marker identified that the trait of bunch architecture is heterozygous. The sequence of the amplification products was distinct for loose and compact cluster types. The SCAR marker shows two amplification products at 162 bp and 166 bp and the CAPS marker at 283 bp and 287 bp. The heterozygosity didn ́t produce a molecular marker for the MAS. In silico, analysis shows that the identified locus is in the Exon in the Vlexp1 gene. This gene is an expansin gene which is responsible for cell elongation (McQueen- Mason 1992). A part of the role which the hormones play in grape Morphology was analyzed in this study. The inflorescences of the genetically loose clustered clone 1-84 Gm did not show increased gibberellin concentration, indicating that gibberellin does not have a influence on the genetic based loose clone (1-84 Gm). However, the auxin concentra- tion in inflorescences of loose cluster clones increases earlier and remains high lon- ger than in those of the compact cluster clone 18 Gm. After a treatment with gib- berellin, the clone 1-84 Gm exhibited increased concentration of both gibberellin and auxin and formed even looser clusters. Similarly, the same treatment applied to the compact clone 18 Gm resulted in looser clusters and increased concentration of gib- berellin and auxin with a higher concentration of auxin for a longer period of time. It remains unclear precisely how the gibberellin treatment induces looser clusters. It may be that there is an interaction between gibberellin and auxin or that the auxin alone causes the cell extension. It remains an open question whether expansin toge- ther with gibberellin or auxin is responsible for the development of loose clusters, or if it is caused by a gibberellin auxin interaction. The growth pattern of the stalks and inflorescences were identified in order to put these results in context with the results of the hormone and genetic analysis. The stalks and inflorescences of the treated and untreated clones were measured weekly before GA3-application and continued four weeks after application. The growth of the flower clusters ended three weeks af- ter anthesis while the stalks grew continuously. In the loose cluster clone 1-84 Gm, the growth of stalks and flower clusters was significantly larger than in the compact cluster clone 18 Gm. The growth behavior of the peclone 18 Gm when treated with gibberellin was identical to the clone 1-84 Gm without gibberellin treatment. Gib- berellin treatment caused a significant increase in the growth of the stalk and flower clusters. The treated loose cluster clones formed the largest stalks while the untrea- ted compact cluster clone 18 Gm the smallest. Such clone growth behavior results in loose cluster architecture.
Mechanisms of frost adaptation and freeze damage in grapevine buds
(2002) Badulescu Valle, Radu Virgil; Blaich, Rolf
Mechanisms of frost hardening in compound (latent) buds of the grapevine cultivar ?Bacchus? were tested with different methods during three winters. The investigated parameters were LTE/HTE (low temperature exotherm/high temperature exotherm), water content, starch, sugar- and anions combination and bud histology. Water content from wood and buds was determined regularly every 2 weeks from March 1998 until Mai 2000. The lowest water content in wood and buds (about 40 %) was found between November and February. In general shoot sections and buds from the apical shoot area contained less water than in the basal area. Sugars and anions were analyzed with HPLC. The highest concentrations of soluble sugars were found in basal buds of the shoot, the lowest concentration in buds of the apical shoot area. Sucrose was the predominant soluble sugar, it was accompanied by glucose, fructose, sucrose, raffinose, and also stacchyose which was hitherto not described for grapevine buds. The concentration of soluble sugars increased during autumn and reached its maximum (around 150 mg/g dry matter) in November/December until the beginning of January then it decreased again to around 30 mg/g at bud burst. The predominant anion was sulphate while chloride could be detected only in traces. The anions reached their maximum at the beginning of January and in mid April. To evaluate the exotherm measuring method, model experiments were carried out with water drops (1µl) on filter paper and with small plant parts (leaf, stems, flower parts). Both the plant parts and the destilled water on the cellulose fiber freeze mainly between ?8 and ?15°C (an influence of the low osmotic value of the plant sap could not be found). After the first freezing the specimen were thawed and freezing repeated. The freezing points of the first and the second freezing cycle were significantly correlated. This shows that freezing does not occur at random, but is determined by ice nucleation sites characteristic for each sample. These sites even survive the physical destruction of the cells by the ice cristals. Further model experiments were carried out to get indications on possible barriers to ice cristal growth in plant tissue. Exotherm analysis was used to determine the freezing point of grapevine buds which is accompanied by a transient temperature rise called exotherm. The grapevine buds show 2 or more exotherms, one or two HTEs (high temperature exotherms) between ? 5 °C and ?10°C and the LTE (low temperature exotherm, sometimes more than one ) between ?10°C and ?25°C depending on the frost adaption of the buds. The HTEs are assumed to indicate the freezing of surface water or apoplastic water in the subtending tissue (bud pad), whereas the LTE (or LTEs) seem to be caused by freezing of the primary (and secondary) buds (shoot primordiy of the compound bud). The temperature minimum of the LTEs (down to ? 25 °C) is reached in January/February and is not influenced by humidity which, however, changes the THE values occuring usually around ? 10 ° and ? 4 °C, which are influenced by water in the bud scales. The LTEs of the buds in the lower area of the shoot were higher as compared to the buds in the middle and upper area of the shoot. The LTE analysis clearly shows the frost adaptation of the latent buds which usually reaches a maximum by the end of January but a clear relation to the changing air temperatures could not be established. Histological and cytological analyses were used to test for frost damage in bud parts and for changes during the cold adaptation. A modified staining method was developed to differentiate the cells. During automn and winter the buds contained a lot of starch grains which dissolved at bud burst. A permeability barrier between bud pad and shoot primordia could not be found, however it could be directly shown, that a HTE causes no cell damage in the buds, while after the appearence of the LTE(s) a disintegration of protoplasts in primary and secondary buds could be found. This is a direct evidence that LTEs indicates the death of the eyes in the complex grapevine bud. If after the appearance of the HTE the buds were held one day at this temperature before further cooling, no LTEs would appear. This and similar observations during the frost storage of grapevine cuttings is discussed in terms of the (harmless) ice formation in the bud base at moderate minus temperatures which would result in a freeze drying effect due to the lower water potential of the bud pad (in comparison to the non frozen eyes) and a further increase of the frost resistance of the growing points. If frost adapted grapevine shoots from the field were kept at 20°C deacclimation occurred after about 10 days. Accidentally wetted buds showed exotherms above ?4°C. In these buds and the watering water ice nucleating bacteria (Pseudomonas fluorescens) could be found.
Profiling of physiological responses and quality aspects in Vitis vinifera L. as influenced by aspects of N application
(2019) Lang, Carina Paola; Zörb, Christian
Viticulture and the vinification of vines (Vitis vinifera L.) to wine is an important branch in agriculture world-wide. Berry quality and the associated wine quality are the driving factors here. Nitrogen (N) is the most important plant nutrient for the grapevine. In addition to its influence on vegetative and generative growth, it determines significantly the metabolite composition and the oenological parameters of the grape berry. Nitrogen is present in various forms, such as nitrate, ammonium or amino acid, in the individual plant organs and is used differently by the grapevine. Grapevines are believed to have the ability to assimilate N in various forms, which in turn may affect the quality of berries and the resulting wine. For a better understanding of the effects of N on berry and wine quality, knowledge of which N-form can be assimilated by the vine and the way that this affects oenological parameters and quality-giving metabolites is essential. To this end, several investigations were carried out at various test levels, starting with hydroponic experiments, a pot experiment and a further field experiment, and on the matured wine. The various N-forms of nitrate, ammonium, urea and the amino acids arginine and glutamine were applied, following which the plant-physiological reactions of the grapevine and quality-determining parameters in berry and wine were measured. Furthermore, a metabolite profile with a focus on phenolic components was prepared and a sensory analysis of the wine was performed. The grapevines in the hydroponics and pot experiments were treated with 4 mM total N. The grapevines in the field experiment were fertilized with 60 kg N ha-1, calculated in relation to the block size. The rootstocks SO4 and RU140 showed similar patterns of N assimilation with respect to the N-form but differed significantly with regard to the level of growth and N content among all N-forms. The N-sensitive rootstock SO4 reacted more strongly than the rootstock RU140 and, therefore, SO4 was used for further experiments. This suggests that grapevines are able to assimilate the amino acids glutamine and arginine, as also shown by the enzymatic nitrate reductase activity and the increased abundance of the transcripts of nitrate reductase and nitrite reductase. Nevertheless, the N-forms NO3- and NH4+ were preferentially assimilated. The assimilation under urea treatment was significantly reduced. In addition to the N-form, the amount of N applied had an influence on N assimilation in the grapevine. With increasing amounts, the vegetative and generative growth increased up to a threshold. However, if this threshold was exceeded, both were significantly reduced. If the grapevine is overfertilized, the sink : source ratio changes, which will lead to a change in the biomass production and furthermore to a saturation and storage of N. In addition, competition for assimilates occurs, this alters the N distribution and N availability within the plant and the berries. The N-form has no influence on berry yield. The oenological and chemical parameters of the must and the wine are of enormous importance for product quality. The key components include pH and acidity, which contribute significantly to the organoleptic properties of wine. Both factors are influenced by the N-form and the amount of N offered. As the amount of N increases, the pH increases and the acidity decreases. The N-forms NO3- and urea and, the zero application (without additional N) show the highest influences. The must weight is a defining factor reflecting the berrys maturity and thus the time of harvest. As the amount of N increases, the must weight decreases. On the one hand, an increased N amount leads to lower acidity in the berry, indicating that more sugar is being stored and that the berry is in an advanced stage of maturity. On the other hand, an increased N amount leads to a decreasing must weight, which leads further to a maturation delay. The total phenolic content increases with increasing N amount, but is highest following zero N application. Tentative phenols measured in the metabolite profile are markedly down-regulated after urea treatment and are upregulated with NO3- following NH4+ treatment. This result might arise from reduced N assimilation in the root and thus reduced N availability for the berries. The influence of N on the aroma and sensory aspects of wine is controversial. The individual aroma attributes show both an increase and a decrease in their intensity attributable to N, mainly urea and NO3-. A marked influence between N-treated vines and the zero application is also apparent. However, these contrasting results clearly show that aroma and thus the sensory characteristics of wine can be influenced both positively and negatively. The results of the aroma and sensory evaluation in the agroforestry system underline once again the controversial influence of N on the sensory features of wine; no significant influence was measured. In summary, N has a significant influence on the vegetative and generative growth of the grapevine. The influence of N can be both positive and negative and is in part directly or indirectly linked to wine quality and should therefore not be ignored.
Untersuchungen zur Bedeutung und Lebensweise phytophager Thripse (Insecta, Thysanoptera) als Verursacher von Austriebsstörungen an Reben als Grundlage zur Entwicklung umweltschonender Bekämpfungskonzepte
(2006) Wipfler, Rosi; Zebitz, Claus P. W.
Aim of this study was to gain basic knowledge of the biology of thrips pest species on grapevine. The results should provide the basics to develop environmentally compatible protection strategies. From 2002 to 2004, a monitoring of thrips infested vineyards was done in the vine growing region Palatinate. Thrips population dynamics and level of infestation were investigated in different newly planted vineyards and nurseries, as well as the damage caused by thrips. To answer the question, how and where thrips hibernate in vineyards, different collection techniques were tested to detect thrips in the soil and underneath the bark of vines. During the vegetation period, the flight activity of thrips was monitored in different vineyards and nurseries. Thrips species of vineyards, surrounding crops and shrubberies were compared to reveal possible ways of infestation by thrips on grapevine. Different insecticides were tested to control adult thrips and larvae in the field. Considering the collected thrips species, most striking result was the dominant abundance of the onion thrips, Thrips tabaci Lindeman, which caused most of the damage. The expected grapvine thrips Drepanothrips reuteri Uzel was of minor importance. Preferences for different grapevine varieties could not be found. Infestation mainly appeared in nurseries and newly planted vineyards. 30 different thrips species could be detected on grapevine. The results on level of infestation and phenology corresponded mostly with the literature data on D. reuteri. In the investigated vineyards, infestation was only detected in spring. In three years of investigation, infestation rates decreased from the middle of June onwards. The reason was mainly a migration of the polyphagous T. tabaci to other host plants. The detailed description and documentation of thrips infestation symptoms resulted in additions to already known symptoms. It was also possible to make further differentiations to infestation symptoms not caused by thrips. During the investigations it could be proved that different thrips species overwinter underneath the bark of vines and in the soil of vineyards. Therefore, thrips can rapidly infest vines in the following spring. Field experiments with yellow water traps showed that airborne adult thrips and thrips that actively migrate from surrounding crops are of major importance for the infestation of grapevines. Nurseries showed an increased risk of infestation, because they are usually located outside the grapevine areas and are surrounded by other crops. In this study it was not possible to gain any hint that thrips are transferred by grafted vine cuttings. The influence of shrubberies on thrips species in vineyards was of minor importance but needs further studying. It would also be of interest to investigate the influence of different culture techniques on the level of infestation and the phenology of thrips in vineyards. The insecticidal compounds spinosad, abamectin and imidacloprid proved to be effective to control thrips in the field. For newly planted vineyards, two treatments are recommended in spring: first against adult thrips at the beginning of May, and the second against the hatched larvae 14 to 21 days later. Treatment is necessary at levels of infestation of more than one thrips per shoot at the grapevine developmental stage BBCH 09 to 13, and with more than one thrips per leave at BBCH 14 to 17, respectively. Preventive treatment is recommended 1. for newly planted nurseries, if there is an increased risk of infestation because of surrounding crops with detected thrips infestation, and 2. at the beginning of budding for newly planted vineyards and one year old vineyards, especially if there was thrips infestation in the previous year and if predatory mites are absent. Control experiments in the laboratory could not be done, because it was not possible to establish a thrips colony to supply enough thrips material. The results of this study contributed to the approval of the compounds imidacloprid and abamectin for minor uses to control thrips on grapevine in 2006.