THE EVOLUTION OF GRAPES RIPENING DURING GROWING SEASON 2021 IN DRĂGĂȘANI VINEYARD

Harvesting grapes at optimum maturity is an essential condition for obtaining wines of the desired quality. The ripening of the grapes is a dynamic process, that is why the physico-chemical parameters followed for the evaluation of the quantity and quality of the harvest are constantly changing both in terms of their values and the relationships between them. Harvesting grapes at maturity corresponding to the type of wine to be obtained requires rigorous monitoring of the dynamics of maturation. In the Drăgășani vineyard, the local varieties, older or newer, enjoy a special appreciation. In order to be able to highlight its full qualitative potential, harvesting grapes at optimal maturity is the first condition, especially in the wine-growing years characterized by special climatic conditions, such as 2021

The study regarding the agrobiological and technological properties of some clonal elites for table grapes, under the conditions of the Murfatlar vineyard

At the Research and Development Station for Viticulture and Vinification Murfatlar, in the period 2019 – 2022, was carried out clonal selection work on two cultivars for table grapes, respectively: 'Victoria' and 'Coarnă neagră'. The research consisted of the comparative study of five clonal elites of each cultivar, regarding their agrobiological and technological qualities, correlated with the specific climatic conditions of the Murfatlar vineyard. The five elites of each cultivar were studied and analyzed compared to the characters of the initial cultivar (the control). In the case of the 'Victoria' cultivar, out of the five elites under study, the one that stands out is the clonal elite ‘Victoria 57/4/7', which has great vigor, good fertility 63-73%, and high productivity. The preservability of grapes on the bush is long, about 30 days. Grape production is high, over 16-18 t/ha, of which 83-85% is commodity production. When are ripe for consumption, the grapes accumulate 140-150 g/l sugars, and the acidity is relatively low 3.8-4 g/l H2SO4. Regarding the cultivar 'Coarnă neagră', of the five elites under study, the one that stands out is the clonal elite 'Coarnă neagră’ 14/5/22', which has great vigor, high fertility, and medium ripening. The grape is large, cylindrical or cylindrical-conical in shape. Grape production is high, 20-25 t/ha, of which 85% is commodity production. The preservability on the bush is high, between 25-30 days. When are ripe for consumption, grapes accumulate 170–180 g/l sugars, and 5 g/l H2SO4 total acidity

Building nonparametric nn-body force fields using Gaussian process regression

Constructing a classical potential suited to simulate a given atomic system is a remarkably difficult task. This chapter presents a framework under which this problem can be tackled, based on the Bayesian construction of nonparametric force fields of a given order using Gaussian process (GP) priors. The formalism of GP regression is first reviewed, particularly in relation to its application in learning local atomic energies and forces. For accurate regression it is fundamental to incorporate prior knowledge into the GP kernel function. To this end, this chapter details how properties of smoothness, invariance and interaction order of a force field can be encoded into corresponding kernel properties. A range of kernels is then proposed, possessing all the required properties and an adjustable parameter $n$ governing the interaction order modelled. The order $n$ best suited to describe a given system can be found automatically within the Bayesian framework by maximisation of the marginal likelihood. The procedure is first tested on a toy model of known interaction and later applied to two real materials described at the DFT level of accuracy. The models automatically selected for the two materials were found to be in agreement with physical intuition. More in general, it was found that lower order (simpler) models should be chosen when the data are not sufficient to resolve more complex interactions. Low $n$ GPs can be further sped up by orders of magnitude by constructing the corresponding tabulated force field, here named "MFF".Comment: 31 pages, 11 figures, book chapte

Molecular characterization of old local grapevine varieties from South East European countries

South East European (SEE) viticulture partially relies on native grapevine varieties, previously scarcely described. In order to characterize old local grapevine varieties and assess the level of synonymy and genetic diversity from SEE countries, we described and genotyped 122 accessions from Albania, Federation of Bosnia and Herzegovina (B&H), Croatia, Macedonia, Moldova, Montenegro, Republika Srpska (Bosnia and Herzegovina) and Romania on nine most commonly used microsatellite loci. As a result of the study a total of 86 different genotypes were identified. All loci were very polymorphic and a total of 96 alleles were detected, ranging from 8 to 14 alleles per locus, with an average allele number of 10.67. Overall observed heterozygosity was 0.759 and slightly lower than expected (0.789) while gene diversity per locus varied between 0.600 (VVMD27) and 0.906 (VVMD28). Eleven cases of synonymy and three of homonymy have been recorded for samples harvested from different countries. Cultivars with identical genotypes were mostly detected between neighboring countries. No clear differentiation between countries was detected although several specific alleles were detected. The integration of the obtained genetic data with ampelographic ones is very important for accurate identification of the SEE cultivars and provides a significant tool in cultivar preservation and utilization.

Understanding high pressure hydrogen with a hierarchical machine-learned potential

The hydrogen phase diagram has a number of unusual features which are generally well reproduced by density functional calculations. Unfortunately, these calculations fail to provide good physical insights into why those features occur. In this paper, we parameterize a model potential for molecular hydrogen which permits long and large simulations. The model shows excellent reproduction of the phase diagram, including the broken-symmetry Phase II, an efficiently-packed phase III and the maximum in the melt curve. It also gives an excellent reproduction of the vibrational frequencies, including the maximum in the vibrational frequency $\nu(P)$ and negative thermal expansion. By detailed study of lengthy molecular dynamics, we give intuitive explanations for observed and calculated properties. All solid structures approximate to hexagonal close packed, with symmetry broken by molecular orientation. At high pressure, Phase I shows significant short-ranged correlations between molecular orientations. The turnover in Raman frequency is due to increased coupling between neighboring molecules, rather than weakening of the bond. The liquid is denser than the close-packed solid because, at molecular separations below 2.3\AA, the favoured relative orientation switches from quadrupole-energy-minimising to steric-repulsion-minimising. The latter allows molecules to get closer together, without atoms getting closer but this cannot be achieved within the constraints of a close-packed layer

Mulching Effect on Quantitative and Qualitative Characteristics of Yield in Sweet Potatoes

Sweet potatoes have multiple uses as food, feed, and in industrial production. They are characterized by their need for high temperatures for optimal development. This study aimed to analyze the quantitative and qualitative aspects of growing sweet potato cultivars in southwest Romania using mulching and non-mulching systems. The effects of mulching on the production of tuberous roots and the contents of total soluble substance, vitamin C, starch, total polyphenols, and antioxidant activity (DPPH) were evaluated in three cultivars with white pulp (the ‘Pumpkin’ and ‘Chestnut’ cultivars) and with orange pulp (the ‘Italian’ cultivar). It was found that mulching with polyethylene film improved the production of sweet potatoes, amounting to 41.42 t/ha in the case of the ‘Italian’ cultivar. Moreover, the effect of mulch induced increases in total soluble substance (16.40%) and starch (16.01%) in the ‘Chestnut’ cultivar, in vitamin C (9.23 mg/100 g d.w.) in the ‘Pumpkin’ cultivar, and in antioxidant activity in the ‘Pumpkin’ (2716.55 µmol AsA/g d.w.) and ‘Chestnut’ cultivars (1131.31 µmol AsA/g d.w.), while the polyphenols in the ‘Italian’ cultivar decreased. © 2022 by the authors. Licensee MDPI, Basel, Switzerland