Agronomic characterization variety Quebranta in the Ica region, Peru

Abstract

The study was to identify the best strains of the Quebranta variety cultivated in Peruvian region of Ica during campaigns 2011 to 2014. The evaluations were conducted in fourteen vineyards and the criteria to evaluate each one of them was that the same owner vineyard, would identify the best strain Quebranta for their good performance and sanitary quality. Productive parameters as grape weight and number of bunches per vine, average cluster weight, length and width of cluster and Berry weight were evaluated. Within the parameters of vegetative growth was assessed Ravaz index and as parameter for the composition of the grape was evaluated the concentration soluble solids (°Brix), total acidity and pH. Four phenological stages were recorded and defined from observed events in the branch of the year: Phase I comprising bud of winter to sprouting; Phase II of sprouting to full bloom; Phase III of full bloom to veraison and Phase IV of veraison to maturity. At the time of fruit setting were taken leaf samples to assess the State of health of each strain to Grapevine fanleaf virus, Grapevine fleck virus, Grapevine leafroll virus 1, Grapevine leafroll virus 3 and Tomato ringspot virus. The variables average bunch weight (22%), berry weight (20%), bunch length (13%) and bunch width (11%) presented the lowest values coefficient of variation. The variables of weight of grape per vine (52%), number of bunch (42%) and index of Ravaz (60%) has the highest values of coefficient of variation. Four variables were used that showed lower values (25%) coefficient of variation for the weighted average. The variables that presented perfect correlation were berry weight and width of bunch, berry weight and Ravaz index, length of bunch and Ravaz index. The analysis of conglomerate allowed to group the strains in study in two groups which showed a significant difference between them (p < 0.0001). The principal component analysis identified that the variable of weight per bunch, index Ravaz and berry weight distinguished the 77 strains studied. Soluble solids, acidity and pH of the grapes from the fourteen vineyards present significant difference. The phenology of the 77 study strains does not present significant difference. Samples of tender leaves were used for virus scanning. Only the variables of length and width of bunch showed a coefficient of variation acceptable accuracy. The weighted average analysis allowed choosing the best strains which are: QT1; QT5; QCH2; QCH3; QYJ1; QT2; QT3; QYJ4; QT4; QCH1 which will serve as base material for future certifications and improvement of this variety. The variables such as the number of bunch and bunch width feature the highest perfect correlation (0.89%). The grape presented in average 24.67 °Brix, acidity 4.14 g/L tartaric acid and 3.92 of pH. The phenological period total average of the 77 strains was 202 days and shows no significant difference. The results of the analysis of virus were negative for the 77 strains and for the five viruses that were analyzed.