​Ideal rootstock in peach cultivation

When producing stone fruit, such as peach, it is important to be aware of aspects such as the best graft/rootstock combination and the effects of soil and climate present in each growing region.

11.10.2016 | 20:59 (UTC -3)

Brazilian stone fruit production has different characteristics depending on the region. In Rio Grande do Sul, the cultivation of fruits for industry and dual purposes predominates, and in other regions, the planting of peaches, plums and nectarines for the table stands out. The main research actions with stone fruits involve creating and adapting cultivars that are resistant to diseases and produce quality fruit to consumer taste.

Rootstocks influence the degree of sensitivity to the environment, that is, the degree of climatic adaptation of the scion cultivar, as well as the different physiological responses to adverse conditions such as high temperatures during flowering, water deficit, irregular winter temperatures, thus affecting mode of formation of sexual gametes, varying the productive pattern of cultivars in the years of cultivation.

Therefore, it is important for producers to acquire information about the attributes and limitations of specific rootstocks and the effects of soil and climate in each region. To achieve this, studies on the performance of rootstocks are necessary for each specific soil and climate region, as with these evaluations it is possible to identify the best graft/rootstock combination ideal for obtaining quality fruit. Since the rootstock can influence the size and production of the grafted plants, as well as the quality.

The present work was carried out to evaluate the yield and quality components of Chimarrita and Maciel peach trees on different rootstocks in three cultivation locations and identify the dissimilarity between these rootstocks for the quality components, pointing out the variables with greater relative importance.

The experiment was conducted in three experimental fields: Embrapa Uva e Vinho, located in the municipality of Bento Gonçalves, in Rio Grande do Sul (site 1); Agricultural Experimental Station of the Federal University of Rio Grande do Sul, EEA/UFRGS (site 2), in Eldorado do Sul (RS); and Centro Agropecuário da Palma, CAP/UFPel (site 3), belonging to the Federal University of Pelotas, in the municipality of Capão do Leão (RS).

The canopy cultivars used were: Chimarrita (white pulp, consumption in natura) and Maciel (yellow pulp, dual purpose) on the rootstocks: 'Aldrighi' (Prunus Batsch L.), 'Capdeboscq' (Prunus Batsch L.), 'Flordaguard' [Prunus L. Batsch Prunus davidiana (Carr.)], 'Nemaguard' [Prunus L. Batsch Prunus davidiana (Carr.)], 'Okinawa' (Prunus Batsch L.) and Umezeiro (prunus mume Sieb & Zucc), forming graft/rootstock combinations.

The training system was in a “V” shape and the spacing between rows was 5m and between plants 1,5m.

Peach production was not influenced by the rootstock in site 1. In site 2 (EEA UFRGS), for the yield components, the analysis of variance was not significant in relation to Chimarrita and Maciel peach trees. In the Chimarrita over Umezeiro combination, the yield components were only evaluated in 2011. In previous years it was not possible to obtain fruit for evaluation. It can be inferred that this rootstock at site 2 (EEA/UFRGS) is not advisable due to production instability.

This is possibly associated with two combined factors: the sensitivity of Umezeiro to replanting areas combined with the low vigor of the Chimarrita cultivar, since the Umezeiro rootstock already has low vigor, either due to the fact that it is dwarfing or because it provides at the point of grafting swelling that generates a certain degree of incompatibility.

At site 3 (CAP/UFPel), the analysis of variance was significant only for the number of fruits per plant for the peach cultivar Chimarrita and productive efficiency based on kilograms of fruit per m3 of canopy for cultivating Maciel peach trees. The number of fruits did not differ significantly between rootstocks. The Umezeiro rootstock induced greater productive efficiency (kilo of fruit per m3 of canopy) to the Maciel peach tree, compared to the others. 'Capdeboscq' and 'Okinawa' were in an intermediate group and 'Adrighi', 'Flordaguard' and 'Nemaguard' provided lower production efficiency based on canopy volume.

This fact must have possibly occurred because although the Umezeiro rootstock induces less vigor, due to the fact that it is dwarfing or because it has a certain degree of incompatibility (due to the formation of swelling at the grafting point), it makes better use of the scion that it provides to the cultivate Maciel. Because even though it is smaller, it produces more fruit per m3. Obviously the Maciel cultivar itself also contributes to this fact, as it is more vigorous than Chimarrita.

High production efficiency and low vigor are important advantages for a high-density production system. This fact draws attention to the peach cultivar Maciel grafted onto Umezeiro in location 3, however there is still the fact of incompatibility to a certain degree as confirmed by visual observation of swelling at the grafting point.

It is believed that these divergences occurred due to the fact that in the present experiment three-year averages were used, slightly reducing the influence of each year's environment, in addition to the fact that each experimental unit that makes up the replications causes great variation in this aspect. due to differences in income, making the coefficient of variation high. The aforementioned authors worked with data from each year individually, being more susceptible to environmental variations than to the rootstocks.

The fruit quality component variables come from the average of the three years of evaluation (2009, 2010 and 2011), with the exception of the Umezeiro rootstock in location 2 (EEA/UFRGS) for the Chimarrita cultivar, which are only from 2011 , due to the fact that in 2009 and 2010 no fruit was obtained for evaluations.

For site 1 (Embrapa Uva e Vinho), the analysis of variance was not significant for color, only for titratable acidity of fruits from Chimarrita and Maciel peach trees. For fruits from the Chimarrita peach tree, there was no statistically significant difference between the rootstocks for titratable acidity. The rootstocks 'Flordaguard', 'Nemaguard' and 'Okinawa' induced higher titratable acidity for peaches from the Maciel cultivar compared to the other rootstocks.

For locations 2 (EEA/UFRGS) and 3 (CAP/UFPel), the analysis of variance was significant for more than one component variable of fruit quality, for this reason it was possible to carry out multivariate analysis and observe the dissimilarity between the carriers. grafts.

The fact that the Umezeiro rootstock provided different characteristics from the others to the Chimarrita cultivar can be explained by its characteristic of reduced vigor, because it is dwarfing or presents a certain degree of incompatibility. With less vegetative growth, the fruits are more exposed to light, and for their protection they develop a more intense red color. The ripening process also accelerates.

At site 3 (CAP/UFPel) it was also possible to observe the formation of three groups of rootstocks: group I ('Capdeboscq', 'Flordaguard', 'Nemaguard' and 'Okinawa'), group II ('Aldrigui') and group III (Umezeiro). The variables used for this analysis were titratable acidity, Ratio SS/AT and pulp firmness (N). The two canonical variables expressed 95,84% of the data variability. A greater relative importance was observed for the variables Ratio SS/AT and pulp firmness (N), totaling 72,20% of the responsibility for the divergence between the rootstocks.

At site 3 (CAP/UFPel), the Umezeiro rootstock induced a higher SS/AT Ratio and, together with the rootstocks 'Capdeboscq', 'Flordaguard', 'Nemaguard' and 'Okinawa', lower pulp firmness (N) at cultivate Maciel. In this sense, the Umezeiro rootstock provided an interesting characteristic to the Maciel peach cultivar for site 3 (CAP/UFPel). This can be explained by two factors: the Umezeiro rootstock gives less vigor, providing greater exposure of the fruits to light, advancing the maturation process or, also, by the fact that the data come from three years of cultivation, in 2010 and 2011, during the maturation period, little rainfall was observed, concentrating more soluble solids and increasing the SS/AT Ratio, since they are directly proportional.

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Conclusions

The yield components were little influenced by the rootstocks after three years of cultivation, with only variations depending on the cultivation region evaluated;

Quality components were most affected by rootstocks in the EEA/UFRGS (site 2) and CAP/UFPel (site 3) regions;

The Umezeiro rootstock is not recommended for location 2 (EEA/UFRGS), combined with the Chimarrita peach tree, due to the lack of production in 2009 and 2010, however, it is recommended for location 3 (CAP/UFPel) combined with the peach tree Maciel due to production efficiency and higher SS/AT Ratio;

The rootstocks 'Aldrighi', 'Capdeboscq', 'Flordaguard', 'Nemaguard' and 'Okinawa' can be recommended for Chimarrita and Maciel peach trees in the three cultivation sites (Embrapa Uva e Vinho, E.E.A UFRGS and CAP UFPel).

Click here to read the article in Revista Cultivar Hortaliças e Frutas, issue 79.

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