Document Type : Research Article
Authors
1
Crop and Horticultural Science Research Department, Markazi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Arak, Iran
2
Department of Agriculture, Payame Noor University (PNU), Tehran, Iran
Abstract
Introduction
Top-working is one of the propagation and improvement techniques for fruit trees, which is also applied in grapevines to enhance fruit quality, change cultivars, increase disease resistance, and improve adaptability to climatic conditions. This method allows growers to graft new and desirable cultivars onto existing rootstocks without removing old vines, enabling production in a short period. Therefore, in this research, conducted between 2022 to 2024, the aim was to diversify the predominant grape (Vitis vinifera) cultivar (Bidaneh-sefid) in Shazand, Markazi province, by grafting foreign cultivars onto mature rootstock in local grapevines (Bidaneh-sefid).
Materials and Methods
The experiment was conducted as a split plot in a randomized complete block design with three replications. The experimental treatments included the main plot assigned to two grafting methods (Hard-cleft grafting and Green-cleft grafting) and the sub-plot assigned to six foreign-commercial grape varieties as scion (Turkmen-4, Flame seedless, Rubi seedless, Perlette, Autumn King, Autumn Royal). In the first year, the percentage of grafting success, scion growth (cm) and the percentage of damage caused by winter and late spring cold stress were evaluated. Subsequently, in the third year, at the physiological mature stage of grape fruits, the interaction effect scion and rootstocks on some quantitative (berry length: mm, berry diameter: mm, berry weight: g, cluster length: cm, cluster width: cm, cluster weight: g and yield: kg.vine-1) and qualitative (flavor index and total soluble solids: TSS) traits of the fruit were evaluated. Afterwards, to analysis data, the normality test of the data for all measured traits (except the percentage of damage caused by cold stress) was performed based on the Kolmogorov-Smirnov test, then the variance analysis of the data was performed using the GLM procedure and the comparison of means was performed using the least significant difference (LSD) test at a probability level of P< 0.05 with SAS software. In order to compare the percentage of damage of scions caused by cold stress, the ratio test and Fisher's z test statistic were used using SPSS ver. 28 software. Cluster analysis and grouping of varieties were performed using the WARD method and using Euclidean distance for the first year data, simple correlation coefficient between quantitative traits related to fruit, Principal Component Analysis (PCA) to identify internal relationships between the studied varieties (rootstock and scions) and some measured traits in the third year, followed by biplots drawn between the characteristics and varieties based on Stat Graphics software version 11/1/16.
Results and Discussion
Based on the results of analysis of variance, the simple effect of variety and the interaction effect of graft-variety were significant (p≤0.01) and non-significant, respectively, for all evaluated traits. On the other hand, the simple effect of graft on all evaluated traits except fruit quality indices was significant (p≤0.01). The highest percentage of grafting success and one-year scion growth was obtained by the green-cleft grafting and hard-cleft grafting methods, respectively. The results of the assessment of damage caused by winter cold and late spring cold in the first year indicated greater sensitivity of vines grafted using the green-cleft grafting method compared to the hard-cleft grafting method. On the other hand, vines grafted using the hard-cleft grafting method had the highest values of yield components and fruit yield in the third year. Based on the grouping of varieties using the Ward method and Euclidean distance, two cultivars, "Autumn Royal" and Turkman-4, achieved superior positions compared to other varieties in terms of the evaluated traits in the first year. On the other hand, all varieties evaluated as scion had acceptable values of total soluble solids (TSS) and fruit flavor index. Regardless of the type of grafting method, due to the non-significant interaction effect of graft-variety on the measured traits in the third year, the results of principal component analysis and biplot based on the first component (yield and components correlated with yield including berry length, berry diameter, and berry weight) and the second component (TSS and flavor index) showed that the varieties "Autumn Royal" and "Turkmen-4" were superior compared to other varieties (scions and rootstock).
Conclusion
In summary, the results of the present study indicate that the cleft-grafting method, the selected time, and the environmental conditions of the Shazand region were suitable for grape grafting. The two varieties "Autumn Royal" and "Turkmen-4" can be introduced as appropriate candidates for grafting grapevines in the Shazand region with the "Bidaneh-sefid" rootstock using either green or hard-cleft grafting methods due to the desired economic performance. Besides, the "Turkmen-4" variety, due to its early maturity, and the "Autumn Royal" variety, due to its late maturity, can be recommended for areas of the Markazi province with early autumn rainfall and areas with long summers, respectively.
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