Quantitative and Qualitative Characteristics of Various Grape Cultivars Through Cion Grafting Based on the Shirazi Cultivar Under Rainfed Conditions

Grape (Vitis vinifera L) is one of the most important horticultural products globally and in Iran, having been used by humans for centuries. Undoubtedly, the goal of establishing a vineyard is to achieve high yield, sustainable production, and economic viability, which is influenced by various biological and abiotic factors. Among these, the cultivar plays a key role in the success of vineyard production. In this regard, one of the best options for improving the vineyard is changing the cultivar to superior commercial varieties using the cion grafting method. To this end, an evaluation of commercial grape cultivars (Resheh, Torkaman 4, Flame Seedless, Crimson Seedless, Red Seedless, Superior, Scarlett, and Perlette) was carried out in a rainfed vineyard located in Noorabad Mamasani in the Doshman Ziari region, based on the Shirazi cultivar. Traits assessed included grafting success and quantitative traits such as cluster weight, number of clusters, cluster length and width, berry weight, number of berries, yield, and qualitative juice traits including TSS, TA, and TSS/TA ratio. The results showed that under rainfed conditions, the cultivar had a greater effect on both quantitative and qualitative traits compared to the grafting method. The highest cluster weight in rainfed conditions was observed in the Crimson Seedless cultivar (420.9 g), while the lowest cluster weight was in the Flame Seedless cultivar (296 g). The highest yield per plant was obtained in the Resheh cultivar (4.31 kg per plant), while the lowest yield per plant was in the Superior cultivar (3.6 kg per plant). The highest maturity index or Brix-to-acid ratio was observed in the Red Seedless cultivar, similar to the Torkaman 4 cultivar, while the lowest ratio was recorded in the Superior cultivar. The Torkaman 4 and Flame Seedless cultivars were earlier-maturing than the others and could be harvested at the same time as the unripe Shirazi grapes.