The effects of strigolactone treatments on yield and quality in grapevine sapling

In this study, the individual and combined effects of different doses of GR24 (synthetic strigolactone analogue) and 2000 ppm of IBA (indole-3-butyric acid) on root and shoot development and sapling yield were evaluated under greenhouse conditions for the Narince/110R graft combination during potted grapevine sapling production. Grafting was performed at the bench in March using the omega-cut method. Subsequently, the cuttings were sealed with paraffin at 74-76°C and placed into crates filled with pine sawdust. The grafted cuttings were kept in a callusing (forcing) room with 85-95% relative humidity and ventilation provided every 6-12 hours. The temperature regimen was as follows: 3 days at 28-29°C, 15 days at 25-26°C, and 3 days at 22-24°C. When color change was observed in the callus tissue of the grafted cuttings kept under these conditions, a second paraffin coating was applied. Cuttings with over 75% callus development were treated prior to planting with individual and combined applications of GR24 and 2000 ppm IBA using a quick dip method (10 seconds). The treated cuttings were then planted into pre-prepared black polyethylene bags (12×20 cm in size, 2% UV-stabilized). A 1:1 mixture of perlite and peat was used as the potting substrate. The study evaluated parameters such as the degree of callus and root development, sapling yield (%), root and shoot length (cm), number of roots and leaves, fresh and dry weight of roots (g), fresh and dry weight of shoots (g), and dry matter content (%) of roots and shoots. As a result of the research, it was observed that especially low dose GR24 application had significant and positive effects on physiological properties such as root architecture, shoot length, number of nodes and dry matter ratio, while high dose GR24 and GR24+IBA combinations were observed to suppress both root and shoot development.