Anatomical and biochemical investigation of grafting mechanisms in peach cv. J.H. Hale on different rootstocks

In this research, it was aimed to develop methodological protocols in order to explain the mechanism of graft incompatibility with different methods and to detect it early. 'J.H.Hale' peach cultivar was grafted onto 5 rootstocks 'peach seedling', 'Garnem', 'GF 677', 'almond seedling' and 'Myrobolan 29C'. Anatomical-histological investigations, biochemical analyzes and morphological observations were performed in compatible homograft and heterograft combinations and incompatible heterograft combinations. In all grafted combinations, the time of formation of callus tissue and the density of necrotic area showed differences according to the compatibility/incompatibility between the graft partners and whether they were homograft/heterograft. It was observed that 24 months after grafting, J.H.Hale/Myrobolan 29C graft partners were separated from each other with a clear line. It was found that the total phenolic and total flavonoid contents were higher in grafted plants than ungrafted plants. 24 months after grafting, the total phenolic content was determined the lowest in J.H.Hale/Peach seedling (32.97mg/g) and highest in J.H.Hale/Myrobolan 29C (68.14mg/g) combinations. Similarly, the lowest total flavonoid content was recorded in J.H.Hale/Peach seedling (15.19mg/g) and the highest in J.H.Hale/Myrobolan 29C (39.34mg/g) combinations. In peroxidase isoenzyme profiles, Rf=50 band was found in the incompatible heterograft J.H.Hale/Myrobolan 29C combination, and Rf=46 band was found in the compatible homograft J.H.Hale/Peach seedling combination. The highest peroxidase activity was determined in the incompatible J.H.Hale/Myrobolan 29C combination (7.8ΔAg-1dk-1), while the lowest peroxidase activity value was determined in the J.H.Hale/Peach seedling combination (4.1ΔAg-1dk-1). Ungrafted plants photosynthetic pigments were higher than grafted plants. Total chlorophyll-chlorophyll a values were highest in J.H.Hale/GF 677 (1.73mg/g-1.08mg/g) and lowest in J.H.Hale/Myrobolan 29C (0.42mg/g-0.29mg/g) combinations 24 months after grafting. In the morphological observations, J.H.Hale/Myrobolan 29C combinations were showed weak growth compared to the other grafted combinations.