Genotypic differences in cyanogenic glycosides levels of compatible Prunus persica P. persica and incompatible P. persica P. mume combinations
ABSTRACT Graft incompatibility is a phenomenon associated with complex physiological, biochemical, and genetic interactions between scion and rootstock. The main objective of this work was to assess the role of cyanogenic glycosides (CGs), amygdalin and prunasin, in the graft incompatibility of Prunus and possible biochemical effects in compounds of the phenylpropanoid pathway. Graft compatibility, amygdalin and prunasin content, phenylalanine ammonia-lyase activity, total phenolic compounds content and antioxidant activity, were studied in different graft combinations (Chimarrita/Capdeboscq; Chimarrita/Tsukuba 1; Chimarrita/Umezeiro; Maciel/Capdeboscq; Maciel/’Tsukuba 1; Maciel/Umezeiro) and ungrafted genotypes. The results indicate that there was graft incompatibility of Chimarrita and Maciel cultivars grafted into Umezeiro rootstock. Combinations identified as incompatible showed higher prunasin concentration and phenylalanine ammonialyase (PAL) activity in rootstock and greater concentration of total phenolics compounds and antioxidant activity in scion and rootstock. The results indicate that large differences in CGs concentration, especially prunasin, can be the graft incompatibility cause between Prunus persic. and P. mume. The prunasin concentration may be considered a promising marker to predict graft compatibility between P. persica and P. mume.