Hexose Characteristics of Peach Fruit and Leaves

In a study of 146 peach genotypes over two successive years, fruit from nearly all Chinese, Japanese, European and American bred cultivars, and most native Chinese cultivars, exhibited glucose-to-fructose concentration ratios of about 1 (normal G/F). Sixteen of 43 native Chinese cultivars, 4 wild species from different regions in China, Prunus kansuensis, P. ferganensis, and the European rootstock 'Siberian C' contained a much higher glucose concentration than fructose for a G/F ratio of 2.3-7.6 (high G/F), while P. davidiana had a low G/F of 0.8-0.9. The results showed that it is likely that Chinese wild species are the origin of gene(s) controlling low fructose concentration, and that genes controlling low fructose may be derived from either materal or paternal parents. The characteristic G/F for a peach genotype was independent of environment (year and developmental period). Moreover, leaves of peach cultivars that produced high G/F fruit tended to show higher G/F than leaves of peach cutlivars that produced normal G/F fruit.