Effects of ICerasus humilis/I I. Sok./I Rootstock on Peach Growth, Development, and Expression of Growth-Related Genes

Peach trees play an essential role as an economic crop in China. However, the increasing cost of labor has led to a decline in the benefits of peach cultivation. The use of dwarfing rootstock technology can increase planting density, reduce tree height, decrease labor requirements, and reduce production costs. The Cerasus humilis (Bge). Sok. is a promising dwarfing rootstock for peaches owing to its small tree size, abundant resources, strong resistance, and adaptability. In this study, we investigated the effect of Cerasus humilis rootstocks on peach growth and development, and related gene expression. We used Ruipan 4/Cerasus humilis and Ruipan 4/Amygdalus persica L. as experimental materials to measure the growth and fruiting characteristics of two-year-old Cerasus humilis rootstocks. In addition, we used bioinformatic methods to explore the effect of Cerasus humilis rootstock on peach growth gene expression. Our results showed that Cerasus humilis rootstocks can dwarf peach trees, reduce branches, increase pollen count and stigma receptivity, shorten spore development, and promote protein accumulation in the late stage of fruit maturity. The Cerasus humilis rootstock reduced the growth hormone content in peach trees while upregulating the expression of growth-related PpYucca5 and PpYucca2 genes. PpYucca6 expression was downregulated in the early stage of shoot growth and upregulated in the middle stage. By reducing the content of growth hormones, peach trees can be dwarfed, but their impact on fruit quality is minimal. These results indicate that Cerasus humilis is a suitable peach dwarfing rootstock and can provide a theoretical reference for the future breeding of peach dwarfing rootstocks.