Genetic Relationship, SPAD Reading, and Soluble Sugar Content as Indices for Evaluating the Graft Compatibility of Citrus Interstocks

Abstract

The interstock, a stock between the rootstock and scion, has a significant regulatory effect on the stock and scion, and its function is highly dependent on graft compatibility. To assess the graft compatibility of the interstock and scion, ‘Yuanxiaochun’ was top grafted onto ‘Ponkan’, ‘Shiranuhi’, ‘Harumi’, ‘Tarocco’, and ‘Kumquat’. The results showed significant differences in the survival ratio and preservation ratio among different combinations. Grafting compatibility in the early stages of grafting was associated with the genetic relationship. The biomass accumulation revealed that the interstock could influence both the rootstock and the scion. The physiological and biochemical traits analysis suggested that SPAD reading and soluble sugar could be employed as preselected indices to evaluate graft compatibility in the late stage of grafting. These results indicated that the evaluation of graft compatibility was a dynamic process. The findings provided a new approach for studying the stock and scion interaction mechanisms mediated by interstock, and directly provided a theoretical and practical basis for the high-grafting of ‘Yuanxiaochun’ citrus.

Morphological, physio-biochemical and nutritional status as potential markers for grafting compatibility in Kalamata olive cultivar

“…Recent studies have reported that, SPAD reading which is an indicator of chlorophyll content or photosynthetic activity can be used as a compatibility indicator between scion and rootstocks [ 13 , 33 ]. Studies have shown that the differences in the effects of different rootstocks on the scion behavior are mainly appeared in the leaves.…”

“…These results were consistent with Moing et al [ 32 ]who found that, soluble sugars accumulated in the scion were coincided with grafting incompatibility, since rootstocks in more incompatible combinations resulted in more soluble sugar accumulation in the scion. More recently, Wang et al [ 13 ] reported that the lowest survival rate was recorded in ‘Harumi’ as an interstock in apple grafting which accumulated higher sugars content and showed smaller leaf area and symptoms of incompatibility.…”

“…More recently, soluble sugar content and SPAD value (chlorophyll indicator) may be used as indices to assess graft compatibility in grafting citrus [ 13 ]. Also, Miao et al [ 14 ] found that, sugars had a stimulative effect on graft union development in cucumber/pumpkin grafting combination.…”