Pg. 15-17 Possible Rootstock Benefits for Litchi Cultivars

Plant grafting is an ancient technique known to the Chinese at least as early as 1 000 BC. Paul discussed grafting between the “good” and the “wild” olive tree with the Romans (Romans 11: 17-24). This art was passed on from generation to generation and the methods of grafting and budding published in 1891 (Bailey), differ very little from the methods used today. Today many of the fruit industries utilise grafting to great effect. This valuable horticultural method could have great value for the litchi industry as well. In this article we shall briefly indicate the value to other crops from using rootstocks and some of the current problems of the SA litchi industry that might be addressed by a
rootstock trial.

Summary:

• Grafting is an ancient horticultural technique with potential benefits for the litchi industry by using specific rootstocks to influence tree growth and fruit production.
• Rootstock-scion interactions are complex and affect the whole tree, including nutrient uptake, water translocation, growth factors, and anatomical traits.
• Rootstocks can significantly impact water requirements, shoot growth, precocity (early fruiting), productivity, fruit quality, and resistance to pathogens and environmental stresses.
• In other fruit crops, rootstocks have enhanced yield, precocity, fruit size, and quality, with examples including apples, cherries, peaches, pears, grapes, mangoes, and custard apples.
• Important rootstock effects include increased trunk size, improved flower density, altered branch angles that influence structural strength and wind resilience, and changes in dry matter partitioning between vegetative and reproductive growth.
• Rootstocks can modify water uptake and use, which is critical for litchi because water stress affects vegetative growth and flowering timing.
• Problems in the South African litchi industry such as delayed bearing, irregular yields, short season, large tree size, low productivity, poor fruit quality, and wind damage could potentially be addressed with rootstock selection.
• Rootstock genotypes may provide benefits like more consistent production, increased precocity, improved fruit development, and better retention by altering physiological processes.
• Wider branch crotch angles influenced by rootstocks could enhance wind damage resistance and support training to desirable tree shapes.
• A planned research project aims to evaluate how rootstocks could improve commercially relevant issues in litchi cultivation.
• Overall, rootstock-scion combinations hold significant promise to enhance litchi orchard performance and fruit market competitiveness.