Selecting the right rootstock is crucial for citrus growers, especially for those cultivating Clementines. Recent findings reveal that rootstock choice significantly influences not only the productivity, but also the overall quality of the fruit. A recent report summarised results from a trial conducted in California’s San Joaquin Valley, focusing specifically on ‘Nules’ Clementine trees planted on various rootstocks.
In the trial, which was part of the Citrus Research Board-funded Core Breeding and Evaluation project, researchers evaluated the performance of Clementines on 22 different rootstocks. Among the most productive were ‘C35,’ ‘Bitters,’ ‘Rubidoux’ trifoliate, ‘Australian’ trifoliate, ‘Swingle,’ and ‘Carrizo.’ Interestingly, many of these high-yielding rootstocks tended to produce smaller-sized trees.
Why Rootstocks Matter
Rootstocks can have varying impacts on fruit size and overall quality, which is essential knowledge for growers aiming for a profitable harvest. The report highlights that opting for specific rootstocks demands careful consideration of their advantages and disadvantages, making it a significant decision for the future of citrus plantations.
Clementines are a rapidly growing crop in California and represent the most important early-season mandarins in the state. With limited trials available on their performance across different rootstocks, this study provides valuable insights. The trial was conducted at the University of California’s Lindcove Research and Extension Centre, where the researchers carefully selected the rootstocks based on previous studies and their performance with other citrus varieties.
Insights on Tree Size and Yield
The survival rate of the trees in this trial was impressively high at 97%. Those planted on rootstocks like ‘C35’ and ‘Bitters’ yielded the most fruit, while ‘Sun Chu Sha Kat,’ ‘Tosu,’ and a few others lagged behind. It’s noteworthy that trees on trifoliate orange rootstocks initially showed less alternate bearing but did not maintain this trend over time.
The study also measured tree size, with larger canopies resulting from rootstocks like ASRT, ‘Furr,’ and ‘Brazilian’ sour. However, only ‘Swingle’ among these produced high yields. The connection between tree size and yield is complex; rootstocks like ‘C35’ and ‘Carrizo’ demonstrated favourable yield relative to their canopy volume.
Quality Matters Too
Another important aspect of the research focused on fruit quality. Analysis revealed that certain rootstocks produced a higher percentage of larger fruit sizes. ‘Volk,’ ‘Tosu,’ and ‘C35’ stood out in this regard. However, the overall yield of these rootstocks didn’t always correlate with the number of large fruits produced, indicating that while some rootstocks yield larger fruit, others may provide more quantity without compromising size.
Interestingly, certain rootstocks like ‘Australian’ trifoliate and ‘Pomeroy’ trifoliate yielded fewer fruits in the desirable size categories. Therefore, growers need to weigh the trade-offs between the quantity and size of the harvest when selecting rootstocks.
Takeaways
The choice of rootstock is a significant decision that can influence both the yield and quality of Clementines. As citrus cultivation evolves, understanding these dynamics becomes ever more crucial for growers. The data presented in this study from the Citrus Research Board provides a critical foundation for making informed choices about rootstock selection.
For more detailed findings on this research, refer to the original report, linked here.
