The popularity and demand for avocado (Persea americana) have increased tremendously. Like many other clonal crops, a few varieties and rootstocks dominate the avocado market. Nowadays, avocado trees are conquering new farming areas. However, at the same time, they are facing new threats, such as new pests and changing environmental conditions. The search for clonal rootstocks that can better adapt to the biotic and abiotic stress conditions is one of the challenges. That could be solved using the large reserve of genes present in the avocado germplasm because there is a diversity in the native areas where the avocado originated. Thus, the creation of Shepherd-Brokaw Orchard at The Huntington as a field avocado collection was our first attempt to preserve avocado diversity. Thirty-three different avocado cultivars, clones with importance in the history of the avocado industry in California, were selected for this purpose. However, ideally, we should be able to secure the avocado crop and its wild relatives with minimal cost, maximum diversity, and no loss through time.
Avocado propagation is very slow and labor-intensive, limiting plants' availability for growers and increasing their final cost. Although various protocols reported micropropagation of some avocado clones of interest, the mass propagation of avocado for most commercial rootstocks and cultivars needs optimization. It is broadly accepted that shorting the propagation time in the nurseries will increase the plants' availability for growers and decrease their final cost. Our approach to clonal micropropagation of avocado primarily focused on rootstocks of interest for the California industry and The Huntington field collection.
