Following more than two decades of thorough testing as part of its rootstock breeding and screening programme, the Westfalia Fruit Group has released two new avocado rootstocks, co-owned with the South African Avocado Growers’ Association (SAAGA), for commercial sale under the Merensky name.

Trees of these two new avocado rootstocks are being trademarked under the names Leola (Merensky 6) and Zerala (Merensky 5).

According to Wetsfalia, the novel rootstocks yield healthier trees and better-producing orchards under challenging growing conditions than other industry-standard rootstocks, as confirmed in recent trials.

The rootstocks have been released in the US and South Africa, with commercial roll-out to be expanded as further trials deliver similarly positive results.

For almost 40 years, Westfalia’s R&D division, Westfalia Technological Services, has been researching disease-tolerant clonal rootstocks to develop selections with superior tree health and yields.

The group’s existing avocado rootstocks Latas (Merensky 1) and Dusa (Merensky 2), which were successfully developed and tested over two decades, have enjoyed "increasing success" with the support of loyal licencees, specifically Brokaw Nurseries from Ventura, California, and its affiliates across the Spanish-speaking world.

"These rootstocks offer high root-rot tolerance and higher yields, with Dusa also offering some salinity tolerance," the group explained. "To date, Dusa has been the top seller among clonally propagated rootstocks worldwide.

"Protected under Plant Breeders’ Rights, it is grown successfully in Australia, New Zealand, Spain, Israel, the USA, South America and South Africa. More than 1.5m Dusa trees are sold annually in the commercial market."

Now, with the launch of Leola and Zerala, co-owned by Westfalia and SAAGA, growers are presented with higher-yielding rootstocks developed to suit a range of growing conditions around the world.

Westfalia said that it supported the group’s reputation as ‘Avocado Experts’ and as a pioneer in the avocado industry, and also enhanced its ability to plant sustainable and productive orchards of its own.

The rootstocks were evaluated under a broad range of production conditions in various countries.

Demonstrating tolerance to Phytophthora cinnamomi root-rot under heavy infection pressure, Leola was shown to outperform Duke 7 – the previous industry-standard rootstock – in initial productivity screening, and even outperformed Dusa in recent trials.

In addition to being selected for its high standard of productivity, Zerala is Westfalia’s rootstock of choice for growing in areas facing salinity challenges.

Westfalia confirmed that both new rootstocks would continue to undergo large-scale monitored plantings and trials.

"The launch is of great significance to the global avocado industry, making greater yields possible under a range of challenging growing conditions and allowing larger volumes of fruit to be produced and marketed across the globe, to meet growing consumer demand," the group added.