Merensky 5 Avocado Rootstock Salinity and Disease Resistance
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Solution Overview
Problem
Avocado trees are susceptible to root rot caused by Phytophthora cinnamomi and are sensitive to high salinity, leading to economic losses and reduced fruit yield and quality, with existing varieties failing to provide adequate resistance or tolerance.
Innovation Solution
Development of the 'Merensky 5' avocado rootstock, which exhibits superior tolerance to salinity and Phytophthora cinnamomi, allowing for increased fruit yield when 'Hass' trees are grafted onto it, and is propagated using a nurse seed/etiolation system for clonal trees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If avocado trees are grown in areas with high salinity, then fruit yield and quality are reduced, but the trees continue to be exposed to harmful salt conditions
Solution Approach 1:
The avocado system is divided into two functional parts: the scion (fruit-bearing portion) and the rootstock (soil-interacting portion). The 'Merensky 5' rootstock is specifically selected and bred to tolerate high salinity conditions, while the scion can be any desired avocado variety. This segmentation allows the rootstock to withstand harmful salt conditions without transmitting this stress to the fruit-producing parts, thereby maintaining both salinity tolerance and fruit yield/quality.
Solution Approach 2:
The rootstock acts as an intermediary between the harmful saline soil environment and the sensitive scion. The 'Merensky 5' rootstock mediates the interaction by absorbing and tolerating the salt stress, protecting the scion from direct exposure to harmful conditions. This intermediary function enables the tree to thrive in saline environments while maintaining high fruit production.
2Object-affected harmful factors
If avocado trees are exposed to Phytophthora cinnamomi, then root rot and death occur, but the pathogen is widely distributed in soil
Solution Approach 1:
The avocado system is divided into scion and rootstock, with the rootstock specifically bred for disease resistance. The 'Merensky 5' rootstock contains genetic resistance to Phytophthora cinnamomi, isolating the sensitive scion from direct pathogen exposure through the root interface. This segmentation allows the rootstock to withstand pathogen attack while protecting the fruit-bearing portions.
Solution Approach 2:
The rootstock provides beforehand protection against Phytophthora cinnamomi infection. By selecting 'Merensky 5' rootstock with inherent resistance, the system is pre-cushioned against the pathogen threat before exposure occurs. The rootstock's resistance acts as a protective barrier that prevents the pathogen from reaching and infecting the scion, ensuring tree survival and continuous productivity.
3Object-affected harmful factors
If existing avocado varieties are used, then market preference for Hass fruit is maintained, but adequate resistance to root rot and salinity is not provided
Solution Approach 1:
The system separates the functions of fruit quality (scion) from stress tolerance (rootstock). The scion can be Hass or any other variety that produces market-preferred fruit, while the rootstock is specifically 'Merensky 5', bred for resistance to Phytophthora cinnamomi and salinity tolerance. This segmentation allows simultaneous achievement of high fruit quality and strong stress resistance.
Solution Approach 2:
The 'Merensky 5' rootstock serves multiple functions: it provides Phytophthora resistance, salinity tolerance, and supports high fruit yield. This multi-functional rootstock can be used with various scion varieties, making it a universal solution that addresses multiple problems (disease, salinity, and productivity) simultaneously, regardless of the desired fruit variety.
Data Source
AI summary
A new avocado variety, ‘Merensky 5’ has high tolerance to salinity and to Phytophthora cinnamomi when used as a rootstock. ‘Hass’ trees grafted onto the ‘Merensky 5’ rootstock bear good yields.