Snapshots – International Avocado Research Update This series of research snapshots is compiled from abstracts of published scientific papers accessed through CAB Direct as well as Google Scholar searches. Dates provided reflect the date research was published.
Protected Growing Systems Evaluation of aerial and root plant growth behavior, water and nutrient use efficiency and carbohydrate dynamics for Hass avocado grown in a soilless and protected growing system Avocado production is nowadays questioned worldwide and at risk due to climate change and the high water footprint of this crop. Thus, there is need for the development or adoption of new strategies such as alternative production systems. In this study, Hass avocado plants grafted on two rootstocks (Mexicola -seed propagated and Dusa® vegetative-propagated and referred as clonal) were grown in a greenhouse and substrate (coir growth container, 55 L of volume and 500×480 mm, H X W) culture system in Valparaiso Region, Chile. Plant growth and development during the vegetative and reproductive phases until end of flowering (63 weeks) were monitored. Plant aerial and root parameters from these two rootstock types (seed and clonal) were monitored by measuring canopy and trunk area, trunk height, root area, type of roots (rhizotron), non-structural carbohydrates dynamics, further primary metabolites, water use efficiency (WUE) and nitrate and phosphate use efficiency (NUE and PUE). Results of this study corroborated that continuous fertigation with nutrient solution provide better growing conditions resulting in prolonged and more continuous growth and flowering than open field conditions. In addition, differences in aerial and root growth between plants grown on these two different rootstocks under similar fertigation and environmental conditions were found. Plants grown on Mexicola rootstock were more efficient energetically as sustained by higher trunk area, tree height and higher root content of the main non-structural carbohydrates (mannoheptulose and perseitol) than plants grown on the clonal rootstock. Our findings suggest that this alternative growing system for Hass avocado, besides being more intensive could have a positive impact on environmental indicators (WUE, NUE and PUE) related to sustainability. Read the paper here: https://bit.ly/3uHl4i3.
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RESEARCH AND DEVELOPMENT
Fruit Quality Chemical characterization of two Californiagrown avocado varieties over the harvest season with an emphasis on sensory-directed flavor analysis The research objective was to characterize avocado’s aroma-active volatiles and use information about its overall composition, such as lipid profile, to discuss likely biosynthetic origins. To achieve this, two varieties, Hass and “3-29-5” (GEM), were evaluated during their commercial harvest period for dry weight, moisture content (freeze-drying), oil content (Soxhlet extraction), fatty acid composition, and aroma profile. Solvent-assisted flavour evaporation and aroma extract dilution analysis were performed on aroma extracts. Oleic acid (>50%) was the prominent fatty acid in the oil of both varieties. The majority of the aroma-active compounds in avocado are lipid-derived. The most notable compounds are 1-octen-3-one (mushroom) with a flavour dilution factor as high as 8192, hexanal (grassy), (Z)-4-decenal, an unknown, and (E,E)-2,4-nonadienal. Over the mid-to-late harvest season, a decline in hexanal and an increase in octanal were observed. In contrast to “Hass”, the hexanal content was relatively stable in “3-29-5”. Read the paper here: https://bit.ly/2R5pKjg.
Irrigation Monitoring In situ measurement of plant hydraulic conductance Measuring sap flow together with stem water potential and stem water storage can provide an abundance of information about the functioning and physiology of the water-conducting xylem, including its hydraulic conductance and capacitance. As xylem grows, develops, and ages, it changes its capacity to conduct water, as new vessels and tracheids are formed and older ones become dysfunctional when filled with gas, gels, or tyloses. Environmental factors, such as drought, heat waves, irrigation, or flooding can also strongly affect hydraulic conductance and water storage in stems. Some plants even can influence hydraulic conductance by changing the ionic composition of their xylem sap. Destructive measurements using cut stems are the current standard method for measuring hydraulic conductance, but this method is prone to artifacts that could introduce significant differences to actual conductance in intact plants. Continuous, non-destructive
TALKING AVOCADOS AUTUMN 2021
