Chile sits at the intersection of several of the world’s most challenging growing environments. Its agricultural regions span from the hyper-arid Atacama in the north to the cool, wind-battered vineyards of Patagonia in the south. In between, growers contend with some of the highest solar radiation levels on earth, temperature extremes that can shift by 20 degrees or more between day and night, and increasingly unpredictable drought patterns driven by the ongoing decline of Andean snowpack.
Abiotic stress is not an occasional event in Chile. It is the baseline condition. And that makes it one of the most instructive places to understand what a product like MARTELLO actually does in the field.
The Problem MARTELLO Was Built to Solve
Abiotic stress, meaning stress caused by non-living environmental factors such as heat, drought, cold, and salinity, is the single largest cause of crop yield loss globally. Heat stress alone is estimated to reduce crop production by more than 10% per degree of warming above the optimal threshold during critical growth stages.
The reproductive stage is particularly vulnerable. When temperatures rise above the thermal threshold during flowering, pollen viability drops sharply. Fewer viable pollen grains mean fewer fertilised flowers. Fewer fertilised flowers mean less fruit. Less fruit means lower yield, and this is true whether the crop is a tomato in a greenhouse, a table grape in the Maule Valley, or an avocado in the Coquimbo region.
The challenge is not just extreme heat. Chronic mild heat stress, temperatures consistently at the upper edge of a crop’s comfort zone, causes the same kind of incremental damage over a full season. It is less visible and harder to attribute, but the yield cost accumulates.
What the Science Shows
MARTELLO is built on PSI Technology using an aqueous extract of Ascophyllum nodosum at 36% concentration. Its mode of action under heat stress has been validated through controlled trials at Brandon Bioscience and published in peer-reviewed literature (Carmody et al., 2019).
The trials used tomato as a model crop, applying both unstressed conditions (27/22 degrees Celsius) and chronic mild heat stress (31/24 degrees Celsius). The results were significant across three key yield parameters.
Flower Number
Under heat stress, untreated plants produced an average of 23.6 flowers per plant. Plants treated with MARTELLO produced 33.6 flowers per plant, an increase of 42%. Even under unstressed conditions, MARTELLO increased flower numbers from 32.0 to 50.6 per plant, a 58% uplift.
Pollen Viability
This is where heat stress causes the most direct damage. In untreated plants under heat stress, pollen viability dropped to 19.9%. MARTELLO-treated plants under the same conditions maintained pollen viability at 63.5%, more than three times higher. Under unstressed conditions, both groups were comparable at approximately 98.6%, confirming that MARTELLO does not interfere with normal pollen development.
Fruit Number
The combined effect on flowers and pollen translated directly to fruit. Untreated stressed plants set 18.1 fruits per plant. MARTELLO-treated stressed plants set 31.3 fruits per plant, a 73% improvement in fruit set under chronic heat stress conditions.
The Mechanism Behind the Results
MARTELLO’s effectiveness against heat stress comes from four distinct but interconnected actions at the biochemical and molecular level.
First, it accumulates thermally protective sugars and heat shock proteins in flowers. Heat shock proteins, or HSPs, are molecular chaperones that help other proteins maintain their correct structure under thermal stress. Without them, proteins that are essential for pollen function and fertilisation begin to denature. MARTELLO upregulates specific HSPs including HSP101.1 and HSP70.9, providing active protection during heat events.
Second, it improves carbon and nitrogen metabolism under stress, ensuring the plant has the metabolic resources to continue fruit development even while managing a heat response.
Third, it increases pollen viability through the mechanisms described above, directly protecting the critical fertilisation step.
Fourth, it maintains the overall abiotic stress tolerance of the plant, preserving yield capacity not just during the heat event itself but through the recovery period.
What Chilean Farmers Experience
In Chile’s central valleys, where table grapes, stone fruits, avocados, and increasingly citrus are grown for export markets with tight quality specifications, heat events during flowering and fruit set are a recurring commercial risk. A single hot week at the wrong moment can significantly affect the proportion of marketable fruit and, by extension, the economic return of the season.
Growers using MARTELLO as part of their programme will see more consistent fruit set across varying seasonal conditions. In a crop like table grape, where uniformity of bunch size and berry number directly affects packing-house grade-out rates, this consistency has a direct commercial value that goes beyond headline yield numbers.
MARTELLO also offers good compatibility with calcium and acidic mix partners at pH below 4, making it straightforward to incorporate into existing spray programmes without the need for pH adjustment.
Thirteen Years of Trial Data
MARTELLO has been evaluated in 96 trials over 14 years across field, glasshouse, and growth room settings. Across that dataset, the product delivered an average yield advantage of 15% with an 85% win rate. This is the kind of long-run evidence base that allows agronomists to make confident recommendations.
MARTELLO improves flowering and fruit set under high and prolonged abiotic stress and in crop varieties with limited fruit set potential. Speak to our team regarding timing and application rates suited to you crop.
Explore the full range of Brandon Bioscience solutions or visit our published research for the detailed trial data.
