Pre-harvest factors influencing “Hass” avocado quality during long term storage

1. Pre-harvest factors influencing “Hass” avocado quality during long term storage Bruno Defilippi1, Paula Robledo1, Raúl Ferreyra1, Sylvana Soto1and Jorge Saavedra2 At harvest 1Instituto de Investigaciones Agropecuarias, CRI-La Platina, Unidad de Postcosecha. Santiago-Chile 2Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile Email: bdefilip@inia.cl www.inia.cl/postcosecha Frequency Chile is an important avocado supplier in the world exporting a 60% of its production, mainly to USA, followed by Europe. Most of this volume reaches the market in controlled atmosphere containers; however, still a major challenge for the Chilean industry is to provide a homogenous fruit in terms of quality, especially considering that an important variability could be found in maturity stages of the fruit within a box or a pallet. Part of this variability is due to the broad range of conditions in which trees are grown, especially in terms of climate and soil, and also associated with different cultural practices used among avocado growers. In the last four years, we have been performing a project in order to understand this variability by determining the effect of pre-harvest factors on the postharvest life of avocados cv. Hass, shipped under regular air (RA) and controlled atmosphere (CA, 4% O2 and 6% O2) conditions. Among the variables studied, the days between flowering and harvest had an inverse effect on fruit firmness level after storage. A similar behavior was found for N/Ca ratio and oil content at harvest. Firmness (lb-f) 35 days at 5 °C (RA) Frequency Experimental approach Results Firmness (lb-f) 1. The use of CA on avocado showed several benefits in terms of fruit quality, compared to RA storage, including a delay in pulp softening and retention in color development. However, there were important differences in the efficacy of both treatments among growers. Preharvest factors Harvest (9-10% oil content) RA storage at 5°C Shelf-life at 20 °C CA storage at 5°C Daystoreadytoeatstage (< 2 Lbf) 3. What factors are affecting postharvest? The most important factors determining firmness were: time between flowering and harvest (diascosech), calcium content in the fruit at harvest (TFCa), orchard height (Altitud), nitrogen/calcium ratio in the flesh at harvest (N/Ca), fruit dry matter (MSeca0), and all of them located far from the center of the PLS model (R2Y = 80.3% ; Q2 =66.7%). *CA storage = 30 days CA + 25 days RA storage *CA storage = 30 days CA + 10 days RA storage 2.Why do we have these differences in efficacy?. In the first 3 seasons, we characterized and identified the main factors determining the variability in postharvest storage potential of 46 growers under RA storage. For firmness and color development there was a high variability for both parameters after 35 d. of storage, with fruit on a ready to eat stage at the end of storage for some growers (<2 lb-f or black color), while others still with a firm fruit (> 50 lb-f and green). Color Scale 1 2 3 4 5 Final remarks A high fruit variability among growers was observed in the quality parameters studied after long term storage. Apart from the benefits already mentioned, the use of CA reduced this variability. Among the factors studied, days between flowering and harvest had an inverse effect on fruit firmness level. Other factors with a similar behavior were ratio N/Ca at harvest and dry matter content. Presently, we are working in the following approach in order to elucidate the underlying mechanism determining postharvest performance of avocado under CA storage. soft firm soft firm Funded by: Innova- CORFO