Abstract

The ‘norte chico’ zone of northern Chile (Regions of Atacama and Coquimbo) is characterized by low rainfall and frequent droughts which severely hamper the performance the economically relevant fruit production industry. In order to develop alternatives which can better cope with this conditions we assessed Opuntia germoplasm as a low water requiring fruit production alternative. Five experimental plots were established in locations that represent the agroclimatic diversity of the ‘norte chico’. The climatic diversity fo this zone is mainly driven by two gradient vectors: (i) Andes mountain valleys (east; high) – Pacific ocean costal ranges (west; low) and (ii) drier (north; Atacama) – less dry (south, Coquimbo). In order to capture these vectors two plots in Atacama (high and low) and three in Coquimbo (high, middle and low) were chosen and the early adaptation of 5 clones of Opuntia were evaluated during two growing seasons: ‘verde’ (1V; typical Chilean genotype, used as reference); ‘naranja’ (2N), ‘salmón’ (3S), ‘morada’ (4M) and O. amyclea (5AMY). Growth and development variables of the plants were measured, and related with climatic variables. Genotypes showed similar growth and development in all orchards, except in the middle valley of Atacama (less than others), while canopy volume of plants were higher in orchards of Coquimbo. In terms of the relationship of growth and development with climatic variables, we found that canopy volume and cladode production rate were promoted by higher photo-thermal quotient and higher minimal temperatures during spring and summer (above 11°C). The latter result confirms the positive effect of warm nighttime temperature on Opuntia metabolism. Regarding clones, 4M and 2N showed higher cladodes/plant than the reference genotype, and 3S and 5Amy had lower canopy volume than the rest. In high Atacama and middle Coquimbo, all clones, at the exception of 5Amy, bore fruit during the second season. Irrespective of genotype, average fruit weight was 70 g higher in middle Coquimbo than high Atacama. Comparing to our reference, the fruit weight was similar for 2M, lower for 4M and higher for 3S, all plots taken together. Taken together, planting 3S in middle Coquimbo appears as the most promising combination.