Stresses faced by quinoa as a consequence of its expansion to new environments

BERTERO, H D

Jinan, Shandong Province

Simposio; Taishan Academic Forum on Plant Stress Biology; 2017

Chinese Academy of Sciences and Shandong University

Expanding the range of cultivation of a crop implies new challenges not faced in the traditional areas of cultivation. This is the case of quinoa, an andean crop which was introduced to all continents at a fast speed in the last years. Some of the reasons for it being tried in many countries are its adaptations to salinity, water deficits and low temperatures, and this is reflected in the number of publications dealing with these factors impacts on this crop. Some new stresses are faced however, like high temperatures, waterlogging, preharvest sprouting or fast seed deterioriation. Staring with crop establishment, low quality seeds are a serious limitation. Quinoa behaves as an orthodox seed tolerating dessication with faster aging at high humidity and temperatures. Seeds from dry environments in the Andes age much faster than those from more humid environments in the Chilean lowlands and, although conditions during seed development are expected to affect future seed vigor and viability, the effect of those conditions have not been characterized yet. Concerning pre-harvest sprouting, most cultivars lack dormancy at harvest but there is variation for the trait. Dormancy is higher when seeds development occurs under long days and high temperatures but its expression is higher for seeds germinating at low temperatures. The highest dormancy is found in an accession from the humid island of Chiloe in central Chile and is associated to high sensitivity to abcisic acid and thicker seeds. Silty soils pose two aditional problems for crop stablishment; the small seeds are unable to overcome soil crusting and compactation and there is an increase in the risk of anoxia by waterlogging. Even very short waterlogging periods can lead to seedlings death and strong growth inhibition. Quinoa capacity to produce a high amount of biomass and yield under potential conditions is very high, but growth is slow early in the cycle because of slow leaf apperance and low radiation use efficiency under low temperatures, this delay also reduces the capacity to compete with weeds. There is great variation in terms of branching capacity and habit, panicle type and compactness offering a huge range of phenotype possibilities and short, determinate plants with higher harvest indices have already been developed for mechanized agriculture, particularly in Europe. One particular limitation is seed size, besides those grown at high altitudes and under winter sowings seeds are smaller than those produced in the high Andes reducing commercial quality. Finally, high temperatures seem to limit yield by reducing leaf area, radiation use efficiency and pollen viability.