Available water during the critical period for yield in chia (Salvia hispanica L.): effcets on yield and physiological components

DIEZ J.; ORELLANA F.; ACRECHE M.M.

Congreso; XXXIII Argentinian Meeting of Plant Physiology RAFV 2021; 2021

The climatic balance of the Temperate Valleys of Salta and Jujuy demonstrates the necessity of supplement rainfall with irrigation at the time when main yeild components of chia are defined. The objective was to evaluate the effect of levels of water availability during the critical period or yield in chia. The water availabilities were: control at field capacity (Tcc) and decreases of total available water of 34, 60, and 80% (T34, T60 and T80). Grain yield and its main components (number of grains, number of verticillasters and number of grains per verticillaster) decreased ca. 40% in T60 and T80, whereas the reduction in grain yield and number of grains was 20% in T34. The treatments T60 and T80 presented lower LAI (at 7-pairs of unfoldd leaves and flowering) and percentage of intercepted radiation (lower maximum PAR and lower rate of increase in interception) than Tcc, which resulted in lower intercepted accumulated radiation, total dry matter and radiation use efficiency. Crop evapotranspiration decreased 30-40% in T60 and T80 and 10% in T34. This reduction was associated with higher proportions of evaporation than transpiration during the critical period compared with Tcc, which resulted in lower water use efficiencies in T60 and T80. Sumarizing, water restriction during the critical period of chia affects grain yield and its main numerical and physiological components. Management strategies tending to reduce the high proportion of evaporation compared to transpiration should be designed.