VALIDATION OF CROP WATER STRESS INDEX (CWSI) BY INFRARED THERMOGRAPHY AND ITS IMPACT ON FRUIT YIELD AND QUALITY OF ‘ROYAL GALA’ APPLES

Celerino Quezada^{1 *}, Richard Bastias¹, Rodrigo Quintana², Raimundo Arancibia¹, Alejandro Solís¹

ABSTRACT

Infrared thermography is an efficient methodology to monitor plant water status under field conditions. The objective of this research was to validate the use of Crop Water Stress Index (CWSI) as an indicator of plant water status in ‘Royal Gala` apples and evaluate its effect on yield and fruit quality in the Ñuble Region, Chile. The experimental design was completely randomized blocks with two water treatments: irrigated and non-irrigated. Canopy temperature, soil moisture, xylem water potential (Ψx), fruit yield and fruit quality were evaluated. The results showed significant differences between the treatments and a moderate positive correlation between xylem water potential and CWSI (R2 = 0.67). Fruit yield and quality showed significant differences between the treatments; the non-irrigated treatment presented a decrease in size and yield, but an increase in the amount of total soluble solids. The CWSI was not a good indicator of plant water status, fruit yield or fruit quality in ‘Royal Gala’ apples.

Key words: xilematic hydric potential, apple, yield, fruit size, quality, thermic chamber, soil humidity.

¹ Facultad de Agronomía, Universidad de Concepción, Casilla 537, Chillán, Chile.

² Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Quilamapu, Casilla 426, Chillán, Chile.

^*Autor para correspondencia Email: cequezad@udec.cl