Fruit quality in 'Nijisseiki' Asian pear under deficit irrigation: Physical attributes, sugar and mineral content, and development of flesh spot decay

Responses of Asian pear (Pyrus serotina Rehd. 'Nijisseiki') to water stress were studied to obtain information that may be useful in irrigation management. Stress was applied to plants, by replacing 50% of their evapotranspiration (ET) loss, at either of two stages of growth. Stage 1 (early stress) coincided with slow fruit growth and rapid vegetative growth and Stage 2 (late stress) was from 3 weeks before harvest. Fruit water potential decreased in stressed treatments compared to the control. Osmotic adjustment occurred only in early-stressed fruit. Fruit concentration of N, P, K, Ca, and Mg decreased during the early stress period. Water stress did not affect the concentration of N, P, K, and Mg in fruit, but tended to reduce Ca in early-stressed fruit. The latter had a higher concentration of sucrose, glucose, fructose, and sorbitol than non-stressed fruit after 35 days treatment. There was no consistent effect in late-stressed fruit. Water stress did not influence fruit yield, size, or soluble solids. Fruit weight was significantly reduced in the late-stress treatment compared with the control. Early-stressed fruit tended to have higher flesh spot decay although it was reduced in the late-stress treatment.