water in the well-watered range. The dry down treatment was conducted by controlling soil water to be reduced ≤30 ml every day so that the drying cycle extended over two weeks. This controlled dry down helped to ensure that the drying cycle did not advance too quickly for precise measurements of the point at which transpiration began to decline. The daily ET of each pot was calculated by subtracting the pot weight measured on the current day (Wtdaily) from the combined weight on the previous day of the pot and added water. When ET under dry down declined below 10% of the control, the final weight of the pot (Wtfinal) was determined as the lower limit of extractable soil water as described by Sinclair and Ludlow (1986) and Miller (2000), which was also recorded as the endpoint. In addition, the number of days to reach the endpoint was recorded. For each pot under dry down, total transpirable soil water (TTSW) was determined based on the difference between upper and lower limits of extractable soil water. Daily FTSW was obtained following Eq. (1). Transpiration ratio (TR) and normalized transpiration ratio (NTR) were determined following Eqs. (2) and (3), respectively, where ETdry is ET under dry down conditions and ETck is ET under well-watered conditions. For the pots receiving dry down treatment, supplemental water consumption (SWC), expressed as the percentage of water added back to each dry down pot over the drying cycle relative to TTSW, was also calculated. This value represents the actual water consumption for each genotype and cultivar during dry down in this study.