For this project, physiological maturity was defined as 225 heat units (approximately 12–17 d) after observed R7 for M-206 and 300 heat units (approximately 15–20 d) for CXL745 (Counce et al.,2015). Heat units were determined using ORYZA’s hourly approximation technique (see Bouman et al., 2001 for further detail). Since R7 typically occurs roughly 15 d following 50% heading, this definition of physiological maturity coincides with the general guideline that physiological maturity falls 35–40 d after 50% heading for most rice varieties (IRRI, 2013). Sensitivity of simulated yields to this definition of physiological maturity is addressed in a following section For the southern-most CA site, R7 was not observed and the date