Information on the effect of daylength on nonconverted and converted selections of sorghum is very limited. This study was designed to evaluate the effect ofdaylength on plant height (PHt), days to anthesis (DA), and other agronomic traits of local Millo Blanco nonconverted (MBNC) and three Millo Blanco converted (MBC) selections of forage sorghum (Sorghum bicolor (L.) Moench) and BTx406 (a 4-dwarf photoperiodinsensitive temperate grain sorghum used as the control) during an eight-month period in Puerto Rico. The MBC selections were based on approsirnately plant height of 50, 120 and 170 em. Plantings were made on the 21st day of each month from May through December, 1991. After an initial30-day growth period, plants were evaluated every 15 days until harvest. Days to anthesis of MBNC decreased from 175 (May planting) to 61 (October planting), then increased to 70 and 75 (November and December plantings, respectively). The mean plant height of MBNC followed a similar trend ranging from 278 em (August planting) to 138 em (November planting). Although a significant correlation was observed between days to anthesis and plant height in MBNC, the MBC selections and BTx406 (the control) were unaffected by planting date. Mean days to anthesis of the three MBC selections was similar throughout the year (61 days). This study demonstrated the possibility of making selections for height from converted sorghums prior to their formal release having by this wayan excellent opportunity for its utilization in a year round breeding program.