Five early maturing pigeonpea (Cajanus cajan) genotypes; ICPL 146 1985HK, ICPL 87 Isolation (85K), ICPL 85010, ICPL 85024 and ICPL 8304 were evaluated in a growth chamber study and in a greenhouse/outdoor study. Genotypes grown in growth chanter at 25/15°C, day/night with 14 hour photoperid and light intensity of 480 μEm-2sec-1, produced 5-7 main stem branches within the first 7 weeks and flowerd within 54-65 days. Those grown at the same conditions but with 10°C night temperature produced only 1-4 branches in the same period and flowered between 65 and 79 days. Plants grown in the greenhouse in the fall when photoperiod was 13½ hours, and temperature ranged from 31-42°C during day and 9-18°C during night flowered in 55 to 65 days. These plants grew faster than those started outdoors, where average weekly temperature was below 10°C for 4 of the 5 weeks before their transferal to the greenhouse and eventual flowering between 75 and 94 days. Some outdoor seedlings experienced epicotyl damage by a -1°C cold and these initiated shoots from axillary buds on underground nodes and flowered within 98–101 days.