Abstract
SUMMARY: Performance of Short Kaura, a photosensitive Nigerian sorghum, was compared at Samaru in ten sowings in 1972. Except for a two-week interval between the fifth and sixth sowings, all sowings were at weekly intervals from 12 May to 21 July. Total dry weight and grain yield decreased with delay in sowing after 26 May at the rate of 1700 kg.ha.−1 week−1 and 360 kg. ha.−1 week−1 respectively. Each week's delay in sowing after 12 May shortened the total growth cycle by 5·9 to 6·0 days, with 77 to 78 per cent in the vegetative phase, 7 to 8 per cent in the head development phase and 14 to 16 per cent in the grain filling phase. Although the date of head initiation seemed to be determined by photoperiod, sowing date also had a small but definite effect.