Potential and realized yield in pearl millet (Pennisetum americanum) as influenced by plant population density and life-cycle duration

Abstract

A single hybrid of pearl millet, 841A×J104, was grown at four plant populations covering the range 2–20 plants m−2 under 13.5 or 15.5-h photoperiods during the vegetative phase (emergence to floral initiation) to effect a short (75-day) or long (90-day) crop duration, respectively. The effect of these treatments on tiller production, leaf-area production, dry-matter accumulation and grain-yield is described, and the relationship between radiation interception (Qi) during the phase from floral initiation to flowerng (GS2), and number of grains (yield potential) and grain-yield is examined. The treatments caused significant variation in tiller and leaf-area production, radiation interception and numbers of grains per unit area at maturity. Number of grains, which ranged from 37 to 71×103 m−2, was correlated (r2=0.83) with intercepted radiation during GS2. Thus at high plant population in the long ncrop-duration treatment, where leaf area was highest during GS2, number of grains was greatest. Grain-yield less strongly correlated (r2=0.63) with intercepted radiation during GS2 because, in crops with many grains, grain-size was reduced. Possible reasons for reduced grain-size in crops with high yield-potential are discussed