Abstract

  The relationship between leaf senescence in cowpea [Vigna unguiculata (L) Walp.] and yield was studied in pot grown population of a local variety, kanannado. Treatments comprising of farm yard manure (single and double application), 200 ppm benzyl amino purine (BAP), 15% coconut milk (CM) and a combination of both manure and the hormones were also applied to determine their effects on senescence and yield. The experiment was carried out at the International Institute of Tropical Agriculture (I.I.T.A), Kano station, Nigeria. Chlorophyll level was increased by all the treatments with greater increase in the 200ppm BAP and 15% CM treated plants. The level of chlorophyll also decreased with increase in age of the cowpea plants. Senescence commenced earlier and progressed faster in the manure treated plants while it was significantly delayed by 200ppm BAP and 15% CM. Fodder and grain yields were greater in all the treated cowpea plants compared with the control. Interactive effects were observed in the combined treatments (manure +15% coconut milk and manure +200 ppm BAP) as chlorophyll  increased above that of manure and control plants. Also senescence process was delayed and yield was increased. The study suggests that leaf senescence in the photoperiod sensitive cowpea could be delayed by application of 200 ppm BAP, 15% CM and a combination of manure +15% CM and manure +200 ppm BAP and the delayed senescence resulted in increase in yield.

Key words: Farmyard manure, benzyl amino purine, coconut milk, leaf senescence, yield