THE EFFECTS OF VARIETIES, PHOSPHORUS AND STAGE OF GROWTH AT APPLICATION ON THE TOLERANCE OF COWPEA (Viqna unquiculata (L.) Walp.) TO NORFLURAZON

  • : Ms Word Format
  • : 76 Pages
  • : ₦3,000 | $25 | ₵60 | Ksh 2720
  • : 1-5 Chapters
  •  
  • Click to DOWNLOAD Materials

THE EFFECTS OF VARIETIES, PHOSPHORUS AND STAGE OF GROWTH AT APPLICATION ON THE TOLERANCE OF COWPEA (Viqna unquiculata (L.) Walp.) TO NORFLURAZON

Abstract:

Two greenhouse experiments and nine field trials were conducted on the Institute for Agricultural Research Farm, Samaru, between 1981 and 1982, to evaluate the effects of varieties, levels of phosphorus and stages of crop growth at the time of herbicide application on the tolerance of cowpea to norflurazon. The varietal response trials were conducted both in the greenhouse and in the field using four cowpea varieties namely Ife Brown, IAR/ACC.335, IAR/ACC.341 and IAR/ACC.355. The other two sets of trials were only conducted in the field using Cv Ife Brown. Phosphorus levels evaluated were 0, 40 and 80 kg P2 O5/ha while the stages of growth of crop at the time of application were pre-emergence, at emergence, three weeks after emergence and six weeks after emergence, Norflu razon was applied pre-emergence at the rates of 0, 0.2, 0.4 and 0.8 kg a.i./ha in the varietal and phosphorus trials. Rates of 0, 0.4, 0.8 and 1.2 kg a.i./ha were used in the growth stage trial. Norflurazon at the rates of 0.4 kg a.i./ha and above in both the greenhouse and field trials resulted in cowpea leaf chlorosis irrespective of crop variety, phosphorus level or stage of crop growth of crop at the time of application. Reduction in leaf and root dry matter production was observed although the toxicity of the herbicide was more severe in the greenhouse. The cowpea varieties used responded differentially to the herbicide treatments as reflected especially in leaf dry weight in the greenhouse and shoot dry matter production in the field, with varieties ACC.355 and Ife Brown exhibiting more tolerance in the greenhouse and field respectively. However, in most cases the interactions between the herbicide rates and cowpea varieties were not significant,, Norflurazon was more toxic at 0.8 kg a.i./ha than the lower rates. Increasing the level of applied phosphorus from 40 to 80 kg P2O5/ha did not result in added advantage on cowpea grain yields. Phosphorus application slightly obviated norflurazon toxicity on cowpea, especially at the rate of 0.8 kg a.i./ha. Norflurazon applied at emergence appeared to be more toxic to cowpea than when applied at any other stage of growth although the effect was non-significant. However, the crop tolerated up to 0.4 kg a.i./ha of the herbicide irrespective of stage of growth

THE EFFECTS OF VARIETIES, PHOSPHORUS AND STAGE OF GROWTH AT APPLICATION ON THE TOLERANCE OF COWPEA (Viqna unquiculata (L.) Walp.) TO NORFLURAZON

Sharing is caring!

Leave a Reply

shares