Agromorphological Performance and Character Association of Finger Millet under Varying Phosphorus Regimes

Abstract

Finger millet production on more than 30% of world arable land is limited by P availability and more than 70% in the semi-arid and marginalized areas which covers most of the Sub-Saharan Africa. Phosphorus is one of the most important elements significantly affecting plant growth and metabolism. Three finger millet varieties (U-15, P-224 and Ikhulule) were evaluated under four P fertilizer levels (0, 12.5, 25 and 37.5 kg ha^-1 P₂O₅) at the International Crops Research Institute for the Semi-Arid Tropics Station, Alupe and the Kenya Agricultural and Livestock Research Organization Station, Kakamega during the long and short rainy seasons of 2015 with the aim of determining their agromorphological response and trait associations. The on-station experiments were laid out in Randomized Complete Block Design in factorial arrangement with three replications. The statistical analysis of phosphorus levels and variety exhibited significant differences (P<0.05) to stand vigor, plant height, leaf blade length, number of leaves and lodging. The results revealed that application of 25 kg ha^-1 P₂O₅ rate led to the tallest plants (65.0 cm), longest leaf blades (58.0 cm) and highest number of leaves per plant (16) at Alupe site while 37.5 kg ha^-1 P₂O₅ rate eliciting the tallest plants (58.79 cm), longest leaf blades (51.44 cm) and highest number of leaves per plant (13) at Kakamega site. The highest rate led to the greatest vigor in both sites for both seasons while the control had the poorest vigor. Variety P-224 showed the highest lodging count with 32 out of 246 plants per experimental unit during the rainy season at Kakamega. The unit increase in grain yield was positively and significantly correlated with increased values of the harvest index (r=0.375), number of leaves (r=0.393) and plant height (r=0.431) but negatively and significantly correlated to the 1000-grain mass (r=-0.578) and lodging (r=-0.233). The best phosphorus treatment for most of the parameters was 25 kg ha^-1 P₂O₅ at Alupe while maximum levels of the study parameters were realized under the 37.5 kg ha^-1 P₂O₅ rate at Kakamega.