The effect of plant population density on growth and yield of maize
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Date
1990
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Abstract
Two maize varieties, Kawanzie, a short early-maturing variety and La Posta, a tall late-maturing variety, were sown on 10th April, in both 1986 and 1987, and 13th August, 1986 at 2.7, 5.4, 8.1, and 10.8 plants/m2 and at a rectangularity of 1:1, in a randoinised complete block design experiment at the Plantation Crops Farm of the Faculty of Agriculture, University of Science and Technology, Kumasi (6°43’N, 1°36’W), in the forest zone of Ghana.
The objective of the experiments was to study the effect of plant population density on the components of growth and yield of these varieties in the major and minor seasons in an attempt to explain observed seasonal differences in growth and yield of the varieties.
The results of the experiments showed that leaf and stem dry weights increased with increase in plant population density up to 8.1 plants/m2, after which the increase in plant density to 10. 8plants/m2 did not show any significant increase in both leaf and stem dry weights. The effect of plant density on the decline in leaf and stem dry weights showed no clear trend, except that the quantity of dry matter lost from both the leaves and stems were generally more with the increase in plant density for La Posta Stalk diameter decreased with increase in plant population density.
The results also showed that the components of growth: leaf area index and net assimilation rate, as well as total ear and grain yields and components were affected by both the date of sowing and plant population density. For early-maturing Kawanzie, grain yield and components increased in the major season up to 8.1plants/m2 and up to 5.4plants/m2 in the minor season and then declined. For the late-maturing La Posta however, grain yield and components were highest at 10.8plants/m2 in the major season, and the 8.1 plants/m2 treatment gave the highest grain yield in the minor season. The final grain yield for Kawanzie was higher in the minor seasons than in the major season, whilst, the reverse was obtained in the case of La Posta.
The results indicated that the number of ears per m4 increased as population density increased though the number of ears per plant and weight per ear decreased with increase in plant population density, showing that after the optimum densities for the two varieties and seasons, the number of plants/ma could not compensate for the decrease in yields and components.
Description
A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the award of the Degree of Master of Philosophy in Crop Physiology.