Effects of Plant Population and Water Stress on Yield of Selected Maize Varieties in Mwea and Bura in Kenya

Abstract

Maize (Zea mays L.) is currently a very crucial food source with over 1 X 109 tons being produced across the world, since 2013. It is Kenya’s main food security crop with an annual demand of 3.6 million metric tons. The crop’s productivity has been declining over the years partly due to inappropriate plant population densities by farmers, and water stress. Recent intense droughts have resulted to significantly reduced maize growth and consequently its grain yield. A study was conducted in the period December 2018 to April 2019 in Mwea Irrigation scheme in Kirinyaga County, and Bura Irrigation scheme in Tana River County. The objectives of the study were to determine the effects of plant population and water stress on growth, yield and yield components of selected maize varieties, in Mwea and Bura Irrigation Schemes, respectively. Experimental plots were set up in a randomized complete block design, in a split-split plot arrangement. Pioneer (PHB30D79), DH04, SC Sungura 301, SC Duma 413 and DH02 maize varieties were planted at treatment plant population of 53,333, 66,666 and 88,888 plants ha-1, respectively, under water stressed and well-watered conditions. Water stressed treatment was applied at the tasseling growth stage of maize (55-days after sowing) until physiological maturity. Data collected included: length of cob, height of ear from the soil level, plant height at maturity, above ground biomass, and grain yield. Data was analyzed using analysis of variance (ANOVA) and the means were separated using the least significant difference (LSD) test at P=0.05. The results showed that when plant population was increased, the growth parameters measured and grain yield of maize decreased significantly. The study established that the recommended population density for the study areas as 53,333 plants per hectare. The maize variety Pioneer (PHB30D79) grown at plant population of 53,333 plants ha-1 produced significantly more grain yield than all other maize variety against plant population interaction treatments. Plant population and water stress are important constraints limiting the productivity of maize. Water stress during the reproductive stage of maize significantly reduced its grain yield and yield components.