Relationship of Cassava Growth Parameters with Yield, Yield Related Components and Harvest Time in Ibadan, Southwestern Nigeria

Abstract

The relationship of major growth parameters with yield at various times of harvesting of cassava was investigated during 2007 and 2010 in a tropical Alfisol in Ibadan, Nigeria. Cassava (TMS 30572 and TMS 92/0326) was planted at 1m x 1m (10,000 plants per hectare) and fertilizer (NPK 15-15-15 and organomineral fertilizers) applied at planting using a split-plot arrangement in a randomized complete block design (RCBD) with three replicates. Parameters assessed include plant height, number of leaves, leaf area index (LAI) up to 6 Months After Planting (MAP), fresh and dry root yield, shoot yield, number of roots and harvest index at harvest  at 9, 12, 15 and 18 MAP.  The LAI at 2-6 MAP in 2007 and 4-6 in 2008 contributed significantly to the root yield while plant height at 1 MAP exhibited a negative relationship with fresh root yield of cassava within the same period (r=0.47(n=37)p= ≤ 0.05). Root dry yield was positively correlated with fresh root yield (r=0.46(n=37) p= ≤ 0.05, in 2009) Plant growth parameters at 4-6 MAP all contributed to increased fresh root yield at 12 MAP harvest. Growth parameters at various stages had  negative relationship with root yield at 18 MAP harvest. This delay made extra demand for assimilates partitioned in favour of the cassava shoot growth. Cassava should be harvested between 12-15 MAP; delaying harvest beyond this age did not result in significant addition to the root yield, instead, promoted bacterial rot especially in TMS 92/0326 cassava variety.

Keywords: Growth parameters, Yield, Correlation coefficient, Months after planting