Abstract

The integrated effects of weather change (Global warming), genotypic factors and cultivars on the growth and productivity of cassava (Manihot esculenta Crantz)were investigated in South-eastern Nigeria in 1999/2000 and 2000/2001 cropping seasons. Plant height (m), number of roots and fresh root yields (t/ha) differed among the seasons in response to global warming and were dependent on a combined optimum rate of each individual treatment. The optimum plant height (m) obtained during the two seasons ranged from 2.0 to 2.1 M and were obtained by the interaction of TMS 30572 x 750 kg/ha stake weight  x 3 shoots per stand. The highest fresh root yield of 28.0 and 13.6 t/ha were obtained by the interaction of cultivar NR 8082 x 875 kg stake weight x 3 shoots per stand. The combined analysis of variance for fresh root yields showed significant (P = 0.05) mean squares for cultivar, stake weight, number of shoots per stand and seasons (years). There was cultivar x stake weight x number of shoot x season interaction, indicating that the yields of the treatments responded differently relative to each other in different years. Higher plant height (2.1 m) and fresh root yield (28.0 t/ha) were obtained in 1999/2000 than in 2000/2001(1.9 m and 13.6 t/ha). Crop factors and weather change tremendously determined growth and productivity of cassava in Nigeria. Crop factors and weather were responsible for the variations in cassava yields in Nigeria.

Key words: Cassava, productivity, climatic factor, south eastern Nigeria, cultivars.