Leaf Area Development and Dry Matter Production of Cassava

Abstract

AbstractMost published work on cassava (Manihot esculenta Crantz) plant growth and yield responses to environment has been conducted at high latitudes. Little is known of cassava responses to environment when grown at lower latitudes. A field experiment was conducted in Hawaii (21°N lat) during 1986 summer and 1987 winter to study leaf area development and efficiency of dry matter partitioning of cassava when grown under seasonal regimes of temperature and solar radiation. Plants were grown under optimum moisture and nutritional conditions. A series of biomass harvests were collected throughout the growing season to examine effects of temperature and solar radiation on leaf area index (LAI), top and root dry yield, and dry matter partitioning. Maximum LA1 values of about eight and six were attained by 240 d after planting (DAP) in summer and winter, respectively; maximum root growth rates of 17.1 and 13.5 g m−2 d−1 were attained at 240 and 300 DAP in summer and winter. Dry matter partitioning to roots had little seasonal variation and increased with plant age; dry matter partitioning to branches was more sensitive to environment and substantially increased during the summer months. Overall, leaf and root growth proceeded almost similarly in both summer and winter; differences in root yield between seasons were largely determined by differences in dry matter allocation to branches.