Growth analysis of the Pennisetum purpureum cv. Cuba CT- 115 in the biomass bank technology

Abstract

To study the performance of some growth indexes of Pennisetum purpureum cv. Cuba CT ? 115, when it is used as biomass bank, it was applied a completely randomized sampling design, with 15 repetitions, (bunches as experimental unit) .The treatments consisted on the regrowth age or grass rest . The culture growth rate (CGR), the net assimilation rate (NAR) and the specific foliar area (SFA) were determined to describe the growing of this cultivar. The culture growth rate was characterized, generally, by its gradual increase from 15 days, to get the maximum growth rate that was specific for each cycle and, from that moment on, began to decrease. The maximum productivity during the first year was reached at 71, 57 and 61 days of re-growth for cycles one, two and four, respectively. In the second year, it was obtained at 86, 46, 45, and 69 days of re-growth for cycles one, two, three and five, respectively. The specific foliar area did not vary in the first rest cycle with age in the first year, and decreased in the remaining cycles. The net assimilation rate shows specificity in its response pattern to the re-growth age in each rest cycle. It is concluded that CGR, SFA and NAR had specific response for each cycle, regarding the re-growth age and the climatic characteristics, and showed to be adequate indicators for the analysis of the growing of Cuba CT-115 cultivar. It is recommended the use of growth indexes of this grass as a tool for the management of biomass banks, as well as its utilization in the studies of other species of Pennisetum genre and in the design of other? management options.
Key words: grass, growth indexes, culture growth rate, net assimilation rate, specific foliar area