Biomass Production and Water Economy of Sugarcane and Energy Cane Genotypes Grown in Water-Deficient and Well-Watered Regimes

Aims: Study designed to characterize water economy and biomass production of sugarcane and energy cane genotypes grown in a rain-shelter under well-watered and water-stressed conditions during plant cane and two consecutive ratoon cane phases.

Study Design: Randomized complete block with 5 replications.

Place and Duration of Study: Texas A&M AgriLife Research and Extension Center near Corpus Christi during 2015 and early 2016.

Methodology: Stem cuts of sugarcane line TCP94-5753 and energy cane lines TUS56 and TUS59 were hand-planted in pots. There were three phases including a water-stressed initial plant cane phase and two sequential well-watered ratoon cane phases. Daily whole-plant transpiration was calculated from hourly pot weight changes measured by electronic loadcells. At the end of each phase, plants were harvested to determine above-ground biomass, partitioned into dry leaf blades biomass and stem dry biomass.

Results: No differences in above-ground dry biomass production or water economy among genotypes after the water-stressed plant cane or the first ratoon cane phase, but TUS56 and TUS59 produced 2.32 and 1.83 times more tillers than the sugarcane genotype, respectively. Cumulative transpiration of TUS56 at the end of this first ratoon cane phase was 17% higher than that of TUS59 and TCP94-5753. At the end of the second ratoon cane phase, total above-ground dry biomass were 60% higher in TUS56 than in the sugarcane genotype, but not different from those in TUS59. Cumulative whole-plant transpiration during this phase was about 88% higher for the energy cane genotypes.

Conclusion: Genotypes performed equally in above-ground biomass production and water economy after exposure to water deficits during the initial plant cane phase. No differences in biomass production were observed after the well-watered first ratoon cane phase among genotypes, but TUS56 exhibited more leafiness and transpired more than TUS59 and the sugarcane genotype, and both energy cane lines produced more tillers than the sugarcane.