Tolerance of Accessions of Glagah (Saccharum spontaneum) to Drought Stress and Their Accumulation of Proline

Abstract

Glagah (wild sugarcane, Saccharum spontaneum) is a perennial grass that grows well in marginal soils. It has a high carbohydrate and fibre content, making it suitable for ethanol production and the study industry. Thus, glagah has potential as a crop species in its own right and may also be used in sugarcane breeding programs. However, glagah germplasm has not been extensively utilised in breeding programs, especially in relation to improving drought tolerance. This study was performed to evaluate the effect of drought stress over an eight week period on plant height, stalk diameter, green leaf number and leaf proline content of eight, two month-old accessions of glagah to identify their drought tolerance and to determine whether proline accumulation can be used as a metabolic marker of drought tolerance. Accessions, BOT-53, BOT-54 and BOT-62, were the most tolerant and productive. Two patterns of proline accumulation were shown in drought-stressed plants. In four accessions, proline increased after both four and eight weeks of drought stress. While, in the others, proline increased after four weeks and then declined. Significant, positive correlations were found between leaf proline contents (after both two and eight weeks of drought) and plant height at all assessment times. A significant, positive correlation was also discovered between proline content after eight weeks and green leaf number after four weeks of drought. Glagah accessions of BOT-53, BOT-54 and BOT-62 show drought-tolerance and have potential for use as a crop for arid regions or in breeding programs to improve production of sugarcane. Drought tolerance in glagah appears to be mediated by proline and accumulation of this amino acid has potential as a metabolic marker of drought tolerance.