Selection Of Oil Palm Materials With Higher Water Use Efficiency Using Carbon Isotope Discrimination

Carbon isotope discrimination (Delta) is a useful tool for screening planting material with higher water use efficiency (WUE). Growth, A and leaf gas exchange measurements were compared between five year-old clonal (PL68, PL 104, PL 106 and PL 127) and commercial, tenera, Dura x Pisifera (D x P) palms grown on peat. Leaf area index (LAI) and standing biomass in clone PL104 palms were greater by 35% and 54%, respectively than Dx P palms. Leaf gas exchange parameters such as photosynthetic rate (P-N), stomatal conductance (g(s)) and transpiration rate (T-r), were lower in clonal palms than D x P palms due to low soil moisture content especially in August 2012. However, there were no significant difference in P-N and g(s) between planting materials in February 2013. Subsequently, higher instantaneous WUE was found in clone PL106 palms with lower T-r, g(s) and intercellular CO2 concentration (c(i)) in February 2013. Clone PL106 palms had higher leaf Delta values (5.04%) than DxP palms. The Delta in leaf tissues was positively correlated with WUE. Clone with a higher WUE had the greater leaf Delta value. In contrast, leaf Delta was negatively correlated with the T-r, g(s) and ratio of intercellular CO2 concentration and ambient CO2 concentration (c(i)/c(a)). Our study suggested that selection for high WUE planting materials using Delta technique to provide greater value in oil palm breeding programs. PL106 was the most water use efficient material with better growth performance and could be a good potential planting material for areas prone to drought. (C) 2018 Friends Science Publishers