Comparisons of Selected and Cloned Plantlets against Seedlings for Rehabilitation of Saline and Waterlogged Discharge Zones in Australian Agricultural Catchments

Abstract

Clonal lines of Australian tree species have been developed for tolerance to saline and/or waterlogged conditions. These clonal plants have been shown to be more tolerant under glasshouse and field conditions when compared with seedling lines. Selection procedures included the initial collection of seed from trees growing naturally in seasonally waterlogged and/or saline soils. Following germination and establishment, three-month-old seedlings were stressed in glasshouse trials using progressively increased levels of salinity, either in freely drained or saturated conditions, and the most tolerant individuals were micropropagated. Under conditions of saturation and salinity stress, in both glasshouse trial conditions and under field situations, selected and cloned Eucalyptus cawaldulensis. E. spathulata subspecies spathulata, Casuarina obesa and C. glauca plants showed higher survival rates and the surviving plants grew faster than provenance-matched seedlings.