GENETIC VARIATION IN EARLY GROWTH OF EUCALYPTUS SEEDLINGS UNDER MODERATE SOIL SALINITY CONDITIONS

Abstract

In the Central and Northern regions of México there are large areas of agricultural lands that are marginal due to drought and moderate salinity. These lands can be used for commercial forest tree plantations with fast growing species adapted to such soil conditions. In order to identify genotypes with greater potential for adaptation to salinity, the genetic variation in growth rate and biomass production of seven-month-old Eucalyptus camaldulensis Dehnh. plants from 42 open-pollinated families was evaluated after four months of exposure to two soil salinity levels (3.47 and 5.15 mmhos cm-1). Growth of plants was not affected by salinity levels, but a significant variation was found among families. Variance among families accounted for 5 to 10 % of total phenotypic variance in most traits. Plant height, stem diameter, and total plant biomass showed moderate heritabilities both at the individual (h2 i >0.38) and family-mean (h2 f >0.67) level, indicating a favorable response to selection in these conditions. Moreover, genetic correlation among these traits was higher than 0.85, so any of them might be used as a criterion for early selection in this population.