LINEAR THINNING IN A CLONAL TEST OF <em>EUCALYPTUS</em> <em>CAMALDULENSIS</em> FOR CONVERSION TO A CLONAL SEED ORCHARD

Abstract

VARGHESE, M., LINDGREN, D. & RAVI, N. 2006. Linear thinning in a clonal test of Eucalyptus
camaldulensis for conversion to a clonal seed orchard. In this study, we used linear deployment technique
to carry out genetic thinning of clones and ramets in a three-year-old clonal test of Eucalyptus camaldulensis
for converting it to a seed orchard. Four different strategies, namely, truncation selection and three
linear thinning options, were employed to have a balanced representation of clones in the orchard.
Three linear strategies were considered, namely, to retain the same ramet number, to keep the gain same
or to keep the diversity same as with truncation selection. The gain and diversity that can be achieved
with the different options were studied using suitable intercept and slope values for the linear deployment
line. Linear deployment retaining the same ramet number was efficient in conserving diversity compared
with the second strategy of keeping genetic gain the same as truncation selection. The third strategy
which provided maximum gain at the same diversity as truncation selection was suggested to be the most
balanced method of thinning the orchard as it provided high gain and reasonable diversity and adequate
options for further thinning based on later observations including fertility. Simple mass selection for
height growth was as effective as the second linear strategy in terms of both genetic gain and diversity.