Radiata Breeding

Abstract

Thulin (NZ For Serv Tech Pap 22, 1957) reported the initial development of radiata breeding, with intensive plus-tree selection and two grafted clonal orchards. Shelbourne et al. (Variation, inheritance and correlation amongst growth, morphological and wood characters in radiata pine, 1972) looked at genetic correlations and heritabilities of most traits in 12-year-old OP radiata at three sites. CP results from 1957 were the first solid ‘good news’ of the breeding programme. Wilcox et al.’s report on CP progeny showed mainly additive variance for height and other traits at age 5. Assessment of the 588 OP progenies, planted 1969, facilitated backward selection to create a 1.5 generation orchard. The selection of the best offspring and their control mating was only used to backward select their parents, not for AS to advance the breeding population. Selection among the 588 OP families was later made at age 11, and OP tests were planted of these second-generation selections. In the 1986 Development Plan, a new breeding population from within-family selection was planned, still using backward selected parents for crossing. The families created formed the foundation for the RPBC’s OP testing and a new cloned breeding population. Rosvall et al. in a stochastic simulation of gains from within-family clonal selection over ten generations showed a model that could well be followed for radiata.