Six pine trees were mated using a half-diallel mating design. There were no selfs or reciprocals in the mating. Pines are monoecious species, meaning that male (pollen catkins) and female (strobili) reproductive organs are found on the same tree. A tree can be used as male, female or both in the mating. One of the parental combinations was not made, so the half diallel was not complete. In total, 14 crosses (full-sib families) were obtained. The field experimental design was a randomized complete block design in which the experimental unit was a plot containing on average 4.3 trees per full-sib family. The experiment was replicated in four locations and there were six blocks per location. Wood density of trees was measured at age 10. The first five observations of the data set (in file ‘diallel.csv’) are given below: