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Rhus succedanea L. is cultivated in Japan for the wax that can be extracted from its fruits. We determined genetic data for specific traits associated with wax production (fruit number per cluster, FN, fruit weight, FW, number of clusters per area, CN, and wax content, WC) in five traditional cultivars and 13 newer clones. Data were collected over 4 years and alternate bearing was observed: 2001 and 2003 were years with high yields; in 2002 and 2004 yields were poor. The restricted maximum likelihood method was used to calculate (co)variance components for analysis. Broad sense heritability was estimated and ranged from low (FN and CN) to high (FW and WC) for the traits examined. There were positive genetic correlations between FW and WC and negative ones between FN and FW throughout the 4 years. Genetic correlations between CN and the other traits were positive in good crop years and negative in bad crop years. For each assessed clone, the four traits in the 4 years were evaluated using best linear unbiased predictors (BLUP) of the clonal breeding values. The BLUP scores for both FW and WC exhibited positive correlations between pairs of years, whereas there were positive BLUP correlations for CN when the high yield and low yield years were examined separately. The traditional cultivars and the newer clones were also characterized. Some of the clones were better than the traditional cultivars with regard to wax yield and reliability of production. The trait characteristics and the future breeding are discussed. [ABSTRACT FROM AUTHOR]

Focuses on Cryptomeria japonica D. Don (sugi) as one of the most important forest tree species in Japan. The progeny of a cross between the cultivars Iwao-sugi and Boka-sugi were analyzed using RAPD markers, with the pseudo-test-cross strategy, to construct linkage maps of the parental cultivars. A total of 355 segregating loci were detected among 72 offspring: 200 and 155 markers being distributed in Iwao-sugi and Boka-sugi, respectively. In Iwao-sugi, 119 markers with confirmed map positions were assigned to 21 linkage groups covering 1756.4 cM. In Boka-sugi, 84 markers with confirmed map positions were assigned to 14 linkage groups covering 1111.9 cM. The framework map distance in Iwao-sugi and Boka-sugi provides about 62 and 40 percent coverage, respectively, of the total genome, estimated to be approximately 2800 cM in length. Using genetic linkage maps constructed in this study, 15 QTLs were detected that are associated with the modulus of elasticity (MOE), an important indicator of wood strength. The QTLs for MOE explained about 45 percent of its total phenotypic variance. Some QTLs associated with different phenotypic traits were located on the same linkage groups. Some of the QTLs for MOE measured by two different methods (the hanging method and the tapping method) were located independently on the different linkage groups.