Purpose To determine the genetic diversity of inflorescence phenotypic traits of Macadamia spp., providing a foundation for the protection and utilization of germplasm resources.
Methods The phenotypic traits of 14 inflorescences of 91 Macadamia spp. germplasm resources were analyzed and evaluated by coefficient of variation, Shannon-Wiener diversity index, correlation analysis, principal component analysis, cluster analysis and stepwise regression analysis.
Results 1) The genetic diversity index of four quality traits was 0.120 9-1.645 8; the genetic diversity index of ten quantitative traits was 1.864 1-2.074 6, and the coefficient of variation of ten quantitative traits ranged from 10.09% to 28.24%. 2) Correlation analysis among quantitative traits showed that the correlation of 22 pairs of traits was extremely significant (P<0.01), and that of eight pairs of traits was significant (P<0.05), which was close and complex. 3) Five principal components with characteristic values greater than one were screened out by principal component analysis, and the cumulative contribution rate reached 75.525%, reflecting most of the information of inflorescence phenotypic traits in Macadamia spp. germplasm. 4) Cluster analysis divided the germplasm resources into four groups when the genetic distance was 15. 5) Based on the weight of principal component contribution rate, a comprehensive evaluation function was constructed by fuzzy membership function: F=0.356F1+0.213F2+0.192F3+0.129F4+0.109F5. The comprehensive scores (F-value) of 91 Macadamia spp. germplasm resources ranged from 0.508 to 2.640, and the top five germplasm were D4, HAES695, YN55, Guang9, and YN68.
Conclusion The inflorescence phenotypes of Macadamia spp. germplasm resources show rich genetic diversity. Based on the comprehensive evaluation of phenotypic traits, five individual plant resources with better traits are selected.
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