Objective Using the nut of Juglans regia and Juglans sigillata in Liangshan of Sichuan as samples to study the phenotype abundance and variation characteristics for detecting resource and providing theory evidence in using resource reasonable.
Method Taking 330 seedlings from 15 J. regia and J. sigillata populations as research materials, the diversity and cluster analysis were studied using 18 nut phenotypic traits.
Result (1) The coefficient of variation of phenotypic traits in Liangshan walnut population originated from seedlings was between 8.46% and 59.47%, with an average of 35.26%. The nuts with very large (> 20.0 g) and very small (< 5.0 g) single nut weight occupied a certain proportion. The phenotypic traits meet almost all the trait descriptions in the "Guidelines for the conduct of tests for distinctness, uniformity and stability-Juglans (Juglans L.)". Three features in shape and one in skin color of kernels were added. The Simpson index of population genetic traits was 0.201-0.855, Shannon-Wiener index was between 0.649 and 2.873, indicating abundant variations in nut phenotypic diversity in this area. (2) The phenotypic differentiation of 18 phenotypic traits in populations was larger than that among populations in this area and the differentiation coefficients among populations was 6.03%, suggesting the phenotypic differentiation in populations was the main variation source. (3) UPGMA cluster analysis showed that the Manhattan distance of nut phenotypic traits were positively related to the geographic distance or climatic conditions.
Conclusion The nut phenotype of J. regia and J. sigillata in Liangshan was abundant. It is the important area for distribution of diversity walnut resources in China.
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