Estimation of the Genome Sizes of Six Walnut Varieties by Flow Cytometry

PurposeTo estimate and compare the genome sizes of six walnut varieties by flow cytometry and provide a reference for the study on the genetics, genomics and chemistry of Juglans L. plants.

MethodFresh leaves of six walnut varieties including Juglans sigillata Dode, J. sigillata cv. Yangbi, J. sigillata cv. Santai, J. sigillata cv. Yunxinyunlin, J. regia Linn and J. regia cv. Chandler were taken as samples, and Oryza sativa ssp. japonica with known genome was set as the standard. The C values content of DNA of all the six walnut varieties were detected by flow cytometry (FCM) and the genome sizes were calculated according to the the genome size of O. sativa L. ssp. japonica.

ResultThe genome sizes of J. sigillata, J. sigillata cv. Yangbi, J. sigillata cv. Santai, J. sigillata cv. Yunxinyunlin, J. regia and J. regia cv. Chandler were (543.2±35.7) Mb, (548.8±43.1) Mb, (554.4±14.5) Mb, (548.8±14.7) Mb, (551.6±39.0) Mb and (520.8±38.5) Mb, respectively. And there was no significant difference between the genome size of these six walnut varieties (P>0.05).

ConclusionThe species differentiation, domestication and interspecific hybridization of Sect. 1. Juglans plants didn’t induce variation of genome size. What’s more, the first report of the genome sizes of J. sigillata, J. sigillata cv. Yangbi, J. sigillata cv. Santai and J. sigillata cv. Yunxinyunlin would provide useful data for the further research on the endemic species of China J. sigillata, and enrich the C value database of Juglans L. plants.