To explore the economical and efficient selenium biofortification technology
for Chinese yam, a selenium biofortification field experiment of “Gui-Huai 7” and
“Ziyu Huai Shan” was carried out in Ganxu Town, Wuming County, Nanning. At
the early stage,expansion stage and maturity stage of tuber formation, different
amounts of selenium was applied by root and foliar fertilization to two varieties of
Chinese yam to study the effects of variety, fertilization method, time and amount on
selenium accumulation of Chinese yam. The results showed that the biofortification
effect of lower root selenium fertilization in early stage of tuber formation was the
best in the experiment. The selenium content in Chinese yam was up to 193.4 ± 21.3
μg/kg, which was 4.5 times that of the control group. The biofortification effect of
higher foliar selenium fertilization in early stage of tuber formation was the best. The selenium content of Chinese yam was up to 285.4±39.9 μg/kg, which was 6.6 times
higher than the control group. Different variety of Chinese yam had different selenium
accumulation effects under the same treatment. The optimal fertilization time was
the early stage of tuber formation in both foliar and root fertilization. It is feasible to
realize selenium biofortification by foliar fertilization and root fertilization, however,
the biofortification effect of foliar fertilization is better than root fertilization.