The main factors causing “imperfect shell development” (ISD) in thin-shelled walnut

Abstract

Effects of solar radiation, rainfall and cultivars on “imperfect shell development” (ISD) of the thin-shelled walnut were studied by means of field investigation and weather data comparison. The results showed that cultivars were the main factor causing the ISD of the thin-shelled walnut. Among the cultivars, Shangsong 6 was the most sensitive one, whose percentage of imperfect shell attained 67.3%, followed by Xiangling (52.7%). However, the rate of imperfect shells in Zhonglin 5 was only 20.9%. It was suggested that the main environmental factors contributing to the ISD of the thin-shelled walnut were sunlight intensity and rainfall during the shell-hardening stage.

Key words： walnut; shell; imperfect shell development (ISD)

Acknowledgements

This project was supported by the Key Technologies Research and Development Program of Hebei Province, China (No. 03230155D-2), and the Fund for Scientific Generals and Marshals of Agricultural University of Hebei, China.

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