Preparation of the UPOV Guidelines for the Conduct of Tests for Distinctness, Uniformity and Stability–Tea Plant [Camellia sinensis (L.) O. Kuntze]

Distinctness, Uniformity and Stability （DUS） testing is the technical base of Plant Variety Protection （PVP） and the scientific basis for the approval of Plant Breeder＇s Rights （PBR）. DUS Test Guidelines are not only the technical manuals for the DUS testing authorities to conduct the testing, but also the technical standards for the competent authorities to examine the DUS of new varieties of plants. Tea plant, originated from Yunnan Province, China, is a very important woody cash species in the world. The International Union for the Protection of New Varieties of Plants （UPOV） DUS Test Guidelines for tea plant is the first Test Guidelines prepared by China for the UPOV. In this article, the subject, selection, and determination of characteristics, states of expression of characteristics and the selection of example varieties, assessment of the UPOV DUS Test Guidelines for tea plant were elucidated in detail. Finally, the proposal of PVP for tea plant in China was also proposed. The preparation of UPOV DUS Test Guidelines for tea plant will have important significance both for promoting the development of PVP and increasing the status of international PVP fields for China.

Surface potential uniformity and sensitivity of large-area PTFE electret discs of different thicknesses produced by a modified corona poling rotating system for dosimetry applications

In this study,large-area(6-cm diameter)Teflon polytetrafluoroethylene(PTFE)discs of different thicknesses(0.2-,0.5-and 1-mm)were negatively and positively charged by using the“modified single point-to-plane corona poling rotating system”.The effects of some crucial parameters of the PTFE disc as well as the modified corona poling rotating system on the PTFE surface potential uniformity such as.(a)PTFE disc thickness,(b)PTFE disc polarity and(c)needle-to-PTFE disc distance were successfully reported.Accordingly,closer needle-to-PTFE disc distance,positive charging mode and thinner PTFE disc provided a better PTFE surface potential uniformity.However,the effects of PTFE charge polarity and needle distance on the electrostatic charge potential uniformity were much more remarkable in comparison with the effects of PTFE thickness.Additionally,the surface potential distribution profiles of charged PTFE discs were totally flat and independent of the PTFE thickness at 5-and 13-mm needle distances for the negative and positive charging modes,respectively.At the optimized charging conditions,large-area PTFE electret disc(0.5-mm-thick)with positive uniform surface charge potential especially at the edges up to
1.8 kV with stability up to 77 days studied was produced by applying a new multiple heat treatment protocol to the PTFE disc for radon dosimetry.As also observed in this study,the sensitivity of PTFE electret dosimeters to a defined radon gas concentration increases as the PTFE thickness increases.Meanwhile,0.5-mm-thick PTFE electret disc produced was selected to be used as a high quality electret dosimeter with acceptable and superior parameters for different applications in particular medium-term radiation dosimetry in both low and high dose rate ionizing radiation fields.