Comparative analysis of test guidelines for distinctness, uniformity and stability of grapevine (Vitis L.) formulated by China, UPOV and Japan

Abstract:New varieties are an important factor in promoting the development of the fruit industry. Application of plant distinctness, uniformity and stability (DUS) test is the technical basis for new variety protection and for variety certification. DUS test guidelines are the technical standards to guide the testing units to carry out DUS testing work, and also the technical specifications for the examination and approval authorities to carry out the substantive examination of new varieties. This paper analyzes the differences in propagation materials, test methods, assessment of distinctness, uniformity and stability, test traits and other aspects among the DUS test guidelines released by China, UPOV (International Union for the Protection of New Varieties of Plants) and Japan for grape varieties, and provides a reference for improving our country’s DUS test guidelines for grape varieties. UPOV published the Grape DUS Test Guidelines TG/50/9 in 2008. The DUS test guidelines for grape varieties in Japan were coded as 1654. In 2014, China released the grape DUS test guidelines, NY/T 2563. The quality requirements for propagating material specified in the three guidelines are basically the same: strong stems, with full vitality, full buds, and no pests and diseases. In view of the many ways of grape propagation, which include sexual reproduction and asexual reproduction such as cuttings, grafting, and layering, the three guidelines require submission of propagation materials in the form of self-roots seedlings, grafted seedlings or cuttings. In addition, the three guidelines have different requirements for the number of submis-sions. For TG/50/9, the minimum number of materials required to be submitted is 5. In the case that the root of a variety is sensitive to phylloxera, it is allowed that scions of the cultivar can be grafted onto a specific rootstock variety that is not sensitive to the pest, and that the submission of propagation material is sufficient to produce 10 grafted seedlings or 10 self- rooting seedlings. 1654 requires 7 seedlings submitted. NY/T 2563 requires no less than 10 self-roots seedlings submitted or at least 50 buds when cuttings are submitted. The three test guidelines have the same requirements for test cycles, and each requires results of at least two independent growth cycles. Traits are the basis for DUS test review to accurately identify, distinguish, and characterize plant characteristics or traits that can be heritably expressed. Tested traits are divided into 5 categories according to function and requirements, including traits under standard test guidelines, asterisked (*) traits, grouping traits, additional traits and technical questionnaire characteristics. TG/50/9 has 44 tested traits, including 2 qualitative traits, 35 quantitative traits, and 7 pseudo-qualitative traits. NY/T 2563 has 51 tested traits, including 3 qualitative traits, 33 quantitative traits, and 15 pseudo- qualitative traits. 1654 has 52 tested traits, including 2 qualitative traits, 40 quantitative traits, and 10 pseudo- qualitative traits. Through the comparison of the tested traits, it can be found that there are 22 common traits in TG/50/9, NY/T 2563 and 1654 test traits, 10 with different grades, 3 with different expression states, 5 with different characteristic types, 1 with different observation sites, 2 with different grades and characteristic types, and 1 characteristic with different expression states and characteristic types. There are 44 basic traits in TG/50/9, 28 in NY/T 2563, and 52 in 1654. There are 28 TG/50/, NY/T 2563 and 1654 asterisked characteristics. TG/50/9 has 11 grouping traits, NY/T 2563 has 7, and 1654 has 11. The traits of the three test guidelines are comprehensively analyzed, and the test traits can be summarized into 6 categories: bud traits, branch traits, leaf traits, flower traits, fruit traits, and seed traits, of which leaf and fruit traits are the majority, accounting for 32.69%-39.22% and 29.55%-34.62% of all test characteristics, respectively. Through analysis and comparison, it is found that the three are basically the same in terms of the quality and form requirements, test cycle, test locations, additional tests, asterisked traits and other aspects of the submission of propagating materials, while the requirements for the number of reproducing materials submitted, DUS determination standards, test traits, basic traits, grouping traits, selective test traits, technical questionnaire traits, etc. are not the same. With the country’s increasing emphasis on plant intellectual property protection and stable support for breeding of new varieties, the number of varieties bred in China is increasing, and more than 30 grape varieties are reported and registered every year. It is very important to speed up the revision of the grape variety test guidelines. Therefore, the authors put forward 11 revision suggestions in order to provide a strong guarantee for the breeding and protection of grape varieties in China, in line with the international grape DUS test guidelines while combining field practice.