Guidelines for the conduct of tests for distinctness, uniformity and stability—Rape seed(Brassica napus L.)
1Key Takeaways
Technical requirements for variety specificity, consistency and stability testing of Brassica napus L. and general principles for result determination. Applicable to variety specificity, consistency and stability testing and result determination of Brassica napus L.
2Expert Interpretation
An in-depth interpretation of the technical requirements for testing the specificity (D), consistency (U) and stability (S) of Brassica napus varieties in the GB/T 19557.14-2017 standard, including core contents such as test cycle, trait observation methods, and judgment criteria, and an analysis of implementation points such as requirements for propagation materials and field trial design.
Standard Background and Technological Evolution
As the 14th part of the GB/T 19557 series of standards for testing new plant varieties, this standard inherits the framework of the UPOV international testing system and is locally adapted to the biological characteristics of Brassica napus. Compared with the 2004 edition, the 2017 edition has the following major revisions:
- Added quality trait tests such as glucosinolate content (trait 31)
- Refined the division of growth stages (Appendix B.1)
- Optimized the grading standards for quantitative traits
Core test requirements
| Test elements | Technical requirements | Judgment criteria |
|---|---|---|
| Specificity (D) | 2 growth cycle tests | At least 1 trait is significantly different from similar varieties |
| Consistency (U) | 200 samples of conventional varieties | Heteromorphic plants ≤ 7 plants (2% threshold) |
| Stability (S) | Intergenerational comparison | No significant variation in trait expression |
Key trait observation system
Grouped traits (UPOV important traits)
- Leaf lobes (trait 6): A qualitative trait that distinguishes the presence or absence of lobes
- Flowering period (trait 15): 9-level classification of very early (1) - very late (9)
- Total plant length (trait 24): The length of the main stem measured at maturity
Typical quality trait cases
5-level expression of petal color (trait 21):
1-white → 5-dark yellow (standard variety P194)
Quality control of propagation materials
| Indicators | Conventional varieties | Hybrid varieties | Detection standards |
|---|---|---|---|
| Clarity | ≥98% | ≥98% | GB/T 3543 series |
| Germination rate | ≥95% | ≥90% | |
| Water content | ≤9% | ||
Implementation suggestions
- Test design: Double replication, 100 plants/plot, row spacing 33-40cm
- Critical period management: Focus on the bud stage (code 50-59) and silique stage (code 70-89)
- Data recording: Strictly distinguish between group measurement (MG) and individual measurement (MS)
- Molecular assistance: Can be combined with NY/T 91 (erucic acid) and NY/T 1582 (glucosinolate) detection