Abstract:

The silique shattering resistance index (SSRI) of 229 accessions (Brassica napus L.) was investigated through random impact test (RIT) for screening silique shattering (SS) resistance. The accessions displayed wide variation in SSRI, which ranged from 0.000 to 0.7675 with the variance coefficient (CV) of 114.4%. Only two varieties (accounting for 0.9%) showed SS resistance; about 3.93% of the varieties (lines) showed relative resistance to SS; and about 8.73% were identified as the medium. Most (59.38%) of the varieties (lines) were identified as very susceptible germplasm to SS, and 27.07% as the susceptible germplasm. According to independent experiments in three years with 6 representative varieties (lines), the SSRI was dominated by genetic factor with obvious interactions with environment, and the RIT showed stable results within years. The simple correlation analysis showed that the SSRI had significant (P<0.01) negative correlation with silique number per centimeter, and significant (P<0.01) positive correlations with silique wall thickness, silique length, silique width, beak length, and seed number per silique. However, the correlation coefficients (CV) were rather small indicating the selection potential of varieties with high SSRI and fine silique traits via recombination in B. napus breeding programs.

Key words: Brassica napus L., Silique shattering resistance, Variety screening