Abstract:

High seed vigor is the basis for plant establishment and determines high yield of crops in later stag?es. To better understand the genetic mechanism of seed vigor in rapeseed, a doubled haploid (DH) population con? sisting of 280 DH lines derived from cultivar Zhongshuang11 and a line R11 with contrasting germination potential was phenotyped using a seed germination vigor detection system. Four effective indicators of seed vigor, including the area under the germination curve (AUC), the mean germination time (MGT), the time taken for 50% seeds to ger? minate (T50), and the time between 16% to 84% germination (U8416), were assessed. The inheritance was analyzed by the Mixed Major Gene plus Polygene Inheritance model. The skewness and kurtosis analysis were also carried out. The results showed that AUC was controlled by 3 major genes and 9 minor polygenes, with overlapping effects. The heritability of the major genes was 74.88%, indicating the trait was less influenced by the environment. MGT and T50 were controlled by 2 major genes, and the number of polygenes with minor effects was 13 and 14, and the heritability of major genes was 64.20% and 64.53% respectively, indicating that they were easily influenced by the
environment. U8416 was controlled by 4 major genes and 8 minor polygenes. All 4 major genes had positive addi? tive effect on the trait with complementary effect, indicating that additive effect of genes could be enhanced when these genes coexisted. The heritability of the main genes was as high as 87.57%, indicating that the genetic effect of the major genes was significant and the trait was less influenced by the environment. The germination traits that de?
termine the level of seed vigor were regulated by the major gene + polygenes, and the genes of each germination trait showed an interactive effect. In order to provide more recombination opportunities among the interacting genes, the selection intensity in the early generation should not be high.

Key words: Brassica napus L., doubled haploid population, seed vigor, major gene + polygene, genetic effect