Global genetic diversity in oilseed Brassica rapa

Abstract

Three major simple sequence repeat (SSR) groups were identified in a global collection of 164 oilseed Brassica rapa based on allelic diversity at loci: SSR group 1 (south Asia, predominantly from India, Pakistan, and Nepal); SSR group 2 (predominantly southern and eastern Europe with mostly winter and semi-winter types); and SSR group 3 (northern Europe, mostly from Germany, and many of unknown origin). Nine outliers from several regions were placed in a fourth SSR group, which had the highest allelic diversity per accession of all SSR groups. Analysis of molecular variance of SSR data supported four groups but indicated that genetic variance within populations was high (84%) compared with variance between populations. Flowering habit was classified as winter, spring or semi-winter type, and pollination control as self-incompatible or self-compatible. These phenotypes were distributed across each of the three SSR groups and outliers, although most SSR group 1 accessions were self-compatible spring types, and winter types were mainly from SSR groups 2 and 3. Two SSR sub-groups were present among Indian accessions, both of which contained brown-seeded types, but only one sub-group contained yellow-seeded types (most likely yellow sarson). Eleven B. rapa accessions were misclassified in genebanks as oilseed types but were re-classified as leafy or root vegetable types, and 12 accessions were misclassified as B. rapa and were shown to be allotetraploid or other Brassica species.

Genotypic Variation for Tolerance to Transient Drought During the Reproductive Phase of Brassica rapa

“…Previous experiments in our group reported the self‐incompatibility and genetic diversity of a global collection of 340 accessions of B. rapa , including oilseed, turnip, leafy vegetable and wild types, and we reported a range of self‐incompatibility (Annisa et al , Guo et al. ).…”

“…Nine B. rapa accessions were chosen for this study (Table ) to represent the wide genetic variation in the species based on previous genetic diversity results (Annisa et al , Guo et al. ).…”

“… More detailed information on source and passport data of the 10 accessions is available in Annisa et al () and Guo et al. (). …”

A multiplex PCR for rapid identification of Brassica species in the triangle of U

“…Further improvements to the MPCR in future iterations could see the use of two A genome markers derived from separate A chromosomes. Although not seen in our study, ambiguous samples in which the internal controls fail to operate may be further resolved using other existing methods, such as chromosome counting and ploidy analysis [11, 14]. In contrast, the B genome marker is expected to amplify across diverse species because it is present on all eight of the Brassica B genome chromosomes and has been verified to be B genome specific [20, 21].…”

“…These samples were genotyped previously using SSR markers [11–13] or the B. napus 60K SNP array [14]. In addition, 16 samples of known species identity were included as controls (Table 1).…”