English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Presently, most cruciferous vegetables are F1 hybrid varieties whose seeds are produced using the self-incompatibility (SI) system. In addition, high F1 purity, implying a high proportion of F1 hybrids in total harvested seeds, is required for seeds due to the recent mechanization and intensive production of fresh vegetables. However, it is very difficult to stably produce high purity F1 seeds, because actually there is not complete SI. Therefore, raising parental lines with a stable and high level of SI has been an important breeding objective (Niikura et al. 2004). SI in cruciferous plants is controlled by a series of multiple alleles (S) acting sporophytically (Bateman 1955). More than 30 S-haplotypes have been identified in Brassica rapa (Hinata and Nishio 1978, Nou et al. 1993, Sakamoto and Nishio 2001). Studies on S-haplotypes have been carried out since the first identification of the S-locus-specific glycoprotein (SLG) which occurs in the stigma papillae in B. oleracea (Nasrallah and Wallace 1967), and SLG has been isolated and sequenced (Nasrallah et al. 1985, 1987). Shaplotypes can be assigned to one of two classes (class-I or class-II) by sequence homology of SLG. In B. rapa, out of 27 S-haplotypes, at least 18 S-haplotypes belong to class-I and 5 S-haplotypes belong to class-II (Nishio et al. 1996). By the analysis of S-haplotype, it was confirmed that SRK (S receptor kinase), which is closely linked to SLG is the S stigma determinant, and SP11/SCR (S-locus protein 11 or S-locus cystein-rich protein) is the S pollen determinant in the SI system (Schopfer et al. 1999, Takasaki et al. 2000, Shiba et al. 2001). There are genetic variations in the level of SI (Haruta 1962, Ruffio-Chable et al. 1997, Niikura and Matsuura 1999), and SI can be easily repressed internally by individual senescence or externally by high temperatures (Haruta 1962, Matsubara 1980, Okazaki and Hinata 1987). We assumed that using a more reliable evaluation of the level of SI to select the parental lines would lead to the stable production of F1 seeds with a higher purity. By performing artificial self-pollination of opened flowers (artificial self-pollination test) in the crucifer Raphanus sativus L. (radish), we demonstrated that the level of SI is almost independent of the Slocus (Niikura and Matsuura 1999). Based on our data, even if one parental line which shows a high level of SI is used for F1 seed production, the F1 seed purity sometimes decreases, not only in radish but also in Chinese cabbage and turnip (both B. rapa) (Niikura et al. 2003). In the present study, we evaluated the level of SI in B. rapa by using insectpollination, which occurs in actual F1 seed production fields and whose effectiveness was demonstrated in R. sativus (Horisaki et al. 2003). We examined the usefulness of insect-pollination compared with artificial self-pollination in B. rapa.

Effectiveness of Insect-pollination to Evaluate the Level of Self-incompatibility and Genetic Variation in Brassica rapa L.