Transfer and mapping of the shoot-differentiation locus Shd1 in barley chromosome 2

Abstract

The locus Shd1, which we previously mapped to the long arm of chromosome 2 of Hordeum vulgare L., controls the differentiation of shoots from immature barley embryo callus. The locus has major effects and its action explains more than 65% of the total genetic variance in the shoot-differentiation rate. The allele of cultivar Kanto Nakate Gold designated Shd1K has a significant positive effect on the shoot-differentiation rate, whereas Shd1A of cultivar Azumamugi does not promote shoot differentiation. To identify gene products and characterize the function of Shd1, a set of near-isogenic lines is essential. In this study we produced BC5F1 plants by repeated backcrossing of 'Azumamugi' to F1 plants ('Azumamugi' x 'Kanto Nakate Gold'). The BC5F1 plants were examined for their RFLP genotype and for the shoot-differentiation ability of immature embryo-derived callus. The results indicated that the Shd1 locus was located in a chromosomal region between MWG2081 and MWG503 that flanks the MWG801, cMWG699, v (ear type), and MWG865 loci. Shd1K from 'Kanto Nakate Gold' functions effectively in the genetic background of 'Azumamugi', an indication that backcross breeding is possible for production of near-isogenic lines that would be very suitable for tissue culture.

Identification of QTLs controlling tissue-culture traits in barley (Hordeum vulgare L.)

“…This QTL accounted for 10.0% of the phenotypic, and 12.0% of the genotypic, variance ( Table 2). The position of the QTL was in close agreement with that of Shd1, previously reported by Komatsuda et al (1995). In the region of Shd1, the QTL for CG was also identified ( Mapping QTLs for GS By CIM analysis in the F 10 generation, two well-dissociated QTLs for GS were identified on chromosome 7H (Fig.…”

“…Shd1 on chromosome 2H has been consistently identified in the BC 1 F 1 and BC 5 F 1 generations (Komatsuda et al 1993(Komatsuda et al , 1995, and in the F 10 generation (this study). In the F 7 generation, however, Shd1 was not detected (Fig.…”

“…In a BC 1 F 1 population of this cross, linkage relationships were observed between a QTL for shoot differentiation ability (Shd1) and the vrs1 locus (row-type) on chromosome 2H, and also between another QTL for shoot differentiation ability and the uzu locus (semi-brachytic) on chromosome 3H (Komatsuda et al 1993). By further analysis of BC 5 F 1 plants, the detailed position of Shd1 was determined in the MWG2081-MWG503 interval (Komatsuda et al 1995). However, the map position of the QTL associated with the uzu locus has not been determined, and the whole barley genome has not yet been analyzed for other QTLs.…”

Development of Gene Based STS Markers in Wheat

“…Easy to use STS markers will allow different linkage maps to be integrated effortlessly. For example, QTLs for shoot differentiation in barley have been mapped on the long arm of chromosome 2H in three different mapping populations: Azumamugi × Kanto Nakate Gold (Komatsuda et al, 1993;1995), Steptoe × Morex (Mano et al, 1996), and Harrington × TR306 (Takahashi et al, 1997). A short term disadvantage for the STS PCR primers as compared to RAPDs primers is the need for sequence analysis before primers can be designed.…”

Mapping QTLs for Tissue Culture Response in Soybean (Glycine max (L.) Merr.)

“…Furthermore, the construction of genetic maps has provided a tool for identification of the number, significance and location of QTLs (Bolibok et al, 2007;. Recent reports have identified the QTLs for tissue culture response in many plant species, such as in rice (He et al, 1998;Kwon et al, 2002;Taguchi-Shiobara et al, 1997;, maize (Armstrong et al, 1992;Krakowsky et al, 2006;Murigneux et al, 1994), barley (Komatsuda et al, 1995;Mano et al, 2002), wheat (Jia et al, 2007;Torp et al, 2001), rye (Bolibok et al, 2007), sunflower , tomato (Koornef et al, 1993) and alfalfa (Yu and Pauls, 1993).…”