GrainGenes
A Database for Triticeae and Avena
characters with the Wsp3 and amo1 loci.
J.S. Swanston and B.P. Forster, Scottish Crop
Research Institute, Mylnefield, Invergowrie,
Dundee DD2 5DA, U.K.
Doubled haploid (DH) inbred lines were produced from the cross Blenheim x BE285 (Swanston, 1992). BE285 carries the amo1 gene and also differs from cv. Blenheim at the Wsp3 locus, so it was decided to investigate whether factors associated with Wsp3 contributed significantly to variation, within normal and high amylose populations, for quality characters. The results reported, here, are from an initial experiment using a limited number of DH inbred lines.
The 2 isoforms WSPa and WSPb, alternative alleles at the Wsp3 locus, were detected in iso-electric focussing gels (Forster et al., 1991). Division into normal (AMO1) or high (amo1) amylose populations was achieved as described by Swanston (1992). Samples were measured for thousand grain weight (TCW), grain nitrogen content (N), by the Dumas combustion method (Buckee, 1994) and grain milling energy (GME) by a Comparamill (Allison et al., 1979). The ratio of B to C hordein was determined by high performance liquid chromatography (HPLC) (Griffiths, 1986). This method also gives a semi-quantitative measurement of total hordein content (HOR). B-amylase activity (BAM) was determined by an automated method (Scharoun and Saletan, 1965) following extraction in 1% papain as described by Allison and Swanston (1974). Water uptake during steeping (H2O) was measured as grain moisture content following a 48 hr steep, incorporating an air rest phase (Swanston and Taylor, 1990).
There were significant differences at both loci for N and BAM, with the Blenheim alleles raising BAM in both cases. The Blenheim allele at the Wsp3 locus also increased N, but to a lesser degree than amo1. The 2 loci may have an additive effect in increasing N and this will be investigated further. No differences at the Wsp3 locus were detected, here, for HOR or GME, but future testing with larger populations is intended. Increases in both HOR and GME were observed in association with amo1.
No differences in B to C hordein ratio were observed between normal and high amylose populations, but the Blenheim allele at the Wsp3 locus was associated with a higher ratio. This differs from the suggestion of Griffiths (1986) that increases in grain nitrogen led to a reduction in the proportion of B hordein. There was also an increase in TCW, associated with the Wsp3b allele, in the high amylose population, but this was not significant among normal amylose lines. The Wsp3b allele was also associated with increased H20, but the effect was less than that associated with amo1.
Thomas et al. (1991) suggested that associations of quality characters with the Wsp3 locus were due to linkage. It is also possible that the amo1 gene is acting as a marker for closely linked, deleterious characters from its parent, Glacier (Swanston, 1994). The results presented here are preliminary and derive from very small populations, but appear to indicate that the segments of chromosome, surrounding the amo1 and Wsp3 loci, may be of considerable importance to quality in barley.
Table 1 Results of grain tests for inbred lines differing at 2 loci.
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Alleles AOM1¹ AMO1¹ amo1² amo1²
wsp-3(a)² wsp-3(b)¹ wsp-3(a)² wsp-3(b)¹
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N (%) 1.36^a^ 1.41^b^ 1.46^c^ 1.56^d^
BAM (E.U.)* 43.0^c^ 47.9^d^ 27.9^a^ 33.9^b^
GME (Joules) 609.5^a^ 610.9^a^ 805.8^b^ 795.6^b^
HOR (A.U.)# 611.4^a^ 604.5^a^ 680.7^b^ 715.3^b^
B:C ratio 2.39^a^ 2.60^b^ 2.43^a^ 2.66^b^
TCW (g) 46.99^bc^ 47.24^c^ 43.72^a^ 46.21^b^
H20 (% moist) 38.39^a^ 39.71^b^ 41.28^c^ 41.99^d^
No. of lines 6 6 4 4
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Values followed by a different letter are significantly different at the 1%
level.
* E.U. - Enzyme Units, # A.U. Arbitrary Units
¹ Blenheim Allele, ² BE285 Allele
References
Allison, M.J., I.A. Cowe, R. Borzucki, F.M. Bruce and R. McHale. 1979. Milling energy of barley. J. Inst. Brew., 85:262-264.
Allison, M.J. and J.S. Swanston. 1974. Relationships between B-amylase polymorphisms in developing, mature and germinating grains of barley. J. Inst. Brew. 80: 285-291.
Buckee, G.K. 1994. Determination of total nitrogen in barley, malt and beer by Kjeldahl procedures and the Dumas combustion method - collaborative trial. J. Inst. Brew. 100:57-64.
Forster, B.P., D.M. Thompson, J. Watters and W. Powell. 1991. Water soluble proteins of mature barley endosperm: genetic control, polymorphism and linkage with B-amylase and spring/winter habit. Theoret. App. Genet. 85:120-126.
Griffiths, D.W. 1986. The ratio of B to C hordeins in barley as estimated by high performance liquid chromatography. J. Sci. Food Agric. 38:229-235.
Scharoun, J. and L.T. Saletan. 1965. Automated determination of the diastatic power of malt and sulfur dioxide in beer. Technicon Symposium "Automation in Analytical Chemistry", New York:66-72.
Schondelmaier, J., A. Jacobi, G. Fischbeck and A. Jahoor. 1992. Genetical studies on the mode of inheritance and localization of the amo1 (high amylose) gene in barley. Plant Breeding 109:274-280.
Swanston, J.S. 1992. The milling energy of inbred lines carrying the amo1 (high amylose) gene. BGN 22:66-67.
Swanston, J.S. 1994. Malting performance of barleys with altered starch composition. PhD Thesis, Heriot-Watt University, Edinburgh.
Swanston, J.S. and K. Taylor. 1990. The effects of different steeping regimes on water uptake, germination rate, milling energy and hot water extract. J. Inst. Brew. 96:3-6.
Thomas, W.T.B., W. Powell, J.S. Swanston and B.P. Forster 1991. The associations between the linked loci mlo, B-amy-1 and WSP-3 and quantitative characters in barley. Proc. of EUCARPIA (Cereal Section) Meeting, Schwerin:255-260.