Mapping QTLs in tetraploid potato
We have developed, in collaboration with Biomathematics and Statistics Scotland, the theory and user-friendly software for linkage map construction and QTL mapping in autotetraploid species such as the European potato (Luo et al., 2001; Hackett et al., 2001; Hackett et al., 2007).
We have analysed and published the results of the cross between processing clone 12601ab1 and table cultivar Stirling, a cross typical of those made in potato breeding programmes. We have discussed the implications for potato breeding (Bryan et al., 2004; Bradshaw et al., 2004; Bradshaw et al., 2008).
- Quantitative resistance to the white potato cyst nematode derived from Andigena potato CPC2802: QTL of large effect (34% of variation) on linkage group IV of 12601ab1 and QTL of smaller effect (17% of variation) on linkage group XI of 12601ab1.
- Quantitative resistance to late blight derived from wild Mexican species Solanum demissum: QTL of large effect (37% of variation in foliage blight) on linkage group IV of Stirling and QTL on linkage group V of Stirling associated with early maturity and susceptibility to blight (17.5% of variation in foliage blight). Smaller effects at same loci on tuber blight.
- Maturity: QTL of large effect (56% of variation) for early maturity on linkage group V of Stirling.
- Fifteen yield, agronomic and quality traits: 38 QTLs (from 1 to 6 for each trait) identified which individually explained between 5.4 and 15.6% of variation.
- Molecular breeding methods appropriate for QTLs of large effect: aim to introduce them into new cultivars as quickly as possible.
- Efficient multitrait genotypic recurrent selection (see use of progeny tests above) required for large number of genes each of small effect.
References
Bradshaw, J.E., Pande, B., Bryan, G.J., Hackett, C.A., McLean, K., Stewart, H.E. and Waugh, R. 2004. Interval mapping of quantitative trait loci for resistance to late blight [Phytophthora infestans (Mont.) de Bary], height and maturity in a tetraploid population of potato (Solanum tuberosum subsp. tuberosum). Genetics 168, 983 - 995.
Bradshaw, J.E., Hackett, C.A., Pande, B., Waugh, R. and Bryan, G.J. 2008. QTL mapping of yield, agronomic and quality traits in tetraploid potato (Solanum tuberosum subsp. tuberosum). Theoretical and Applied Genetics 116, 193 - 211.
Bryan, G.J, McLean, K., Pande, B., Purvis, A., Hackett, C.A., Bradshaw, J.E. and Waugh, R. 2004. Genetical dissection of H3-mediated polygenic PCN resistance in a heterozygous autotetraploid potato population. Molecular Breeding 14, 105 - 116.
Hackett, C.A., Bradshaw, J.E. and McNicol, J.W. 2001. Interval mapping of QTLs in autotetraploid species. Genetics 159, 1819 - 1832.
Hackett, C.A., Milne, I., Bradshaw, J.E. and Luo, Z. 2007. TetraploidMap for Windows: linkage map construction and QTL mapping in autotetraploid species. Journal of Heredity 98, 727 - 729.
Luo, Z.W., Hackett, C.A., Bradshaw, J.E., McNicol, J.W. and Milbourne, D.M. 2001. Construction of a genetic linkage map in tetraploid species using microsatellite markers. Genetics 157, 1369 - 1385.
