Wednesday, November 15, 2006

Genetic Analysis of Preharvest Sprouting in a 2-Row Barley Cross.

Steven E. Ullrich, J. A. Clancy, H. Lee, and I. A. del Blanco. Washington State Univ, Dept.Crop.&Soil Sci, PO Box 646420, Pullman, WA 99164-6420

Preharvest sprouting (PHS) can be a problem in barley production, especially of malting barley. Rain or very high humidity from near physiological maturity (PM) onward can cause sprouting in spikes. This has very serious consequences for malting of grain, since rapid and complete germination is critical. Much information has been gained by studying the genetic control of dormancy (measured as percent germination) in barley. The objective of this study was to determine if the U.S. Bartley Genome Project doubled haploid mapping population developed and QTLs discovered in previous research of dormancy in the 2-row barley cross ‘Harrington’/TR306 (H/TR) can be applied or related to the genetic control of PHS. PHS was measured as ‘sprout score’ (SSc) based on visual sprouting in mist chamber-treated spikes at 0 and 14 d after PM and as ‘alpha-amylase activity’ (AA) in kernels taken from mist chamber-treated spikes that showed little or no visible sprouting at 0 and 14 d after PM. Germination percentage was also measured at 0 and 14 days after PM. QTLs for dormancy were previously mapped to chromosomes 5L (1HL) and near the 7L (5HL) telomere. Interval mapping of the H/TR population grown in two environments (greenhouse and field) for SSc revealed QTLs on chromosomes 1 (7H), 2 (2H), 3 (3H), and 7 (5H) and for AA on chromosomes 1, 3 and 7. The two dormancy QTLs previously identified on chromosomes 5 and 7 were confirmed in this study, and QTLs on chromosomes 1 and 2 were newly identified. Some of the PHS QTLs coincide with known dormancy QTLs, but some do not. Some of the PHS and dormancy QTLs identified here coincide with PHS and dormancy QTLs identified from other crosses. QTLs identified should aid breeding efforts for balance between preharvest sprouting and dormancy in barley and other cereals.

Handout (.pdf format, 218.0 kb)