Combining Genes for Pre-Harvest Sprout Resistance in White Wheat Kirsten Thomas and Herb Ohm
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Transcript of Combining Genes for Pre-Harvest Sprout Resistance in White Wheat Kirsten Thomas and Herb Ohm
Combining Genes for Pre-Harvest Sprout Resistance
in White WheatKirsten Thomas and Herb Ohm
#125
IntroductionPre-harvest sprouting (PHS) is a significant problem in white wheat in humid climates globally that leads to severely lowered grain quality and economic loss for producers. Pre-harvest sprouting occurs when the seed germinates before it is harvested. The most effective method for controlling pre-harvest sprouting is through the use of PHS resistant cultivars (cvs.). Resistance genes for the white wheat cultivars Leader, Cayuga, and RioBlanco have been identified and mapped. The objective of this research is to combine the PHS resistance of these three cultivars and determine if PHS resistance is augmented with the combination of the resistance factors. MethodsThe white wheat cvs. Leader, Cayuga, and RioBlanco have PHS resistance that have been mapped to different chromosomes. The PHS susceptible white wheat line Van98W-170WS is included here as a negative control. The single crosses Leader x Cayuga (cross ‘A’) and RioBlanco x Cayuga (cross ‘B’) were made, and then F1 plants from the two single crosses were crossed (cross ‘C’) to combine the respective PHS resistance factors of the three PHS resistance donor cultivars. The three PHS resistance donor parent cultivars and F1 plants from cross C were screened with the respective markers from published sources (Table 1).
Table 1. Published Markers Associated with PHS Resistance
Cultivar Markers Chromosome
Leader barc170 4AL
gwm397
gwm637
hbe03RioBlanco barc12 3AS
barc54barc321
Cayuga barc55 2Bwmc453
Table 2. Crosses Made to Combine PHS Resistance Factors
F1 Cross (single) ParentageCross A Leader/CayugaCross B RioBlanco/Cayuga
F2 Cross (double) Parentage
Cross C Leader/Cayuga// RioBlanco/Cayuga
ResultsTo date, the presence of the published markers (Table 1) in the parent cultivars has been confirmed. The following shows the gel images (Figures 2-3) of the parent cultivars and their respective markers (Table 3):
Figure 2.
Table 3. Location of Parent Cultivars with Respective Markers on the Gels
Information for Figure 2: Gel 1 Information for Figure 3: Gel 2
Cultivar Marker Gel Lane Cultivar Marker Gel LaneControl barc55 2 Control barc54 2Cayuga barc55 3 RioBlanco barc54 3
Cayuga barc55 4 RioBlanco barc54 4
Cayuga barc55 5 RioBlanco barc54 5
Control wmc453 6 RioBlanco barc54 6
Cayuga wmc453 7 RioBlanco barc54 7
Cayuga wmc453 8 RioBlanco barc54 8
Cayuga wmc453 9 Control barc57 9
Control gwm397 10 RioBlanco barc57 10
Leader gwm397 11 RioBlanco barc57 11
Leader gwm397 12 RioBlanco barc57 12
Control barc170 13 RioBlanco barc57 13
Leader barc170 14 RioBlanco barc57 14
Control hbe03 15 RioBlanco barc57 15
Leader hbe03 16 Control barc321 16
Leader hbe03 17 RioBlanco barc321 17
Control gwm637 18 RioBlanco barc321 18
Leader gwm637 19 RioBlanco barc321 19
Leader gwm637 20 RioBlanco barc321 20
Control barc12 21 RioBlanco barc321 21
RioBlanco barc12 22 RioBlanco barc321 22
RioBlanco barc12 23 Control wmc453 23
RioBlanco barc12 24 Cayuga wmc453 24
RioBlanco barc12 25 Cayuga wmc453 25
RioBlanco barc12 26 Cayuga wmc453 26
Figure 3.
ConclusionThe expected outcome of this research is the identification of a true-breeding white wheat line that has all of the PHS resistance QTLs from all three parents. It is hypothesized that the PHS resistance of lines with multiple resistance QTLs will have more effective PHS resistance (augmented resistance) than the parent cultivars.
Research Plans:Current•Grow parent cvs. and selected F2 plants from cross ‘C’ in a greenhouse, August-November 2011
•Screen F2 plants with markers to identify plants that have the PHS resistance factors of all three parents in homozygous state.
Figure 1. A continuum of pre-harvest sprouting in wheat. The most resistant plants are
shown at right, while the most susceptible are shown at left.
Photo courtesy of the University of Minnesota.
References1. Li, C., P. Ni, M. Francki, A. Hunter, Y. Zhang, D. Schibeci, H. Li, A. Tarr, J. Wang, M. Cakir, J. Yu, M. Bellgard, R. Lance, R. Appels. 2004. Genes controlling seed dormancy and pre-harvest sprouting in a rice-wheat-barley comparison. 4:84-93.2. Lui, S., S. Cai, R. Graybosch, C. Chen, and G. Bai. 2008. Quantitative trait loci resistance to pre-harvest sprouting in US hard white winter wheat Rio Blanco. Theoretical and Applied Genetics. 117:691-699.3. Munkvold, J.D., J. Tanaka, D. Benscher, and M.E. Sorrels. 2009. Mapping quantitative trait loci for preharvest sprouting resistance in white wheat. Theoretical and Applied Genetics. 119:1223-1235.4. Torada, A., S. Ikeguchi, and M. Koike. 2005. Mapping and validation of PCR-based markers associated with a major QTL for seed dormancy in wheat. Euphytica. 143:251-255.
Future•Dec2011-Jan2012: vernalize F3 progeny families from selected F2 plants; also vernalize 15 seedlings of Leader, Rio Blanco and Cayuga; and white and red wheat checks, including the PHS susceptible white wheat lines, Van98W-170WS (early maturity) and an additional line to be decided (midseason maturity), and the winter red wheat cvs. Clark (early maturity) and INW1131 (midseason maturity).•Late Feb2012: transplant F3 families and cvs./lines to a field nursery; screen several F3 plants of each family with markers to verify presence/homozygosity of the PHS resistance factors of all three parents; record data on preharvest sprouting severity of the grain samples.•Aug2012 – Nov2012: Determine PHS of F4 lines, donor parents, and white and red checks under controlled misting system in a greenhouse.