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Combining Genes for Pre-Harvest Sprout Resistance in White Wheat Kirsten Thomas and Herb Ohm

Combining Genes for Pre-Harvest Sprout Resistance in White Wheat Kirsten Thomas and Herb Ohm. #125. Introduction

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Combining Genes for Pre-Harvest Sprout Resistance in White Wheat Kirsten Thomas and Herb Ohm

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  1. Combining Genes for Pre-Harvest Sprout Resistance in White Wheat Kirsten Thomas and Herb Ohm #125 Introduction Pre-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 RioBlancohave 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. Results To 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. Figure 3. Methods The white wheat cvs. Leader, Cayuga, and RioBlancohave 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 RioBlancox 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). • 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. • 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. Conclusion The 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. References 1. 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. 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.

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