| Over one billion people, more than 1/9th of the global population, are undernourished. Feeding the ever increasing population has to be the most important goal of plant sciences. Since cultivated areas are not likely to increase, I will need to produce more with what is available. This can be summarized in one word: yield. Unfortunately, wheat's yield is expected to increase only 1.13% by 2019, a prediction that if converted into reality will likely indicate that I failed to cope with the world demographic increase. A new strategy to revolutionize wheat production is required, and some believe that this change might be represented by wheat hybrids. Achieving adequate commercial production of wheat hybrids has the potential to nearly double the yield of one of the world's most important staple food. The first fundamental step toward this goal is to develop feasible methodologies to sterilize the male part of the complete wheat flowers. Two fertility-related genes are the primary target of this study, namely the species cytoplasm specific on chromosome 1D, and the desynaptic locus on chromosome 3B. This dissertation summarizes the important achievements obtained toward the cloning of the two loci by means of radiation hybrid functional analysis. Radiation hybrid is a technique that employs radiation to create genetic diversity along the targeted chromosome. Chapter 1 explains in details how this methodology can be applied to plants. The use of radiation hybrid mapping permitted creating a comprehensive map of wheat chromosome 3B, as discussed in Chapter 2, and then expanded the mapping information to identify the 2 Mb location of the desynaptic locus desw2, as discussed in Chapter 3. A similar approach on chromosome 1D allowed first to pinpoint the location of the species cytoplasm specific gene to a region of 2 Mb, as discussed in Chapter 4, and then ultimately to find a strong candidate for this locus, as discussed in Chapter 5. Now that the molecular locations of these genes have been unraveled by this study, their sequence can be streamlined into transformation to ultimately produce female wheat plants, and consequently hybrids. |
