three crops test for the ODO breeding method

Hybrid vigor is the leading concept that rules crops breeding for almost a century. Yet, the exact mechanism that underlies heterosis is not clear. Over dominance interaction between alleles is one of the possible explanations. Our preliminary results indicated that severe developmental mutations at the heterozygous state have significant potential to improve plant performance. This led us to propose the ‘ODO breeding method’ that is based replacing a parental line of a successful hybrid with its mutated from to improve hybrid performance. Our BARD research challenged this method in three crop systems: maize, tomato and melon. In maize we could not detect any effect of mutant heterozigosity on yield or yield components when hybrids were tested however when we analyzed the effect of heterozigosity in mutant genes at B73 genetic background we could detect ODO in yield components using certain mutants. Our results indicate that the potential of utilizing the ODO Breeding Method for maize remains unclear. In tomato we overcame technical problems we faced in creating an EMS mutation library in indeterminate glasshouse tomatoes and now we have in our hands advanced material to study the putative ODO hybrids. We transferred some of the promising ODO mutations from M82 to indeterminate glasshouse tomatoes and putative ODO hybrids are ready to be evaluated this winter. In addition, we tested the effect of In melon we compared putative ‘ODO hybrids’ with their isogenic hybrids lacking the mutant allele and our results indicated a potential for the ODO breeding method to improve yield, fruit number per plant, and carotenoids content. Additional experiments are required to estimate better the expected success percentage of the ODO breeding method in melon so that it will become a recommended practice for improving hybrid performance. Based on our results we can't yet recommend the 'ODO breeding method' as a general tool to improve hybrid performance and more efforts are necessary to evaluate the percent of success of this method. The increased carotenoid content we found in association with CRTISO heterozygosity is promising and additional experiments are currently being performed to characterize this finding.