Genetic mechanisms underlying grain yield

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One hundred years have elapsed since the term 'heterosis' was coined to describe the phenomenon of the superiority of the F1 over the parental genotypes. After more than 60 years of inbred/hybrid breeding resulting in a 7-fold increase in hybrid grain yield, a 2- to 3-fold difference in grain yield between hybrids and inbreds still exists and the magnitude of heterosis remains unchanged. Heterosis fundamentally changes many aspects of the biology of the maize plant, including at the transcriptional level as expression array results have demonstrated differential expression of genes due to both cis- and trans- effects in hybrids as compared to their inbred parents. In this proposal my research group will be exploiting the phenomena of heterosis to identify a set of candidate genes and processes (i.e., regulatory networks) involved in determining potential kernel number in maize. Kernel number is maize is directly proportional to grain yield and this developmental process is referred to as 'sink establishment'. In addition we will be examining several paradigms that involve or influence sink establish: yield stability, G×E, leaf number, and flowering time.