[Gene expression analysis of near-isogenic lines for different heterosis in maize]

In this report, we used three pairs of near-isogenic lines( NILs) 478,488-1 and 488-2, which are different in seed size and leaves above the top ear, to make a survey of the expressions of six genes in leaf tissues of these NILs series in order to find whether these genes serve as models for the rate-limiting genes in the heterosis. Our results showed that some of genes may play a role in heterosis response either through increased or decreased expression. When all six genes were considered as a whole, they showed a tendency for higher gene expression in 488-1 than in 488-2 and in 478, and in 488-1 x 340 than in 478 x 340 and in 488-2 x 340. Sus1, Sh1 and ZmSps34-3' were good candidate genes because they have been proposed to be rate-limiting for the seed size and grain weight of the individuals heterosis. And also, in order to seek a molecular genetic dissection of heterosis, two main theories, dominance and overdominance, which hold the classical explanation for the heterosis, were discussed too.