The Relationship Between Alteration Of Gene Expression And Heterosis In Maize

Using DDRT technique to examine 12 maize inbred lines and 33 hybrids combined (in imcomplete diallel cross disign) from them, we study the relationship between differential gene expression patterns of spikelets of four periods and its relationship with performance of seven main agronomic traits, and with their heterosis index. Investigating the readable bands (1000-200bp), there are much differential genes expressed between hybrids and their parents. Some differences are quantitative and some are qualitative. Quantitative differences are very difficult to study. Qualitative differences have four patterns: 1) bands expressed only in one parent, 2) bands expressed only in both parents, 3) bands expressed only in one parent and F1, 4) bands expressed only in F1. Studying the correlations between each pattern and each performance of the seven agronomic traits, or each pattern and the hybrid index of seven agronomic traits, there are clear correlations only in the first period when the spikelets haven't come out. And evaluation efficiency of over-standard hybrid hetorosis index is alike with that of middle-parents heterosis index.Choosing the three highest and three lowest hybrids, DDRT again, 160 differential expressed bands were gotten, 56 from the highest three and 104 from the lowest three. Using reverse Northern-Blot, 44 positive bands were gotten. Through sequencing, it was found that these genes are from so many different metabolism routes, showing that there are special differential genes expressed in each of the so many metabolism routes. And differential expressed genes from different period are different, showing that there are special differential genes expressed in different period.