Genetic basis of nitrogen use efficiency at seedling stage analyzed using a recombinant inbred line population derived from an elite rice hybrid

摘要

Improving crop nitrogen use efficiency (NUE) is very important for minimizing environmental problems caused by excess nitrogen application and would be cost-effective for farmers. In this study, we analyzed the genetic components underlying NUE at seedling stage in rice, including main effects, epistatic effects of the QTLs, and QTL by environment interactions (QEs), using a population of 239 recombinant inbred lines (RILs) from a cross between Zhenshan 97 and Minghui 63, the parents of an elite hybrid. A genetic linkage map with 253 DNA maker loci was constructed. The seedlings of RILs were cultivated in low N and normal N solutions. The root, shoot and plant weight in the two N treatments was measured and the relative weight of the two treatmentswas used as the NUE index for each trait. Four to 8 QTLs with main effects were detected for each of the nine traits. Very few QTLs were detected in both low N and normal conditions, and most QTLs for NUE indexes were different from those for traits under the two N treatments, indicating very little commonality in the genetic basis of the traits and their relative performance under low N and normal N conditions. A total of 103 digenic interactions were detected for the 9 traits, and the epistatic effects collectively accounted for large proportions of the variation for several traits. Whereas the effects of QEs appeared to be trivial. The results indicated that NUE in rice seedling featured a complex genetic basis that requires extensive studies for full characterization.