QTL and QTL?�?Environment Effects on Agronomic and Nitrogen Acquisition Traits in Rice

Agricultural environments deteriorate due to excess nitrogen application. Breeding for low nitrogen responsive genotypescan reduce soil nitrogen input. Rice genotypes respond variably to soil available nitrogen. The present study attemptedquantification of genotype � nitrogen level interaction and mapping of quantitative trait loci (QTLs) associated withnitrogen use efficiency (NUE) and other associated agronomic traits. Twelve parameters were observed across a set of82 double haploid (DH) lines derived from IR64/Azucena. Three nitrogen regimes namely, native (0 kg/ha; no nitrogenapplied), optimum (100 kg/ha) and high (200 kg/ha) replicated thrice were the environments. The parents and DHlines were significantly varying for all traits under different nitrogen regimes. All traits except plant height recordedsignificant genotype�environment interaction. Individual plant yield was positively correlated with nitrogen use efficiencyand nitrogen uptake. Sixteen QTLs were detected by composite interval mapping. Eleven QTLs showed significantQTL�environment interactions. On chromosome 3, seven QTLs were detected associated with nitrogen use, plant yieldand associated traits. A QTL region between markers RZ678, RZ574 and RZ284 was associated with nitrogen use and yield.This chromosomal region was enriched with expressed gene sequences of known key nitrogen assimilation genes

Senapathy Senthilvel, Kunnummal Kurungara Vinod, Palaniappan Malarvizhi, Marappa Maheswaran, 'QTL and QTL?�?Environment Effects on Agronomic and Nitrogen Acquisition Traits in Rice', Journal of Integrative Plant Biology, vol. 50(9), pp.1108-1117, Wiley, 2011