QTL and QTL x environment effects on agronomic and nitrogen acquisition traits in rice.
Agricultural environments deteriorate due to excess nitrogen application. Breeding for low nitrogen responsive genotypes can reduce soil nitrogen input. Rice genotypes respond variably to soil available nitrogen. The present study attempted quantification of genotype x nitrogen level interaction and mapping of quantitative trait loci (QTLs) associated with nitrogen use efficiency (NUE) and other associated agronomic traits. Twelve parameters were observed across a set of 82 double haploid (DH) lines derived from IR64/Azucena. Three nitrogen regimes namely, native (0 kg/ha; no nitrogen applied), optimum (100 kg/ha) and high (200 kg/ha) replicated thrice were the environments. The parents and DH lines were significantly varying for all traits under different nitrogen regimes. All traits except plant height recorded significant genotype x environment interaction. Individual plant yield was positively correlated with nitrogen use efficiency and nitrogen uptake. Sixteen QTLs were detected by composite interval mapping. Eleven QTLs showed significant QTL x environment interactions. On chromosome 3, seven QTLs were detected associated with nitrogen use, plant yield and 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.
Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore 641003, India.
Senapathy
S
Senthilvel
Kunnummal Kurungara
KK
Vinod
Palaniappan
P
Malarvizhi
Marappa
M
Maheswaran
D000383:Agriculture; D003433:Crosses, Genetic; D004777:Environment; D008040:Genetic Linkage; D005838:Genotype; D006238:Haploidy; D009584:Nitrogen / Q000378:metabolism*; D012275:Oryza / Q000235:genetics*; D010641:Phenotype; D020161:Physical Chromosome Mapping; D025341:Principal Component Analysis; D040641:Quantitative Trait Loci / Q000235:genetics*; D019655:Quantitative Trait, Heritable
D009584:Nitrogen