No abstract

Cultivation of spinach requires high amounts of nitrogen (N), which puts a strain on the environment. A sustainable solution to this problem is to breed for crops with higher N use efficiency (NUE). The aim of this study was to provide tools for molecular breeding and to elucidate the genetic variation of factors contributing to NUE in spinach. A cross was made between two F 1 hybrid cultivars contrasting in NUE. Several F1 progeny were selfpollinated and based on evaluation of the F2 generation, a mapping F 2 population (335 individuals) of a single F1 was selected. SNP markers for the genetic map were discovered by RNA sequencing of the two parent cultivars, and 283 SNP markers were used to produce a genetic map comprising of six linkage groups (P01-P06), ranging in size from 46 to 116 cM. NUE related traits were determined for a set of F 2:3 families grown under low and high N conditions in a hydroponics system under an Ingestad N-addition model. Interval mapping analysis detected 39 traitspecific QTLs, with several QTLs accumulating on P01 and P02 of the linkage map. The QTLs and in particular the P01 and P02 regions provide potential targets for the improvement of NUE in spinach.