Genetic variation in phytosterol content of winter rapeseed (Brassica napus L.) and development of NIRS calibration equations

Rapeseed oil is one of the richest natural sources of phytosterols, known to reduce the LDL-cholesterol levels, one of the major cardiovascular disease risk factors. Increasing the phytosterol content in rapeseed could give an added value to the oil and derived products. Our objective was to analyse the genetic variation of phytosterol content in modern winter rapeseed cultivars and resynthesized lines following field experiments and to develop a near-infrared reflectance spectroscopic (NIRS) calibration for high throughput estimation of phytosterol content. Phytosterol content as analysed by gas–liquid chromatography ranged from 3565 to 4800 mg/kg seed for modern cultivars and from 2079 to 4329 mg/kg seed for resynthesized lines. The NIRS calibration showed a high fraction of explained variance in cross-validation of 0.81 for total phytosterol content and the standard error of cross-validation was 241 mg/kg. The results show that the cultivars contain already high phytosterol contents. The NIRS calibrations developed for total phytosterol content should be useful for germplasm screening and in breeding programmes aimed at increasing the phytosterol content in rapeseed.