Fig.1 Overview of the experimental design. The rapeseed population used in this study was based on crossings of 5 different founder lines (P1 to P5) with a common elite line (L1). The resulting 251 pollinators were crossed with 2 different male-sterile inbred lines (M1 and M2), resulting in 410 test hybrids (A). Across-generation prediction was performed by using NIRS data obtained from the pollinators, grown at 1 location, to predict phenotypic traits of the hybrids, grown at 5 locations (B). Within-generation predictions were performed by using NIRS data and phenotypic traits both obtained from the hybrids (C to E). Here, phenotypic traits were obtained from all 5 locations, while NIRS data was obtained either from all 5 locations (C and E) or from single locations (D). Cross-validation was performed by randomly dividing the hybrid population into 80% for the training set and 20% for the test set with 200 repetitions (B to D) or by using hybrids, which descend from 4 of the 5 original crosses as the training set and the remaining subfamily as test set (E).