Correlation of agronomic traits and micronutrient elements of colored wheat

Colored wheat has become a research hotspot in biofortified breeding as a result of its richness in various microelements. Previous studies have mainly focused on the comparative analysis of agronomic traits and the microelements Se, Zn, and Cr in a few varieties of colored wheat; however, reports on the phenotypic correlation between agronomic traits and microelements in colored wheat remain scarce. To address this, a comparison of field varieties was set up from October 2021 to June 2022 in the Luancheng Agricultural Ecosystem Experimental Station of Chinese Academy of Sciences. A total of 19 colored wheat germplasm resources and one control white wheat variety from the Huanghuai wheat area were tested. Detection, t-test, and related and gradual regression analyses were used to determine the correlation between agronomic traits and 16 microelements of colored wheat. The results showed that the spike length, number of spikes per plant, harvest index, and yield per unit area of the 19 colored wheat germplasm resources varied significantly from that of the control white wheat, among which yield per unit area of ‘Zirui 8’ and ‘Jizimai 2’ increased by 7.31% and 6.72% compared to that of the white wheat ‘Shimai 22’, respectively. The yield per unit area was significant positively correlated with 1000-grain weight (P<0.01), and significant negatively correlated with contents of Cu (P<0.01), Zn (P<0.01), and Ag (P<0.05). The first related path was Sr → number of spike per plant → Ag → yield per unit area, the second related path was Ni → Co → Fe → V → spike length, and the third related path was Mn → Sn → Mo → grain number per spike → 1000-grain weight → Cu → Zn → yield per unit area. Five traits, namely V, Cu, and Sr contents and plant height and grain number per spike, jointly determined 83.4% of the variation of yield per unit area. These results provide a theoretical basis for the biofortified breeding of colored wheat.