Nitrogen use efficiency is associated with chlorophyll content in Brazilian spring wheat

Abstract

The use of wheat cultivars with high nitrogen use efficiency (NUE) is essential to reduce production costs and minimize environmental contamination through nitrogen losses. Despite several investigations reported worldwide, NUE still has not been studied in Brazilian wheat varieties. The objective of this study was to evaluate the general and specific combining ability (GCA and SCA) of agronomic traits associated with NUE components in a diallel cross. Six wheat parents and fifteen F2 populations were planted in the field in a randomized block design with three replications. The relative chlorophyll content was measured in flag leaves at the post-anthesis stage, while agronomic traits and NUE components were evaluated at physiological maturity. Additive and non-additive genetic effects were identified controlling NUE components. The parents, Mirante, Valente, and BRS Tangar , showed high values of GCA for NUE components. The chlorophyll B index was significantly correlated with grain yield (0.49*), thousand kernel weight (0.44*), and NUEg (0.50*), indicating that chlorophyll B index can be used as an effective selection criterion in early segregating generations. To our knowledge, this is the first report of genetic variability of nitrogen use efficiency in Brazilian spring wheat.