Evaluation of nitrogen use efficiency in the Maksimir 3 Synthetic maize population

Abstract

Nitrogen use efficiency (NUE) has become an important trait for sustainable agriculture. Traits present in maize (Zea mays L) landraces that contribute to adaptation in nitrogen-limited environments are not easily implemented directly into modern maize breeding programs. Thus, the landraces might be improved by recurrent selection and afterwards used as source of certain traits for elite breeding material. The Maksimir 3 Synthetic (M3S) maize popu¬lation was created from landraces traditionally grown under low levels of soil fertility. The synthetic was subjected to recurrent selection for yield during three cycles and for improved NUE in the fourth cycle. In order to determine the effect of four cycles of recurrent selection, performance of populations per se (S0), population testcrosses, and populations per se selfed (S1) were evaluated in field trials under high and low nitrogen input conditions at four lo¬cations during 2010. The S0 populations had significantly higher grain yield (+20.6%), ear diameter (+2.6%), 1000 kernel weight (+3.3%) and ear leaf chlorophyll content (+31.2%) at the high nitrogen fertilization rate as compared to the low nitrogen fertilization rate. The S1 populations and testcross populations responded similarly to nitrogen fertilization. Genotype x nitrogen interaction for yield was not significant, but indication of specific adaptation to the nitrogen deficient environments was found. After the fourth cycle of recurrent selection, a significant increase in grain yield was found at both levels of nitrogen fertilization.