Genetic diversity, relationships among traits and selection of tropical maize inbred lines for low-P tolerance based on root and shoot traits at seedling stage.

The tropical maize breeding for low-P tolerance and good performance under low-P stress environments can be achieved through selection based on root morphology traits at seedling stage. Here, we assessed the genotypic variation and genetic diversity of a panel of 151 tropical maize inbred lines for root and shoot seedling traits, investigated the relationship among traits and selected a set of promising inbred lines for low-P tolerance and performance. We evaluated the inbred lines at seedling stage in a greenhouse experiment under two conditions: applied P (AP) and non-applied P (NAP).

Combining ability for agronomic traits among commercial maize hybrids under low and high nitrogen inputs targeting the development of breeding populations.

Commercial hybrids are the main germplasm source for developing maize lines in breeding programs in Brazil; additionally, nitrogen (N) is one the major limiting maize production in Brazilian tropical areas. Here, we assessed the combining ability among ten commercial hybrids under contrasting N inputs and selected the best parental hybrids to develop breeding populations for optimal and N-stress environments. We evaluated the 45 F1 crosses for agronomic traits under contrasting N inputs and over two summer seasons.