Agronomic and physiological characterization of Sorghum germplasm under limited and non-limited nitrogen conditions

Nitrogen deficiency is a significant environmental stress affecting global agricultural production. Exploring nitrogen-efficient crops like sorghum mitigates yield losses and ensures food security. A two-year study was conducted at the Eastern Mediterranean Agricultural Research Institute, Adana, Turkey, involving 125 sorghum accessions and 6 commercial hybrids under limited (N-) and non-limited nitrogen (N+) conditions. The results revealed significant variation in morpho-physiological and yield traits, including plant height, grains per panicle, SPAD, stomatal conductance, and grain yield. While phenological traits were delayed under non-limited nitrogen conditions, traits like thousand-grain weight and fluorescence parameters remained consistent. Positive correlations were observed among several traits under both nitrogen conditions, including grain yield, NUE, and WUE. In the non-limited nitrogen experiment, the constellation plot divided the germplasm into two main groups (A and B) and further subdivided. Group A had fewer accessions than Group B. The germplasm was similarly divided in the limited nitrogen experiment, with Group B having more accessions. Twenty-three accessions showed superior performance based on grain yield under limited nitrogen conditions, making them ideal candidates for breeding nitrogen-efficient varieties. This study underscores the variability and adaptability of sorghum accessions under different nitrogen conditions, offering valuable insights for future breeding programs.