Performance of bmr 6 and 12 Sorghum Mutants in Different Wild Backgrounds Under Salinity

Abstract

Sorghum is one of the bioenergy crops, with considerable tolerance to salinity. The current work was undertaken to assess the salinity tolerance of brown midrib (bmr) mutant lines and wild parents for biomass composition and potential theoretical ethanol yield (TEY). The variation for salinity levels in field plots was significant; hence, salinity screening under controlled environment was performed. The mutant line N 600 (bmr-12) had performed better under field screening (at 10 dS m⁻¹) with fresh stalk yield of 17.3 t ha⁻¹, dry stalk yield of 7.4 t ha⁻¹, and grain yield of 2.0 t ha⁻¹. The performance of bmr-6 and bmr-12 mutant alleles showed that bmr-12 allele, i.e., N 597 and N 600 had performed better than its wild types EHS and Atlas, respectively, for relative fresh and dry biomass index at 20, 40 and 80 days after imposing 150 mM salinity stress. The lines N 597 (13.05 cm² g⁻¹), N 596 (6.84 cm² g⁻¹) and N 593 (7.39 cm² g⁻¹) recorded the highest specific leaf area at 20, 40 and 80 days of stress, respectively. High membrane stability index was recorded in mutants N 596 (bmr-6-85.33%) and N 597 (bmr-12-84.78%) with EHS though under different genetic background under stress. Higher TEY was recorded in N 597 (2219.82 L ha⁻¹), N 600 (2159.79 L ha⁻¹), N 595 (2019.03 L ha⁻¹) and N 598 (1945.33 L ha⁻¹) under stressed conditions, with a moderate reduction of 47.85 and 47.50% in 2014 and 2015, respectively, in TEY.