Assessment of sorghum near isogenic lines (NILs) for moisture stress tolerance by drought stress indices

Abstract

Drought, in addition to adverse climatic change, is a primary driver of yield loss in essential grain crops. An essentialplant breeding goal and the goal of this experiment was to develop drought-tolerant post-rainy season sorghum lines for higheryield under both well-water and water stress situations. Drought stress indices are one of the methods for identifying andselecting superior genotypes that are stable, high-yielding, and drought tolerant. The Plant Abiotic Stress Index Calculator(iPASTIC), an online software that calculates common stress tolerance and susceptibility indices for various crop traits, wasused to find superior genotypes using tolerance index (TOL), mean productivity (MP), harmonic mean (HM), yield stabilityindex (YSI), geometric mean productivity (GMP), stress susceptibility index (SSI), stress tolerance index (STI), relative stressindex (RSI), and yield index (YI). In this work, 45 Near isogenic lines (NILs) from crosses (SPV86 × E36-1, SPV570 × E36-1 andM35-1 × E36-1) were screened with the nine drought stress indices and all genotypes were differentiated under well-water andwater stress conditions. NILs 34, 21, 44, 7 and 9 were identified as the top five superior high yielding and drought tolerantgenotypes based on these indices, correlation and principal component analysis. These improved genotypes can be used infurther field evaluation and advanced breeding efforts to generate drought-tolerant cultivars.