Evaluating Sorghum Varieties for Low Nitrogen Tolerance Based on Yield

Jim Crocker
15th June, 2024

Evaluating Sorghum Varieties for Low Nitrogen Tolerance Based on Yield

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Haramaya University studied 300 sorghum landraces to find those that can handle nitrogen stress
  • They identified sorghum genotypes ETSL101255, ETSL101006, and ETSL101258 as top performers under nitrogen stress
  • Genotypes ETSL100292, ETSL100539, and ETSL100890 were found to be susceptible to nitrogen stress
Nitrogen stress significantly limits the productivity of sorghum crops, a staple food and fodder source in many parts of the world. To address this issue, researchers at Haramaya University conducted a study to identify sorghum genotypes that are well-suited to nitrogen stress conditions[1]. They evaluated 300 sorghum landraces and two standard checks (KS78 and BCK60) using yield-based indices under both nitrogen stress and ideal conditions over two years. The study used a split-plot design with randomized complete block design (RCBD) and two replications. Nitrogen treatments were assigned to the main plots, while sorghum genotypes were assigned to the subplots. Fourteen nitrogen stress screening indices were computed using grain yield, including the yield stability index (YSI), stress tolerance index (STI), and low nitrogen tolerance index (LNTI). The yield under optimal and stress conditions was significantly positively correlated with indices such as the harmonic mean (HM), mean productivity (MP), geometric mean productivity (GMP), and modified stress tolerance index (KSTI). Cluster analysis, PCA biplot, and 3D biplot classified the genotypes into three groups: nitrogen stress tolerant, nitrogen stress susceptible, and poor performers under both environments. Using indices like STI, GMP, and MP, the study identified genotypes such as ETSL101255, ETSL101006, and ETSL101258 as top nitrogen stress tolerant, while genotypes like ETSL100292, ETSL100539, and ETSL100890 were identified as susceptible. This study builds on previous research that explored natural genetic variability in sorghum for improved nitrogen use efficiency (NUE)[2]. Earlier findings indicated significant variations in yield traits under different nitrogen regimes, confirming the availability of native genetic variability in sorghum. The integration of high-throughput phenotyping and next-generation sequencing (NGS)-based genotyping helped identify promising genotypes with consistent performance under varying environments. The current study at Haramaya University further refines this by using specific yield-based indices to classify genotypes based on their nitrogen stress tolerance. Additionally, the study aligns with findings from research on Ethiopian sorghum accessions, which revealed high genetic diversity and the presence of rare natural variations[3]. This diversity is crucial for developing genotypes that can adapt to different environmental stresses, including nitrogen stress. The identification of candidate genes associated with abiotic stress tolerance in Ethiopian sorghum germplasm also complements the current study's focus on nitrogen stress. Moreover, the study's approach to evaluating nitrogen stress tolerance through multiple indices provides a comprehensive understanding of how different genotypes perform under stress. This methodology is consistent with previous research that emphasized the importance of integrated strategies, including phenotyping and genotyping, to improve NUE in crops[2]. The findings from this study have practical implications for sorghum breeding programs. By identifying nitrogen-efficient genotypes, breeders can develop new sorghum varieties that maintain high yields even under nitrogen stress conditions. This is particularly important for regions where nitrogen fertilizer is either too expensive or environmentally unsustainable. In summary, the study conducted by Haramaya University provides valuable insights into the genetic basis of nitrogen stress tolerance in sorghum. By using yield-based indices and advanced statistical methods, the researchers have identified genotypes that can thrive under nitrogen stress, thereby contributing to the development of more resilient sorghum varieties. This research not only builds on previous studies but also offers a clear path forward for improving sorghum productivity in nitrogen-limited environments.

AgricultureGeneticsPlant Science

References

Main Study

1) Yield -based evaluation of low nitrogen tolerance indices for screening of [Sorghum bicolor (L.) Moench] genotypes

Published 14th June, 2024

https://doi.org/10.1007/s44279-024-00038-x

Related Studies

2) Nitrogen Use Efficiency in Sorghum: Exploring Native Variability for Traits Under Variable N-Regimes.

https://doi.org/10.3389/fpls.2021.643192

3) A comprehensive phenotypic and genomic characterization of Ethiopian sorghum germplasm defines core collection and reveals rich genetic potential in adaptive traits.

https://doi.org/10.1002/tpg2.20055


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