Differential response of finger millet accessions to contrasting saline water levels and irrigation regimes under desert conditions

TL;DR

This study identifies resilient finger millet varieties that can thrive under saline and water-scarce conditions in desert environments.

Contribution

A novel selection framework for climate-resilient finger millet using multi-trait ideotype distance index and validation under combined stress regimes.

Findings

Elite finger millet accessions showed a 167% genetic gain in grain yield under high salinity.

Managed water-deficit stress caused a 42.7% yield loss compared to 20.4% under saline irrigation.

Dry fodder yield remained stable across saline and drought conditions, identifying IE 4028 and IE 4570 as resilient parental lines.

Abstract

Water salinity and scarcity constitute major limitations to crop production in arid and semi-arid regions. Introduction of nutritious and stress-tolerant underutilized crops is a promising approach for dietary enrichment, cropping system diversification, remediation of marginal and degraded lands, and building climate resilience. The primary objectives of this study were to investigate the effect of water salinity and managed water-deficit stress on grain and fodder yield, identify multi-trait ideotypes, and validate the stability and genetic gain in finger millet ideotypes over a 2-year period. A total of 80 finger millet accessions were evaluated under fresh water (0 dS/m) and two saline irrigation water (6 and 10 dS/m) in Dubai during the 2020/2021 cropping season. Validation of a selected elite subset was conducted under a combination of optimum, salinity, and drought-stress regimes (0 dS/m, 6 dS/m, 10 dS/m, and 50% irrigation) during the 2021/2022 cropping season. Initial analysis showed a grain yield (GYLD) reduction of 87% under 10 dS/m saline irrigation water compared with the control, and the genotype-by-treatment (G × T) interaction revealed highly significant effects for GYLD. Using multi-trait genotype–ideotype distance index (MGIDI), 20 elite accessions were identified, demonstrating a remarkable increase in mean GYLD under high saline irrigation water, corresponding to a genetic gain of 167% over the reference population mean. Validation trials confirmed the success of the selection by showing a non-significant G × T for GYLD and dry fodder yield (DFYLD) across the four validation treatments, alongside a significant increase in heritability (H2) for GYLD from 0.60 to 0.78. Comparative analysis revealed that managed water-deficit stress was the most limiting factor for GYLD in the elite subset, causing an average loss of 42.7% compared to 20.4% under high saline water irrigation. However, DFYLD displayed exceptional stability across both saline water and water-deficit stress types. The comparative analysis presented in Venn diagrams ultimately identified a core group of stable, broadly adapted accessions, including IE 4028 and IE 4570, which are recommended as high- impact parental lines for combined stress tolerance. These findings establish a reliable selection framework for enhancing the climate-resilience of underutilized crops in marginal environments.

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