Morpho-physio-biochemical and gene expression profiling of drought-tolerant sugarcane genotypes (Saccharum hybrids).

Abstract

Background: In this study, we assess how well 10 types of sugarcane (Saccharum spp. L.) can handle drought and produce sugar based on water loss from the crop to help with future breeding programs. The experiment entails subjecting the plants at 120 days after planting them in the greenhouse for two seasons to water treatments, using three levels of irrigation stress for the plants, and some morphological, physiological, and biochemical parameters were studied, and finally, we employed gene expression techniques such as quantitative real-time polymerase chain reaction (Q-RT-PCR).

Results: Ten sugarcane genotypes were exposed to three stressed water treatments in the current investigation based on crop evapotranspiration. The results demonstrated that morphological measurements revealed highly significant variations in the majority of genotypes under the most severe water deficit stress, which was 62.5% of ET₀. Significant variations are evident in physiological parameters (relative water content and chlorophyll), with the majority of genotypes exhibiting high values for the parameters under investigation (G.2000-3 and G.2004-27). For biochemical measurements, the genotypes with the highest excellent values were G.2003-49 and G.2000-3 for peroxidase and G.84-47 for proline concentration and total phenolic compounds. However, at the molecular level, the genotypes K.81113 and G.2004-27 outperformed the others in sustaining an increase in sucrose synthase and proline oxidase (POX). Regarding sugarcane production and yield components, the genotype that was most tolerant under the maximum stressed irrigation level of 62.5% of ET₀ was G.99-103. This genotype exhibited good values for the examined parameters under all stressed conditions, including 1 (ScSuSy1) gene. Genotypes G.2009-11, G.2003-47, G.2003-49, and M.35-15 contributed the most to principal component analysis, accounting for 62.5% of ET₀.

Conclusion: The most promising genotypes for drought tolerance, increased capacity for sucrose accumulation, and potential application in breeding programs are G.2004-27, K.81113, G.2000-3, G.99-103, and G.2009-11, based on all the data obtained at all the parameters evaluated.