Drought-Induced Changes in Root and Shoot Characteristics of Alfalfa (Medicago spp.) Genotypes
Abstract
Alfalfa (Medicago sativa L.) is a forage legume that is commonly grown because of its productivity, quality, and ability to thrive in dry conditions. This study looks at how different alfalfa genotypes respond to drought stress with focus on shoot and root characteristics and biomass partitioning. The study is a randomized complete block design experiment under greenhouse conditions with two watering treatments: an irrigated control and a water deficit treatment. Each treatment was replicated three times. The study recorded a number of traits including plant height, shoot and root biomass, root length, root volume, total biomass, root-to-shoot ratio, and root biomass. The significant variation between the genotypes for the traits measured in both the irrigated and drought-stressed conditions. Drought had a large negative impact on plant height, shoot and root biomass, total biomass, and root volume, with reductions of 10.71(%), 51.63(%), 51.28(%), 51.44(%) and 22.04(%), respectively. With drought, the root-to-shoot ratio and root-to-total ratio increased by 2.41(%), and 1.30(%), respectively, suggesting more root biomass was allocated under stressed conditions. There was a 43.85(%) increase of root biomass in the deeper parts of the soil, suggesting an improved ability to gain water in dry conditions. Genotypes such as ALF–CRO-6, ALF-CRO-7, ALF-CRO-5, and AUS-ALF-17 of root and biomass traits showed the most drought tolerance. Overall, the study suggested that in alfalfa, drought tolerance is highly dependent on root architecture and biomass. Genotypes maintaining higher root biomass, deeper rooting patterns, and greater root-to-shoot ratios under stress conditions may serve as valuable genetic resources for developing drought-resilient alfalfa cultivars. Thus, the study helped us to identify promising lines for tolerance towards abiotic stress (drought stress) which could be used in future breeding programs.