Comparative Analysis of Drought Tolerance in Traditional versus Modern Maize Varieties

Thesis Abstract

Drought stress remains a major constraint to maize production globally, particularly in regions with increasing climatic variability, necessitating a comparative evaluation of traditional and modern maize varieties’ drought tolerance to inform sustainable crop improvement strategies. This study aims to analyze and compare the physiological, morphological, and yield-related responses of traditional versus modern maize varieties under drought stress conditions to identify traits associated with drought resilience and to inform breeding programs. The specific objectives include quantifying the variation in drought tolerance traits between the two categories, determining the relationship between physiological indicators and yield performance, and assessing the genetic variability underlying drought response. A quantitative research design was adopted, utilizing a factorial experiment conducted under controlled field conditions supplemented by simulated drought stress treatments that mimic realistic drought scenarios. The population comprised maize varieties categorized as traditional (landraces and farmer-preferred indigenous strains) and modern (conventionally bred hybrids and commercial stocks). A total of 20 maize varieties, equally divided between traditional and modern groups, were selected based on popularity and previous performance reports. A sample size of 300 plants was obtained, with random complete block design implemented to minimize environmental variability. Data collection instruments included portable photosynthesis meters, soil moisture sensors, and high-throughput phenotyping tools, alongside standard agronomic measurement sheets. Key physiological parameters measured encompassed stomatal conductance, chlorophyll content, and relative water content; morphological traits included root and shoot lengths; and yield components such as cob weight and kernel number per plant. Data analysis involved descriptive statistics to summarize trait variability, followed by Analysis of Variance (ANOVA) to compare means across variety groups. Multivariate techniques, including Principal Component Analysis (PCA), were employed to identify key traits associated with drought tolerance. Regression analysis was used to establish relationships between physiological parameters and yield outcomes. The study also applied the Stress Tolerance Index (STI) to rank varieties based on their drought resilience, and genetic diversity assessments were conducted through molecular marker analysis to explore underlying variability. It is anticipated that results will reveal significant differences in drought response traits, with traditional varieties potentially exhibiting superior stomatal regulation and water retention capacity, while modern varieties may demonstrate higher yield potential under optimal conditions but increased susceptibility under drought stress. The findings are expected to highlight specific traits—such as enhanced root system architecture and efficient water use—that correlate strongly with drought resilience, and to identify genetically diverse varieties with superior adaptive traits. The study will contribute to the understanding of the physiological and genetic bases of drought tolerance in maize, filling critical gaps in knowledge regarding the comparative resilience of traditional versus modern cultivars. The main conclusion will likely suggest that integrating drought-tolerance traits from traditional landraces into modern breeding programs could enhance resilience without compromising yield potential. Recommendations will emphasize the valorization of traditional germplasm in crop improvement and advocate for the development of drought-adapted hybrid varieties through marker-assisted selection. The findings aim to inform policymakers and breeders on effective strategies for developing climate-resilient maize cultivars, ultimately contributing to food security amid increasing climatic uncertainties.