The Changes in Coleoptile Length and Root System Architecture During Wheat Polyploidization

Abstract

Polyploidy, the doubling of chromosomes, has significantly shaped the evolution of flowering plants, including wheat. Yet, its impact on crucial traits like coleoptile length and root development remains unclear. This study compared these traits in wheat varieties with different ploidy levels, focusing on coleoptile length and root system diversity. Five genotypes/cultivars were used for each of einkorn (Triticum monococcum), durum (landraces and cultivars, Triticum durum and Triticum turgidum), and bread wheat (Triticum aestivum). The coleoptile length and root morphological measurement procedures were conducted using a blotter-paper germination protocol. The experiment was designed according to a completely randomized design with three replications. The results revealed that domestication and selection pressures have influenced wheat's coleoptile length and certain root system characteristics. Interestingly, polyploidy appears to have a mixed bag of effects. It enhances root angle and seminal root numbers. However, total root length and coleoptile length are negatively affected. Importantly, the longest root remains unaffected. This divergence in root traits highlights the complex interplay between polyploidy and plant morphology. Understanding these trade-offs is crucial for plant breeders. To combine polyploidy's desirable robustness with optimal root systems, wild relatives and modern wheat varieties need to be strategically integrated into breeding programs. This will allow for the recovery of valuable traits that separated during wheat's evolutionary journey.