Genotypic diversity in root architectural traits and adaptation of wheat to water limited enviromental

Abstract

In wheat, the seminal root angle is representative of the root architecture of the adult plant, making it a useful tool because it is a trait that can be easily phenotyped in the early stages of plant development. A narrow seminal root angle can increase access to residual moisture at depth, particularly under terminal drought conditions. The objective of this work is to evaluate the genetic divergence of root architecture traits and to present a high-throughput root architecture phenotyping method that can be easily implemented in breeding programs. Wheat seedlings were evaluated for root architecture in a system of hanging file folders covered with germination paper. For each plant, measurements were taken of the angle between the first two seminal roots, length, and number of seminal roots. Based on the drought-tolerant control BRS 404, which presented an angle of the first pair of seminal roots of 54.73°, roots with an angle less than 60° were classified as narrow angles and were selected as standard selection criteria. The distances between accessions ranged from 0.165 to 28.64, allowing the formation of eight diversity groups. The traits that contributed most to the divergence were plant score (69.48%) and the angle of the first pair of seminal roots (24.75%). The transgenic lines Cadenza HB4® x BRS 264 and Cadenza HB4® x BRS 404, cultivars and lines BRS 404 and BR_18 UB2.323.916, UB2.323.907, UB2.323.917, UB2.323.919, with a narrow angle between the first pair of seminal roots and a plant score above 5, were selected as potential for planting under water-restricted environmental conditions. The method allowed high differentiation between genotypes and is therefore suitable for large-scale screening with high throughput of root architecture traits.