Genetic analysis of seedling root traits reveals the association of root trait with other agronomic traits in maize

Abstract

BackgroundRoot systems play important roles in crop growth and stress responses. Although genetic mechanism of root traits in maize (Zea mays L.) has been investigated in different mapping populations, root traits have rarely been utilized in breeding programs. Elucidation of the genetic basis of maize root traits and, more importantly, their connection to other agronomic trait(s), such as grain yield, may facilitate root trait manipulation and maize germplasm improvement. In this study, we analyzed genome-wide genetic loci for maize seedling root traits at three time-points after seed germination to identify chromosomal regions responsible for both seedling root traits and other agronomic traits in a recombinant inbred line (RIL) population (Zong3 × Yu87–1).ResultsEight seedling root traits were examined at 4, 9, and 14 days after seed germination, and thirty-six putative quantitative trait loci (QTLs), accounting for 9.0–23.2% of the phenotypic variation in root traits, were detected. Co-localization of root trait QTLs was observed at, but not between, the three time-points. We identified strong or moderate correlations between root traits controlled by each co-localized QTL region. Furthermore, we identified an overlap in the QTL locations of seedling root traits examined here and six other traits reported previously in the same RIL population, including grain yield-related traits, plant height-related traits, and traits in relation to stress responses. Maize chromosomal bins 1.02–1.03, 1.07, 2.06–2.07, 5.05, 7.02–7.03, 9.04, and 10.06 were identified QTL hotspots for three or four more traits in addition to seedling root traits.ConclusionsOur identification of co-localization of root trait QTLs at, but not between, each of the three time-points suggests that maize seedling root traits are regulated by different sets of pleiotropic-effect QTLs at different developmental stages. Furthermore, the identification of QTL hotspots suggests the genetic association of seedling root traits with several other traits and reveals maize chromosomal regions valuable for marker-assisted selection to improve root systems and other agronomic traits simultaneously.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1383-5) contains supplementary material, which is available to authorized users.

Root Growth Adaptation to Climate Change in Crops

“…The potential of roots to boost crop productivity has been establish in several studies where correlations between root traits and yield have been determined (Bray and Topp, 2018;Robinson et al, 2018;Jia et al, 2019). This close relation is confirmed by the co-ocurrence of QTLs for root traits and grain yield and other agronomic traits associated to productivity in different crops (Maccaferri et al, 2016;Ju et al, 2018). Root traits like deep rooting or root angle seem to increase vegetative growth and subsequent grain filling but are also context dependent.…”

Phenotypic Diversity for Root Traits and Identification of Superior Germplasm for Root Breeding in Watermelon

“…2) suggests presence of quantitative inheritance of the examined root traits and the involvement of multiple loci underlying these traits. Previous studies have reported numerous genetic loci controlling root length and surface area in maize, wheat, and common bean (Bhatta et al, 2019;Ju et al, 2018;Lin et al, 2019;Polania et al, 2017;Wang et al, 2019). The trait distribution patterns generated in this study will serve as a benchmark in future genetic studies seeking to characterize the genetic basis and inheritance of root phenotypes in watermelon.…”

Identification of Quantitative Trait Loci Controlling Ethylene Production in Germinating Seeds in Maize (Zea mays L.)

“…Germination assays of the 14 inbred lines. The seeds were surface-sterilized as described previously 63 , wiped dry with paper towels, and then stored in gas-tight containers with silica gel beads for three days before the experiments. For the germination assays of the 14 inbred lines under normal conditions or DE3 and BY815 under chemical treatment, the seeds were immersed in distilled water, 100 µM 1-aminocyclopropane-1-carboxylic acid (ACC) (Sigma-Aldrich, St. Louis, MO), 100 μM silver nitrate (Ag + ) (Sigma-Aldrich), or 10 μM aminoethoxyvinylglycine (AVG) (Sigma-Aldrich) in Petri dishes containing two sheets of moist filter papers on the bottom and two layers of wet gauze on top of the seeds.…”

“…Methods for the evaluation of three traits in the DE3 × BY815 RIL population and the two parental lines. The seeds were surface-sterilized as described previously 63 , wiped dry with paper towels, and then stored in gas-tight containers with silica gel beads for three days before the experiments. For each sample, the weight (g) of 20 dry seeds was determined.…”