Location: Invasive Species and Pollinator HealthTitle: Quantitative trait locus mapping for carbon isotope ratio and root pulling force in canola
|MEKONNEN, MELAKU - Syngenta Crop Protection|
|MULLEN, JACK - Colorado State University|
|ASSEFA, YARED - Kansas State University|
|MCKAY, JOHN - Colorado State University|
|BYRNE, PATRICK - Colorado State University|
Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2020
Publication Date: 10/4/2020
Citation: Mekonnen, M., Mullen, J., Seshadri, A.H., Assefa, Y., Mckay, J., Byrne, P. 2020. Quantitative trait locus mapping for carbon isotope ratio and root pulling force in canola. Agrosystems, Geosciences & Environment. 3(1):e20083. https://doi.org/10.1002/agg2.20095.
Interpretive Summary: Plant responses to drought stress can be categorized into three major mechanisms: dehydration tolerance, dehydration avoidance and drought escape, of which the last two are relevant to plant breeding. Drought escape is when the plant completes its life cycle before the onset of drought, a strategy that allows the plants to survive while reducing productivity. Drought escape strategy reduces or eliminates flowering, distinctly impacting pollinators that depend on flowers for nutrition. Dehydration avoidance, on the other hand, occurs when plants maintain their water status while under low air or soil moisture stress by maximizing water uptake by the roots. Root Pulling Force is a trait that is associated with dehydration avoidance and plant productivity. This study determines the genetics of RPF and dehydration avoidance in canola, a plant that benefits from honey bee pollination, the pollen from which is highly nutritive for bees.
Technical Abstract: Carbon isotope ratio (d13C) and root pulling force (RPF) are associated with dehydration avoidance in plants. Carbon isotope ratio measures the efficiency of carbon gain relative to water loss, while RPF, the vertical force required to pull plants from the ground, is an indirect estimate of root-related dehydration avoidance capacity. To determine quantitative trait loci (QTL) controlling these traits in canola (Brassica napus L.), a mapping population derived from a yellow by black seeded cross was evaluated in 2011 and 2012 in Fort Collins, Colorado. The split-plot experiment had two moisture regimes as the main plot factor, and 148 doubled haploid lines as the subplot factor, replicated three times. Analysis of variance indicated highly significant (P<0.01) variation among genotypes for d13C, RPF, days to flower, and several morphological and agronomic traits. Carbon isotope ratio showed significant positive correlations (P<0.01) with days to flower in both moisture treatments and fresh biomass in the dry treatment of 2011. The RPF was consistently correlated with plant height (P<0.01) and fresh biomass (P<0.05) in all environments. In 2011, QTL were detected on chromosomes A09 and C08 for d13C and on chromosomes A05, C01, C04, and C08 for RPF. The QTL for d13C, RPF, and plant height were co-localized on C08. In 2012, QTL were detected on A02 for d13C and on C01 and C08 for RPF. Moderate heritability and low QTL x environment interaction for d13C and RPF were observed, suggesting that if validated, markers for these traits could be used in marker-assisted selection.