Abstract
Drought is a major abiotic stress factor limiting maize production, and elucidating the genetic control of root system architecture and plasticity to water-deficit stress is a crucial problem to improve drought adaptability. In this study, 13 root and shoot traits and genetic plasticity were evaluated in a recombinant inbred line (RIL) population under well-watered (WW) and water stress (WS) conditions. Significant phenotypic variation was observed for all observed traits both under WW and WS conditions. Most of the measured traits showed significant genotype–environment interaction (GEI) in both environments. Strong correlations were observed among traits in the same class. Multi-environment (ME) and multi-trait (MT) QTL analyses were conducted for all observed traits. A total of 48 QTLs were identified by ME, including 15 QTLs associated with 9 traits showing significant QTL-by-Environment interactions (QEI). QTLs associated with crown root angle (CRA2) and crown root length (CRL1) were identified as having antagonistic pleiotropic effects, while 13 other QTLs showed signs of conditional neutrality (CN), including 9 and 4 QTLs detected under WW and WS conditions, respectively. MT analysis identified 14 pleiotropic QTLs for 13 traits, SNP20 (1@79.2 cM) was associated with the length of crown root (CR), primary root (PR), and seminal root (SR) and might contribute to increases in root length under WS condition. Taken together, these findings contribute to our understanding of the phenotypic and genotypic patterns of root plasticity in response to water deficiency, which will be useful to improve drought tolerance in maize.
Highlights
Maize (Zea mays L.) is the most widely grown staple food, feed, and industrial crop, and it plays a critical role in supporting the growing world population
Maize plants were grown under WW and water-stressed (WS) conditions in a greenhouse, and seven root traits, including crown root (CRA, CRD, CRL, and crown roots (CRN)), PRL, and seminal root number (SRL and SRN), and six shoot traits, including plant height (PH), leaf traits (LL and LW), shoot biomass (SDW and SFW), and SPAD, were evaluated three times
Water stress had the greatest influence on SFW and SPAD; the values for these parameters were reduced by 16.62 and 17.96%, respectively
Summary
Maize (Zea mays L.) is the most widely grown staple food, feed, and industrial crop, and it plays a critical role in supporting the growing world population. Maize has become one of the most productive crops after intensive improvement, the yield of maize is frequently limited by various biotic and abiotic stress factors, such as drought, salinity, high and low temperatures, nutrient deficiencies, disease, and insect pests. Of these stresses, maize is most susceptible to drought (Araus et al, 2012). Maize Root Plasticity to Drought various adaptive strategies. Dissecting the genetic basis of such traits are essential for the development of more drought-tolerant maize cultivars
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