Linkage Mapping Reveals QTL for Flowering Time-Related Traits under Multiple Abiotic Stress Conditions in Maize

Abstract

Variation in flowering plays a major role in maize photoperiod adaptation during long-term domestication. It is of high value to investigate the genetic basis of maize flowering under a wide range of environmental conditions in order to overcome photoperiod sensitivity or enhance stress tolerance. A recombinant inbred line (RIL) population derived from a cross between Huangzaosi and Mo17, composed of 121 lines and genotyped by 8329 specifically developed markers, was field evaluated in two consecutive years under two planting densities (67,500 and 120,000 plants ha−1) and two water treatments (normal irrigation and drought stress at the flowering stage). The days to silking (DTS), days to anthesis (DTA), and anthesis to silking interval (ASI) were all evaluated. Within the RIL population, DTS and DTA expanded as planting density and water deficit increased. For DTA, DTS, ASI, and ASI-delay, a total of 22, 17, 21, and 11 QTLs were identified, respectively. More than two significant QTLs were identified in each of the nine chromosomal intervals. Under diverse conditions and locations, six QTLs (quantitative trait locus) for DTS and DTA were discovered in Chr. 8: 118.13–125.31 Mb. Three chromosome regions, Chr. 3: 196.14–199.89 Mb, Chr. 8: 169.02–172.46 Mb, and Chr. 9: 128.12–137.26 Mb, all had QTLs for ASI-delay under normal and stress conditions, suggesting their possible roles in stress tolerance enhancement. These QTL hotspots will promote early-maturing or multiple abiotic stress-tolerant maize breeding, as well as shed light on the development of maize varieties with a broad range of adaptations.

The battle of crops against drought: Genetic dissection and improvement

“…Drought at the reproductive stage (flowering) significantly reduces the panicle number and yield of crop plants (Barnabás et al, 2008; Melandri et al, 2020). Many studies have been undertaken to identify quantitative trait loci (QTLs) for drought resistance by imposing drought treatment at the reproductive stage in the field (Vikram et al, 2011; Xue et al, 2013; Melandri et al, 2020; Chong et al, 2022; Leng et al, 2022). This review explores recent advances in mining drought‐responsive elements and uncovering the molecular mechanisms of drought responses in crop plants.…”

Evaluation of the growth and tolerance of maize lines under aluminum stress

“…The flowering phase is inhibited when Al mostly bound phosphorus to form insoluble phosphate in Al stress. In addition, water availability due to the bonding of Al and other metals in acidic soils causes dehydration of plant tissue; this affects cell division and tissue expansion, leading to the inhibition of pollen shedding and silk elongation (Opala 2017;Leng et al 2022).…”