QTLs for Seed Vigor-Related Traits Identified in Maize Seeds Germinated under Artificial Aging Conditions

Abstract

High seed vigor is important for agricultural production due to the associated potential for increased growth and productivity. However, a better understanding of the underlying molecular mechanisms is required because the genetic basis for seed vigor remains unknown. We used single-nucleotide polymorphism (SNP) markers to map quantitative trait loci (QTLs) for four seed vigor traits in two connected recombinant inbred line (RIL) maize populations under four treatment conditions during seed germination. Sixty-five QTLs distributed between the two populations were identified and a meta-analysis was used to integrate genetic maps. Sixty-one initially identified QTLs were integrated into 18 meta-QTLs (mQTLs). Initial QTLs with contribution to phenotypic variation values of R2>10% were integrated into mQTLs. Twenty-three candidate genes for association with seed vigor traits coincided with 13 mQTLs. The candidate genes had functions in the glycolytic pathway and in protein metabolism. QTLs with major effects (R2>10%) were identified under at least one treatment condition for mQTL2, mQTL3-2, and mQTL3-4. Candidate genes included a calcium-dependent protein kinase gene (302810918) involved in signal transduction that mapped in the mQTL3-2 interval associated with germination energy (GE) and germination percentage (GP), and an hsp20/alpha crystallin family protein gene (At5g51440) that mapped in the mQTL3-4 interval associated with GE and GP. Two initial QTLs with a major effect under at least two treatment conditions were identified for mQTL5-2. A cucumisin-like Ser protease gene (At5g67360) mapped in the mQTL5-2 interval associated with GP. The chromosome regions for mQTL2, mQTL3-2, mQTL3-4, and mQTL5-2 may be hot spots for QTLs related to seed vigor traits. The mQTLs and candidate genes identified in this study provide valuable information for the identification of additional quantitative trait genes.

Molecular approaches for genetic improvement of seed quality and characterization of genetic diversity in soybean: a critical review

“…Specific bands produced by SSR markers Satt371, Satt453 and Satt618 make them candidate markers for linkage with seed storability and testa colour (Hosamani et al 2013). The last decade has also seen research directed towards the inference of the genetic basis of seed deterioration through investigation of quantitative trait loci associated with seed longevity (Han et al 2014). Seed ageing is a complex biological trait and difficult to monitor.…”

Genetic Modification for Improving Seed Vigor Is Transitioning from Model Plants to Crop Plants

“…This trait is controlled by many QTLs that are located on different chromosomes, as found in the model plant Arabidopsis (Clerkx et al, 2004) and in crop plants such as rice (Cui et al, 2002; Miura et al, 2002), Medicago truncatula (Vandecasteele et al, 2011), and maize (Han et al, 2014) and is also affected by environmental factors during seed development, harvest, and storage.…”

Biology of Seed Vigor in the Light of -omics Tools

“…From many seed deterioration experiments, QTLs of seed longevity traits like LD 50 in Arabidopsis seeds [21], germination of aged wheat seeds [48,49] and half-life (P 50 ) of aging barley seeds [50] have been mapped and linked to various genes. For the germination vigor of seeds, several seed priming experiments have found QTLs for germination of maize seeds [51] and QTLs for 30 vigor traits of rice seeds [52] to mention a few. These studies also provided useful information on chromosome regions and putative genes controlling various seed vigor traits in different crops.…”

“…Nagel et al [50] also reported large QTL effects associated with seed half-life (P 50 ) on chromosomes 5 and 7 in a doubled haploid mapping population of barley. Han et al [51] found 65 QTLs in two maize populations mapped using single-nucleotide polymorphism (SNP) markers to four seed vigor traits under four germination treatment conditions. Integrating the QTLs into 18 meta-QTLs (mQTLs), 23 candidate genes associating with seed vigor phenotype coincides with 13 mQTLs controlling protein metabolism and the glycolytic pathway.…”