Four QTL clusters containing major and stable QTLs for saturated fatty acid contents in a dense genetic map of cultivated peanut (Arachis hypogaea L.)

Abstract

Peanut is an important source of edible vegetable oils worldwide. Saturated fatty acid content is a key factor that affects the quality of peanut oil; thus, reducing its content is a key objective in peanut breeding. In this study, we constructed a dense genetic map of recombinant inbred line (RIL) population (Zhonghua 10 × ICG 12625) with 1443 SSR loci, covering a total length of 2279.10 cM. Using phenotypic data from three environments, we have identified 59 additive QTLs including eight stable ones and nine epistatic QTLs for various fatty acids. Combination of conditional and unconditional QTL analyses further revealed that there was a high genetic correlation between stearic acid and very longchain saturated fatty acids. In addition, four QTL clusters (CLB04-1, CLB04-2, CLB04-3, and CLB06) harboring major and stable QTLs for saturated fatty acids were identified, which explained 10.77-36.73%, 35.10-41.89%, 10.79-39.18%, and 4.85-20.32% phenotypic variations, respectively. The physical interval of four QTL clusters was located at pseudomolecule B04 and B06 of Arachis ipaensis, containing putative genes that encode enzymes and transcription factors involved in fatty acid biosynthesis pathways. This study comprehensively analyzed the genetic components that controlled saturated fatty acid profiles and identified four QTL clusters containing stable QTLs with large effects. Our results could provide a platform for further gene discovery and guide the development of markers for genomewide assisted selection of varieties with desired components of saturated fatty acids.

Dissection of the genetic basis of oil content in Chinese peanut cultivars through association mapping

“…The oil content showed an additive inheritance in crops [15,[39][40][41], which could facilitate pyramiding associated loci straightforward in the breeding program. In this study, associated markers were widely located on chromosome A03, A04, A08, A09, A10, B01, B06, B07, and B08 (Additional le 1: Table S1) based on the information from previous linkage maps and the physical location on genome [25,[42][43][44]. Compared with the previous results, chromosome A03, A04, A08, B06, B07, and B08 were also found to harbor QTLs for oil content [13,14,16].…”

“…The linkage disequilibrium (LD) was estimated using coe cients (r 2 ) of 280 SSR markers mapped on 20 linkage groups [25]. The average r 2 was 0.11 and almost 53.4% of the coe cients (r 2 ) showed statistically signi cant (P < 0.01).…”

Dissection of the genetic basis of oil content in Chinese peanut cultivars through association mapping

“…The linkage disequilibrium (LD) was estimated using coefficients (r 2 ) of 280 SSR markers mapped on 20 linkage groups [25]. The average r 2 was 0.11 and almost 53.4% of the coefficients (r 2 ) showed statistically significant (P < 0.01).…”

Dissection of the genetic basis of oil content in Chinese peanut cultivars by association mapping

“…The allele number, major allele frequency, genetic diversity and polymorphism information content (PIC) were calculated using PowerMarker V3.25 software [52]. The number of subgroups of this peanut panel was estimated using STRUCTURE software V2.1 based on the model-based Bayesian clustering method [53]. To determine an optimum number of subgroups (K), five independent runs were performed to estimate each K values from 1 to 10 for each accession.…”

“…Associations between SSR markers and the trait of oil content were performed using TASSEL software based on a Q+K mixed linear model [55]. The population structure (Q) was obtained from modelbased program STRUCTURE V2.1 [53]. The pairwise kinship matrix (K) was calculated using SPAGeDi software [56] Declarations Ethics approval and consent to participate…”