Resistance and tolerance are different plant defense mechanisms against herbivores. In this study, four compensatory growth (tolerance) indexes-the ratios of treatment to control for plant height (RPH), branching number of the stem (RBN), seed number per plant (RSN), and seed weight per plant (RSW)-and three resistance indexes-larval weight (LW), pupal weight (PW), and larva-consumed leaf weight (LCL)-were used to evaluate soybean (Glycine max (L.) Merr) defense against common cutworm (CCW; Spodoptera litura Fabricius). The phenotypic variations of seven traits among 170 accessions were significant (ANOVA, P \ 0.01). Five of the seven traits had a large variation ([20 %) in this population. The decay distance of linkage disequilibrium was approximately 639 kb on average in intrachromosomal regions. Approximately 80 % of the intervals between two neighboring single-nucleotide polymorphisms were less than 600 kb. The natural population was divided into two subpopulations with little population structure. The genetic relationship among the accessions was distant. Fifty-one quantitative trait loci (QTLs) were significantly associated with the seven traits: six for RPH, nine for RBN, seven for RSN/RSW, one for RBN/RSN/RSW, six for LW, nineteen for LCL, and three for PW (-Log P C 2.00, P B 0.01). Single QTLs contributed 2.8-11 % of the phenotypic variance. Three QTLs were co-associated with soybean resistance and compensatory growth at the 0.05 significant level. Of these three QTLs, the qSCCW18-3 located in the promoter sequence of the soybean Rubisco activase b subunit gene (GmRCAb) and its resistance allele reduced LW and increased plant height.
We used 135 genome-wide simple sequence repeat (SSR) markers to assess genetic diversity, population structure and linkage disequilibrium (LD) of 196 soybean landraces. On the basis of estimated population structure, we conducted association mapping for soybean resistance to common cutworm (CCW) using genomic-wide mapping strategies and detected the elite alleles of soybean resistance to CCW, along with their carriers. In addition to wide geographic origin, the population showed extensive genetic variation, and 17.9% of the SSR pairs were in LD (with D'>0, P<0.05).The extent of LD was > 6.61 cM with genetic distance of locus pairs for the loci in the same linkage group (LG). Association analysis revealed 7 SSRs associated with soybean resistance to CCW (P<0.01): 4 accounted for >10% of the total genetic variation for resistance; 6 located in the linkage groups reported to be related to soybean resistance to insects. Allele effect analysis revealed that the alleles related to larval weight of CCW mainly had a negative effect, the allele Sat_334-A208 showing the largest negative effect (43.9%). The alleles related to leaf consumption of single larva (LCL) and pupal weight (PW) of CCW mainly had a positive effect, the allele Satt199-A186 showing the largest positive effect for LCL (36.4%) and the allele Sat_320-A286, the largest positive effect for PW (31.4%).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.