Genetic Mapping of Agronomic Traits Using Recombinant Inbred Lines of Soybean

Abstract

Many agronomic traits of interest to plant breeders are quantitative. Recombinant inbred (RI) lines are particularly useful in genetic mapping studies of quantitative traits. A recombinant inbred population was derived from the Glycine max (L.) Merr. parents ‘Minsoy’ and ‘Noir 1’. This soybean population was used to investigate the genetic basis of several agronomic traits: days to flower (Rl), days to maturity (R8), reproductive period (RS‐R1), plant height, lodging score, height divided by lodging (the ability of tall plants to stand upright), seed protein content, seed oil content, seed size, yield, seed number, yield divided by height (the yield from short plants), leaf width, leaf length, and leaf area. In this RI population, transgressive segregation was observed for all of these traits. As expected, height and lodging were correlated, as were height and maturity; height and maturity with yield; and leaf length and width with leaf area. Height divided by lodging and yield divided by height showed little correlation with other traits, indicating that these traits measured new plant phenotypes. A genetic map was constructed for this population, with restriction fragment length polymorphism markers, simple sequence repeat markers and classical markers. Approximately 2000 cM of linkage was defined. The data were used to identify quantitative trait loci (QTLs) by linking quantitative phenotypes to qualitative genetic markers. for many traits, a few QTLs accounted for a large proportion of the variation observed. QTLs for most of the traits were associated with three linkage groups, often with the same genetic locus within the linkage group. At the level of resolution of the genetic map for this population, it was not possible to determine whether these QTLs have pleiotrophic effects or are clusters of separate, tightly linked genes. The data suggest that separation of QTLs for different traits (such as maturity or lodging and yield) may be difficult, but that this RI population will be useful in resolving questions concerning marker assisted selection of quantitative traits.

A new integrated genetic linkage map of the soybean

“…The University of Utah 'Minsoy' 'Archer' (MA) and 'Archer' 'Noir 1' (AN) RIL populations were described by Mansur et al (1995Mansur et al ( , 1996. Newly developed SSRs were mapped to MA, MN, and/or NA populations, and then JoinMap analysis was used on the five populations.…”

National Science Foundation-Sponsored Workshop Report. Draft Plan for Soybean Genomics

“…In spite of its polyploid origin, the soybean composite genetic map is well developed. The classical map contains only 67 loci on 19 linkage groups (Hedges and Palmer, 1993) (Mansur et al, 1996); a University of Nebraska population derived from Clark 3 Harosoy (Shoemaker and Specht, 1995); a USDA/ Iowa State University population, an F2-derived mapping population from A81-356022 (G. max) 3 PI468.916 (G. soja), with 59 F2 plant derivatives (Shoemaker and Olson, 1993;Shoemaker and Specht, 1995;Keim et al, 1996) Marek and Shoemaker, 1997;Danesh et al, 1998;Tomkins et al, 1999;Meksem et al, 2000 The soybean genome comprises about 1.1 Mb/Cvalue (Arumuganathan and Earle, 1991). This makes it about seven and one-half times larger than the genome of Arabidopsis but less than one-half the size of the maize genome (Arumuganathan and Earle, 1991).…”

QTL analyses of seed weight during the development of soybean (Glycine max L. Merr.)

“…Traditionally, plant improvement has relied on phenotypic selection of populations from crosses between cultivars and experimental lines (Stuber et al, 1992). Improvements in soybean seed weight by gene introgression has been slowed because phenotypic selection is complicated by significant genotype  environment interactions (GE) (Mansur et al, 1996;Mian et al, 1996). Consequently, selection for soybean cultivars with high and stable 100-seed weight requires evaluation in multiple environments over several years, which is expensive, time consuming and labor intensive.…”

“…Molecular markers offer a faster and more accurate approach to breeding for traits such as seed weight, as selection can be based on genotype rather than solely on phenotype (Mansur et al, 1996;Mian et al, 1996). The use of molecular markers for indirect selection of important agronomic traits, or marker-assisted selection (MAS) can improve the efficiency of traditional plant breeding (Allen, 1994).…”

“…In the past decade, several studies have focused on the mapping of quantitative trait loci (QTL) associated with soybean seed weight (Mansur et al, 1996;Mian, 1996;Hoeck et al, 2003;Zhang et al, 2004;Panthee et al, 2005). In most of these reports, the trait was only measured after harvest.…”