Putative Alleles for Increased Yield from Soybean Plant Introductions

cated that soybean PIs may have alleles for enhanced seed yield. Improving seed yield of soybean [Glycine max (L.) Merr.] is an Molecular marker analysis can aid in the discovery important breeding goal. The objective of this study was to evaluate and mapping of QTL associated with beneficial and two soybean PIs as sources of alleles for the enhancement of seed novel alleles from exotic parents. For example, in soyyield in North American cultivars. A population of 167 F5–derived lines was developed from a cross between ‘BSR 101’ and the experibean, two populations of recombinant inbred lines mental line LG82-8379. BSR 101 has nine of 10 major ancestral lines (RILs) derived from ‘Minsoy’ and ‘Archer’, and ‘Noir 1’ contributing to the commercial gene pool of North America, while and Archer (Orf et al., 1999) have been used extensively LG82-8379 was selected from a cross between PI 68508 and FC for the identification of QTL governing agronomic and 04007B. The F5–derived lines, divided into three sets based on matuseed composition traits utilizing molecular markers (Orf rity, were evaluated for 145 polymorphic simple sequence repeat et al., 1999; Terry et al., 2000; VanToai et al., 2001). In (SSR) marker loci and for seed yield and other agronomic traits in 12 one study comparing these two RIL populations, Orf environments. Fifteen quantitative trait loci (QTL) were significantly et al. (1999) identified QTL for plant height, lodging, [P 0.05, likelihood of odds (LOD) 2.5] associated with seed yield days to flowering and maturity, reproductive period, in at least one set with two significant across all sets. For nine of the seed yield, seed weight, and seed oil and protein concenyield QTL, the LG82-8379 alleles were associated with yield increases tration. At many of the QTL identified in this study, of 1.7 to 5.4% while the BSR 101 alleles increased yield 2.4 to 4.4% at six yield QTL. Four yield QTL were associated with significant the beneficial or novel alleles were those provided by changes in R8, eight with plant height, and three with seed protein Minsoy and Noir 1. Minsoy and Noir 1 are divergent concentration. Additional QTL were identified for R8, plant height, in lineage from each other and from North American lodging, and seed protein and oil concentration. These results indicate cultivars (Mansur et al., 1993a, 1993b; Orf et al., 1999), that soybean PIs have the genetic potential for improving seed yield whereas Archer is a North American cultivar (Cianzio of U.S. soybean cultivars. et al., 1991). Yield alleles from exotic sources are not well documented in soybean and those identified have often been I seed yield in soybean is an important goal related to other agronomic traits such as maturity. In of breeding programs. In North America, soybean this study, a soybean population consisting of F5–derived yield improvement comes mainly from selection in poplines was developed from a cross between ‘BSR 101’ ulations from crosses between commercial cultivars or and the experimental line LG82-8379. The pedigree of experimental lines derived from these cultivars. PediBSR 101 has nine of 10 ancestral lines that have made gree and genetic marker studies have shown that the the greatest contribution to the commercially used gene genetic base of the North American soybean gene pool pool of North America (Bernard et al., 1988; Gizlice et is narrow (Apuya et al., 1988; Keim et al., 1989; Gizlice al., 1994) whereas LG82-8379 was selected from a cross et al., 1993, 1994; Thompson et al., 1998). This narrow between two soybean PIs, PI 68508 and FC 04007B. genetic base has occurred primarily from using a small Using random amplified polymorphic DNA markers, number of ancestral lines as the founding stock (Gizlice the two PIs had been shown to be genetically distinct et al., 1993, 1994). from all major ancestral lines of modern North AmeriIntrogressing exotic germplasm into cultivars to incan soybean cultivars (Thompson et al., 1998). From crease genetic diversity within domesticated crops has this cross, high-yielding and genetically diverse experibeen used to enhance complex traits such as yield (Tanksmental lines have been developed (Thompson and Nelley and McCouch, 1997). In soybean, Thompson and son, 1998) and released (Thompson et al., 1999). The Nelson (1998) tested experimental lines derived from objective of this study was to evaluate the two PIs as crossing North American cultivars with several plant sources of alleles for the enhancement of seed yield in introductions. Lines that yielded significantly more than North American cultivars. their North American parent were identified which indiMATERIALS AND METHODS A soybean population consisting of 167 indeterminate F5– E.A. Kabelka and B.W. Diers, Dep. of Crop Sci., I.C. Baianu and T. derived lines was developed by single seed descent from a You, Dep. of Food Sci. and Human Nutrition, and D.J. Neece and cross between BSR 101, a maturity group (MG) II cultivar, R.L. Nelson, USDA-ARS, Soybean/Maize Germplasm, Pathology, and Genetics Research Unit, Dep. of Crop Sci., Univ. of Illinois, and the MG IV experimental line LG82-8379. LG82-8379 was Urbana, IL 61801; W.R. Fehr, Dep. of Agronomy, Iowa State Univ., derived from a cross between two soybean PIs, PI 68508 and Ames, IA 50011; A.R. LeRoy, Dep. of Agronomy, Purdue Univ., FC 04007B. Each line descended from a different F2 seed West LaFayette, IN 47907. Received 13 Dec. 2002. *Corresponding author ([email protected]). Abbreviations: LOD, likelihood of odds; MG, maturity group; PCR, polymerase chain reaction; QTL, quantitative trait locus/loci; R1, days Published in Crop Sci. 44:784–791 (2004).  Crop Science Society of America to flower; R8, days to maturity; RIL, recombinant inbred line; SSR, simple sequence repeat. 677 S. Segoe Rd., Madison, WI 53711 USA