Fine Mapping of the SCN Resistance QTL cqSCN‐006 and cqSCN‐007 from Glycine soja PI 468916

Abstract

ABSTRACTSoybean cyst nematode (SCN) (Heterodera glycines Ichinohe [HG]) is one of the most serious soybean pests [Glycine max (L.) Merr.] worldwide and resistance is controlled by quantitative trait loci (QTL). The fine mapping of new SCN resistance QTL can provide information useful for marker‐assisted selection (MAS) in breeding programs and tools for the eventual cloning of the QTL. The objective of this study was to fine map the SCN resistance QTL cqSCN‐006 and cqSCN‐007 that originated from Glycine soja Sieb. and Zucc. plant introduction (PI) 468916. The fine mapping was done by selecting plants with recombination near these genes and testing progeny of selected plants for resistance to the HG type 2.5.7 SCN isolate PA5 and with genetic markers. For cqSCN‐006, 1236 F5 plants and 1662 F6 plants were tested with simple sequence repeat (SSR) markers flanking the QTL, and the progeny from 20 recombinant plants were tested with genetic markers and for SCN resistance. This resulted in the mapping of cqSCN‐006 to a 803.4 kb interval on soybean chromosome (chr) 15. For cqSCN‐007, 1668 F5 plants were screened with flanking SSR markers, the progeny of 18 recombinant plants were tested, and cqQTL‐007 was mapped to a 146.5 kb interval on chr 18. The markers identified in this study will be useful to breeders developing SCN‐resistant cultivars and will be highly predictive for determining which plants carry the SCN resistance QTL alleles.