QTL Mapping of Panicle Architecture and Yield-related Traits Between Two U.S. Rice Cultivars ‘LaGrue’ and ‘Lemont’
Abstract Grain yield is a quantitative trait that is determined by several agronomic traits. Unfortunately, there is little information about the genetics behind yield components in U.S. rice cultivars. The objective of the study were to 1) conduct a QTL study for identification of chromosome regions associated with yield traits in two US developed rice cultivars and 2) identify candidate genes in major QTL regions related to yield traits. Four rice cultivars were evaluated in the summer 2017 at the University of Arkansas System Division of Agriculture’s Rice Research and Extension Center (RREC) at Stuttgart, AR for 15 agronomic traits associated with yield. Of the four cultivars, “LaGrue” had a higher number of seeds/panicle, number of primary panicle branches/panicle, and number of seeds/plant and “Lemont”, despite having longer panicles and higher 100 seed weight/panicle, produced the least number of seeds among the cultivars. A bi-parental population was developed from a cross between LaGrue and Lemont for QTL analysis. Leaf samples from F2 plants were collected for genetic analysis. A set of 322 F2:3 lines were evaluated in a randomized complete block design (RCBD) for several agronomic traits at two locations with three replications for each line. A total of 17 major QTLs were detected including two major QTLs for plant height on chromosome 1 and two major QTLs for flag leaf length and panicle length on chromosome 8 with seven candidate genes found in these regions. The results from the study would be useful for marker assisted selection in rice breeding.