Mapping QTL Conditioning Leaf Traits of Soybean in a Recombinant Inbred Line Population.

Leaflet shape in soybean [Glycine max (L.) Merr] has been reported to be linked with the number of seeds per pod. The narrow leaflet plants tend to produce a greater number of seeds, but smaller seeds than broad leaflet plants. High specific leaf weight (SLW) in soybean may increase photosynthetic rate per unit leaf area and drought tolerance. Generally, the SLW shows negative correlation with leaf size. The objective of the present study was to identify quantitative trait loci (QTL) associated with leaflet shape, leaf area, and SLW in soybean. A total of 94 F₇-derived recombinant inbred lines from a cross of ‘Wyandot’ and PI 567301B and 516 single nucleotide polymorphism (SNP) markers were used to construct a genetic linkage map. Data for leaf traits were collected from plants grown in the field during 2011 in two replicates. For three leaf traits, a total of nineteen QTL were detected from single-factor ANOVA at the 0.01 significance level. Six QTL for leaflet shape explaining 9.1-27.5% of phenotypic variation, nine QTL for leaf area accounting for 7.3-18.8% of phenotypic variation and four QTL for SLW explaining 7.1-9.5 of phenotypic variation were identified. Of these, 1, 5, and 4 QTL for leaflet shape, leaf area, and SLW, respectively have not been detected in any previous study (Soybase; www.soybase.org/). Second year phenotypic data will be collected from the field in 2012 and results across years will also be presented.