Identification of causal relationships among traits related to drought resistance in Stylosanthes scabra using QTL analysis

• DOI: 10.1093/jexbot/52.355.203
• Publication Date: 2002-07-26T22:50:44Z
• Authors: Bala R. Thumma; Bodapati P. Naidu; Amaresh Chandra; Don F. Cameron; Len M. Bahnisch; Chunji Liu
• Keywords: Genetic linkage

Previous studies have shown that a negative relationship exists between transpiration efficiency (TE) and carbon isotope discrimination (Delta) TE specific leaf area (SLA) in Stylosanthes scabra. A glasshouse experiment was conducted to confirm these relationships an F(2) population study the causal nature of through quantitative trait loci (QTL) analysis. One hundred twenty genotypes from cross two within S. scabra were used. Three replications for each genotype maintained vegetative propagation. Water stress imposed by maintaining plants at 40% field capacity about 45 d. To facilitate QTL analysis, genetic linkage map consisting 151 RAPD markers developed. Results this show Delta significantly negatively correlated with biomass production. Similarly, SLA showed significant correlation Most present on groups 5 11. SLA, productivity traits clustered 13 24. unlinked marker also associated traits. There several coincident different At all QTL, direction effects consistent phenotypic data. Delta, high alleles low Delta. transpiration. trans-4-hydroxy-N:-methyl proline (MHP) relative water content (RWC), MHP RWC. This suggests Phenotypic data more closely production than TE. shows cause-effect may exist