Drought is one of the abiotic stresses with more effect on crop productivity world-wide. Understanding plants’ response to drought is fundamental to produce drought tolerant varieties. Marker-assisted selection (MAS) helps reduce the time needed to breed new varieties by using markers associated with the trait being introduced. The work presented in this thesis is a first step in the identification of the molecular markers associated to drought response and recovery in white clover (Trifolium repens). The LemnaTec high-throughput phenotyping system was used to develop a total of 12 indexes that allowed us to phenotype the response to drought of the Stolon Mapping Population (SoMP). An integrated linkage map of the parents of the SoMP family was constructed from SNPs. The integrated map generated has 312 markers over 3211.283 cM on 14 linkage groups (LGs). The analysis of QTL was performed using both linkage analysis and association analysis. By linkage analysis several clustered QTLs were found on LG 8b suggesting this LG is a hotspot for drought response/recovery on white clover, especially in the control of greenness/yellowness. Both the indexes developed, and the integrated linkage map created during this thesis will help in the advancement of the knowledge and understanding of the molecular mechanisms of the drought response in white clover, helping in future QTL linkage analysis and MAS of drought tolerant white clover varieties.
|Adriana Ravagnani (Goruchwylydd) & John Doonan (Goruchwylydd)