The genetic basis of salad leaf processability

In order to improve salad leaves and increase shelf life, it is necessary to determine the genetic basis of leaf processability traits, which are related to leaf characteristics and development. The quantitative genetic approach used in this study is a multi-gene approach to improve the leaf quality with longer shelf life. The recombinant inbred lines (RILs) mapping population (F9/F10) used in this study was derived from a cross between cultivated lettuce (Lactuca sativa cv. Salinas) and wild lettuce (L. serriola acc. UC96US23). Significant correlations were found between shelf life and leaf area, weight, chlorophyll content, stomatal index and cell number. For the first time, the link was found between pre-harvest leaf growth characteristics and post-harvest shelf life, for an important leafy crop, lettuce. A total of 51 quantitative trait loci 9QTL) for the traits of interest were identified in this study, while 13 QTL were common in both field trials (Portugal and the UK) and they were proposed to be environment independent QTL. LG1: 90cM-100 cM and LG2: 80 cM-90 cM were ‘hot –spot’ areas, as several QTL co-located in these two regions. QTL for leaf processability and leaf development traits were co-located at LG1: 90 cM-100 cM. the candidate-gene strategy using single nucleotide polymorphisms (SNP) detection was explored for identification of candidate genes for leaf processability. The superior long-life line 112 and line 1 were selected for further commercial potential application. The identification of QTL and candidate genes for leaf development and processability will allow improvement of salad leaf quality through commercial breeding.