Location: Plant Genetic Resources Research
Project Number: 8060-21000-024-06-A
Project Type: General Cooperative Agreement
Start Date: Aug 30, 2013
End Date: Aug 29, 2014
The objective of this project is to characterize and regenerate a population of recombinant inbred lines (RILs) in tomato for certain traits which are important for their maintenance and utilization for breeding and research purposes. The RILs were synthesized by Majid Foolad’s group at Penn State Univ. from a cross between S. lycopersicum cv. NC EBR-1 and S. pimpinellifolium LA2093, followed by multiple generations of single seed descent from the F2. NC EBR-1 is an early blight resistant breeding line developed by Randy Gardner at North Carolina State Univ. LA2093 is an accession of S. pimpinellifolium collected at La Union, Ecuador by Charlie Rick. This project will focus on evaluating 148 lines (out of 170) currently at the F8 generation.
The TGRC will grow the RIL population in the field this summer for observation and seed multiplication. Observations will be made to determine the risk of outcrossing. Seed multiplication will be accomplished by allowing plants to self-pollinate in the field (i.e. open pollination). In addition, 1-2 inflorescences per RIL will be bagged to exclude pollinators, and extract seed from these fruit separately from the OP’s. Seed from bagged inflorescences will be used as starting material for future seed regenerations. OP seed will be used to fill seed requests. The RILs will also be phenotyped for any unambiguous monogenic characters that are segregating in this population. The genotypes of each RIL for the informative monogenic marker loci will provide baseline information for detecting outcrossing events or mix-ups in the future. In addition, by combining the visual marker genotypes with the high density GBS data, it should be possible to obtain relatively precise genetic and physical map locations for the underlying genes. Digital images of each RIL will be taken to record their phenotypes. These images could be useful to breeders and researchers for selecting lines with specific traits (e.g. fruit color, size or shape). For the TGRC, they will provide another tool for distinguishing individual lines and maintaining line purity over successive generations of seed multiplication. We will take images of leaves, stems, flowers, inflorescences, and fruit (whole and cross-section). The choice of plant materials and layout of the images will be adjusted, as needed, to capture the phenotypic variation and salient morphological features that are evident in the RIL population when it is grown. The evaluation data and images for the RILs, plus the parents, will be incorporated into the TGRC database records on these accessions.