Abstract:

Formation of new Universitary postgraduates specialized in developing new varieties of crops of economic interest is of great relevance for addressing the challenges associated to climate change. To achieve this goal, it is necessary to acquire skills for performing interspecific crosses between cultivated species and their relatives. Crop wild relatives (CWRs) often grow in hostile environments (e.g. desertic or salinized areas) and have developed very efficient mechanisms to overcome the environmental stresses. Unfortunately, due to the pre- and post-zygotic barriers sexual crosses between CWRs and cultivated species are often difficult. A valuable strategy to overcome abortions because the post-zygotic barrier is the extraction of the embryos from the seeds to allow their development in an in vitro culture medium. This technique, called embryo rescue, required specialized hands-on training to be successfully performed. Our Institute offers a master's degree in plant breeding, in which plant hybridization is a pillar key of many subjects. To address the plant incompatibility, the course on "In vitro culture" (5 ECTS) provides to the students the essential techniques needed in breeding programs when sexual barriers exist. In order to improve the abilities of students for distant hybridization between a crop and wild relatives, we have devised a practical session on in vitro embryo rescue from mature and immature seeds using eggplant as a model crop. Common eggplant (Solanum melongena) has many wild related species from different genepools with a broad potential for its genetic improvement for tolerance and resistance to abiotic and biotic stresses. However, on occasion embryo degeneration after successful pollination prevents obtaining hybrid plants.

This session requires 9 hours divided into three blocks involving:
i) the necessary means for the growth of rescued embryos,
ii) performing crosses between crops and wild species, and
iii) the rescue of the embryos from seeds resulting from these crosses.

Furthermore, this practical session allows students to acquire the hands-on techniques necessary for in vitro culture (work in sterile conditions, preparation of the media culture, and disinfection of materials) essential for the development of new varieties using CWRs as donor parents, where embryo rescue is needed. This practical session can also be applied to other Master studies in the field of Plant Sciences and Genetics.

Keywords:

Embryo rescue, plant breeding, crop wild relatives, eggplant, crosses.