Tomato yellow leaf curl virus (TYLCV) is a major constraint to tomato production in Spain. This virus was observed for the first time in several tomato fields in Murcia (Spain) in the autumn of 1992 and Canary Islands in 1999. Currently the virus is prevalent along the Mediterranean coast of Spain (provinces of Málaga, Granada, Almería, Murcia, Alicante, Valencia, and Barcelona) and in the Canary Islands. Two viral species have been identified in Spain, TYLCV-Sar in 1992 and TYLCV-Is in 1997. TYLCV-Is is more severe than TYLCV-Sar and produces the greatest economic losses. Curling of leaflets, yellowing, and growth reduction are more pronounced in plants infected with TYLCV-Is than in those infected with TYLCV-Sar. In order to study the presence and behavior of both viral species in the affected area, over 1,320 tomato plants were sampled. DNA was extracted from the samples and analyzed by polymerase chain reaction (PCR) amplification. The degenerate primer pair for Begomovirus detection (AV494/AC1048) (2) was used to amplify the core region of the capsid protein gene. The amplified fragments were later analysed by restriction fragment length polymorphism (RFLP) with HaeIII enzyme to differentiate between TYLCV-Is and TYLCV-Sar species. The results showed that TYLCV-Sar (43.4%) and TYLCV-Is (56.6%) coexist in tomato crops and, in contrast with previous results (1), displacement of TYLCV-Sar for TYLCV-Is was observed. A search for the alternative hosts that may serve as virus reservoirs in areas where the virus is prevalent involved testing 210 samples of 95 species of weeds by PCR, with the same primers. The following species were found to be infected: Conyza sumatrensis (Retz.) E. Walker, Convolvulus sp., Cuscuta sp., Chenopodium murale L., Datura stramonium L., Dittrichia viscosa (L.) W. Greuter, Malva parviflora L., and Solanum nigrum L. This is the first reference of C. sumatrensis, Convolvulus sp., Cuscuta sp., and Ch. murale as natural hosts of TYLCV. These plants were symptomless. References: (1) S. Sanchez-Campos et al. Phytopathology 89:1038, 1999. (2) S. D. Wyatt et al. Phytopathology 86:1288, 1996.

Notwithstanding the importance of eggplant in global horticulture, doubled haploid production in this species is still far from being efficient. Although acknowledged to have a role in the efficiency of androgenesis induction, factors such as the growth conditions of donor plant or the in vitro culture environment have not been deeply explored or not explored at all in eggplant, which leaves room for further improvement. In this work, we investigated the effects of different in vivo and in vitro parameters on the androgenic performance of different eggplant genotypes, including two hybrids and a DH line. The in vivo parameters included the exposure of donor plants to different temperature and light conditions and to increased levels of boron. The in vitro parameters included the use of different concentrations of NLN medium components, sucrose and growth regulators, and the suspension of microspores at different densities. Our results showed that whereas greenhouse temperature variations or boron application did not to have a positive influence, greenhouse lighting influenced their viability, thereby conditioning the embryogenic response. Changes in different sucrose, salts and hormone levels had different effects in the genotypes studied, which correlated with their genetic constitution. Finally, we determined the best microspore density, different from that previously proposed. Our work shed light on the role of different factors involved in eggplant microspore cultures, some of them not yet studied, contributing to make microspore culture a more efficient tool in eggplant breeding.

Por último quiero dedicarle el resultado de este trabajo a mi hermano. Tú eres la persona más importante para mí y por la que he sacado fuerzas cada vez que me he desanimado a lo largo de estos años. Nunca me arrepentiré de las decisiones que me han llevado a llegar hasta aquí. Lo único que siempre he sentido es que este camino ha hecho que no haya podido compartir contigo tantos momentos como me hubiera gustado. Espero de verdad que eso cambie con nuestros nuevos planes. Te quiero.