ABSTRACT
Selection of advanced tomato lines with different calcium concentrations in response to Alternaria lycopersici infection

Alba Melissa Castañeda-Villa1, Ricardo Lobato-Ortiz1*, Hilda Victoria Silva-Rojas1, J. Jesús García-Zavala1, Humberto Vaquera-Huerta1, Guillermo Calderón-Zavala1, Aurelio Hernández-Bautista1, Alexander López-Hernández1, Dania Samantha Castañeda-Villa2, and Martha Hernández-Rodríguez1
 
Several adverse biotic and abiotic factors occur during the development of tomato (Solanum lycopersicum L.), reducing yield and fruit quality. This study evaluated the Alternaria foliar severity and subsequently the tolerance to Ca deficiency in 90 tomato (Solanum lycopersicum L.) genotypes, including 89 advanced S4 lines and one commercial control. The influence of Alternaria on yield and its components as average fruit weight, and total number of fruits per plant was studied using a randomized complete block design with three replicates and four plants per replicate. After plant pathology analysis, Alternaria lycopersici was identified as the pathogen responsible for Ca deficiency and yield loss. Despite of the pressure of A. lycopersici and Ca deficiency, 14 advanced lines showed a yield like that exhibited by the commercial check ‘El Cid’. Among 89 S4 lines, five tomato lines were resistant to A. lycopersici infection (± 0% leaf severity), while 52 lines showed moderate resistance (≤ 25% leaf severity). A total of 24 advanced lines with no symptoms of blossom end rot due to Ca deficiency were identified. Additionally, two outstanding genotypes (48 and 49) from the source LOR95´C were selected for their high total fruit weight per plant and natural resistance to A. lycopersici. These lines showed no Ca deficiency, so they can be used as open-pollination varieties to improve the program’s elite materials. Finally, susceptible lines to A. lycopersici showed Ca absorption capacity decreases in fruit (26.15 µg g-1) and individual fruit weight (59.91 g). In contrast, resistant lines had values of 162.33 µg g-1, and an individual fruit weight of 107.11 g. This suggests that the lower the resistance to A. lycopersici in advanced lines, the more fruits with blossom end rot and lower average fruit weight due to calcium deficiency in the plant.
Keywords: Blossom end rot, genetic diversity, physiopathology, resistance, Solanum lycopersicum.
1Colegio de Postgraduados, Campus Montecillo, Montecillo, Texcoco, Estado de México, CP 56264, México.
2Universidad Autónoma Agraria Antonio Narro, Saltillo, Coahuila, CP 25315, México.