Phenotypic plasticity of drought tolerance in tomato (Solanum lycopersicum L.) landraces and hybrid cultivars in Benin, Africa

Authors: EZIN, VINCENT - Universite` D` Abomey-Calavi; HOUESSOU, FELIX - Universite` D` Abomey-Calavi; Bryla, David; AHANCHEDE, ADAM - Universite` D` Abomey-Calavi

Submitted to: Journal of Food Agriculture and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2019
Publication Date: 11/14/2019
Citation: Ezin, V., Houessou, F., Bryla, D.R., Ahanchede, A. 2019. Phenotypic plasticity of drought tolerance in tomato (Solanum lycopersicum L.) landraces and hybrid cultivars in Benin, Africa. Journal of Food Agriculture and Environment. 17(3/4):45-53. https://doi.org/10.1234/4.2019.5565.
DOI: https://doi.org/10.1234/4.2019.5565

Interpretive Summary: Tomato ranks first amongst vegetables produced in Benin and is worth a considerable amount of money to the national economy. However, yields of tomato in western Africa, particularly in Benin, have not been encouraging, especially when compared to production in developed countries. For example, yield per hectare in Benin was estimated to be only 14.3% of that produced in the United States. Furthermore, the price of tomatoes in Benin has increased in recent years due to the fact that there is less rain and prolonged dry seasons. The objective of this study was to screen existing tomato genotypes from Benin for resistance to drought during both vegetative and reproductive stages of development and identify those that are most tolerant. Two local landraces, Diho and Toviklin, tolerated drought better than most other genotypes tested, including F1 Mongal, which is considered a good cultivar for production in the tropics. These landraces could potentially be used in breeding programs to improve drought and perhaps heat tolerance in tomato and are recommended to farmers as potential candidate to be sown during the dry season. Three hybrids, Petomech, Rodeo, and Tropimech, were also tolerant drought.

Technical Abstract: The aim of the present study was to evaluate drought tolerance and its relation to vegetative, reproductive, and physiological characteristics of 20 tomato genotypes, including 14 local landraces, five hybrid cultivars, and a wild relative species (LA1579). The experiment was carried out at the International Institute of Tropical Agriculture in Benin, Africa. Each genotype was exposed to three treatments, including a fully irrigated control, moderate drought (no water for 15 days during the vegetative stage and 7 days during the reproductive stage), and severe drought (no water for 21 days during the vegetative stage and 9 days during the reproductive stage). Plant height and leaf production was reduced by the initial episode of severe drought but was unaffected in most genotypes by moderate drought. There was also no difference in leaf chlorophyll levels as a result of drought, but drought had a significant effect on leaf fluorescence in many genotypes. The landraces flowered earlier and more profusely than the hybrids but as a group both were equally affected by drought during flowering and fruit development. Some genotypes were also affected by heat, including LA1579, which aborted its flowers and produced no fruit in any treatment. Principle component analysis based on a phenotypic drought tolerance index clearly distinguished tomato genotypes into four drought tolerance clusters. Overall, two local landraces, Diho and Tovinklin, were most tolerant to drought amongst the genotypes and potentially could be used in breeding programs to improve drought tolerance in tomato.