Hybrid performance of bottle gourd [Lagenaria siceraria] under drought stress and non-stress conditions

Abstract

Bottle gourd (Lagenaria siceraria (Molina) Standl.) genetic resources cultivated in sub-Saharan Africa (SSA) are relatively tolerant to heat and drought stress, presenting opportunities for developing climate-smart and drought-resilient cultivars adapted to dry environments. Therefore, the objective of this study was to determine drought tolerance and stability among newly-developed F₁ bottle gourd hybrids to recommend best-performers for production and commercialization in South Africa. Fifty-three F₁ families were developed and field evaluated with 12 parental accessions under non-stressed (NS) and drought-stressed (DS) conditions in two growing seasons using a 5 × 13 α-lattice design with three replicates. Data were collected on fruit yield per plant (FYPP) and drought tolerance indices computed. Genotype-by-environment interaction (GEI) patterns were inferred using the additive main effects and multiplicative interaction (AMMI) and genotype and genotype-by-environment (GGE) biplot analyses. Significant interactions were detected among test genotypes and water regimes for FYPP. The mean FYPP were 0.3 and 1.0 kg under DS and NS conditions. Based on the AMMI analysis, the proportions of the genotypic (G), environment (E) and GEI effects were computed at 6.49, 23.04 and 22.24 %, respectively. The GGE-biplot analysis explained 76.51 % of the total variation for FYPP. Based on tolerance indices, AMMI and GGE-biplot analyses the following hybrids were identified as drought tolerant and stable: BG-31 × BG-67, BG-27 × BG-31, BG-31 × BG-70, BG-31 × BG-78, BG-67 × BG-70, BG-58 × BG-79 and BG-58 × BG-80. The newly-developed bottle gourd hybris are recommended for cultivation in drought-prone agro-ecologies in South Africa and similar environments in SSA after multi-environment testing.