Essential oil yield and yield components of basil (Ocimum basilicum L.) as affected by genotype and intrarow spacing at Jimma, SW Ethiopia

Abstract

Basil is an aromatic, medicinal, culinary, and multifunctional herb which is grown in different parts of Ethiopia. Although the oil distilled from the herb, as well as its herbal yields, are a crucial input in the pharmaceutical industry and for culinary purposes, the yield obtained is below its potential due to various challenges. Genotype and plant spacing are two of the factors which contribute to the low production of the crop. A field trial was conducted at Jimma University College of Agriculture and Veterinary Medicine (JUCAVM) in 2016 and 2017 to assess the effect of genotype and plant spacing on essential oil yield and other yield-related traits of this important herb. Four promising genotypes (BO-1, BO-3, BO-4, and BO-5) and three plant spacings (20, 30, and 40 cm) were studied in a 4 × 3 factorial design arranged as randomized complete blocks (RCBD) with three replications. Data on plant height, leaf area, number of primary branches, essential oil content and oil yield were collected and analyzed. The analysis of variance revealed that there were highly significant (<em>p</em> < 0.01) interaction effect of genotype with plant spacing for all parameters tested. The maximum essential oil yield (7.88 kg ha<sup>−1</sup>) was obtained from genotype BO-5 at 30 cm spacing, whilst the least (2.68 kg ha<sup>−1</sup>) was recorded from BO-1 at 40 cm spacing. The maximum oil content (101 mL g<sup>−1</sup>) was gained from BO-1 at 20 cm, but BO-3 at 30 cm spacing recorded the least oil content though there were no significant differences between the three treatment combinations. Further studies at different locations and seasons will be important to for future local recommendations.

Agro‐morphological and phenotypic variability of sweet basil genotypes for breeding purposes

“…(2017) reported that variability of combined analysis results on quantitative traits of Ethiopian sweet basil genotypes showed wide range in number of primary branches per plant (6.08–8.98), number of internodes per main stem (4.68–6.80), and plant height (24.43–42.24 cm). Likewise, Alemu, Garedew, and Gebre (2018) indicated that plant height was significantly affected by genotype and plant spacing, and they also reported that plant height changed from 52 to 32 cm. Similarly, the plant height of different basil genotypes was found to be 20–60 cm (Annamaria, Bianca, Daniela, Simona, & Mirela, 2014), 22.9–57.0 cm (Telci et al., 2006), 40.0–76.9 cm (Erşahin, 2006), 60.89 cm (Golcz, Seidler Lozykowska, & Markiewicz, 2002), 65–88 cm (Nassar, El‐Segai, & Mohamed, 2013), 69.7–89.5 cm (Nurzyńska‐Wierdak, Rozek, & Borowski, 2011), 37.9–98.7 cm (Yaldiz, Çamlıca, Eratalar, & Kulak, 2017; Yaldiz, Gul, & Kulak, 2015), 59.28–62.5 cm (Dzida, 2010), 35.40–73.07 cm (Yaldız, Çamlıca, Özen, & Eratalar, 2019), 24.43–42.24 cm (Egata et al., 2017), 17.16–45.33 cm (Karaca, Kara, & Özcan, 2017), and 74–80 cm (Hewidy, Sultan, Elsayed, & Abdrabbo, 2014) under different ecological conditions.…”

Biomass production and essential oil content and composition in basil hydroponic systems using treated domestic effluents

“…This type of behavior has been observed in other studies under field conditions, such as Daneshian et al (2011), who studied two basil genotypes under three plant densities. Alemu et al (2018) reported the highest mean oil content for genotype 'BO-1' at the smallest spacing between plants (0.20 m), whereas two other genotypes ('BO-4' and 'BO-5') with various plant spacings (0.20, 0.30 and 0.40 m) did not influence the oil content, and, in general, the mean oil content did not exceed 1%.…”

Is there any relationship between agronomic traits, soil properties and essential oil profile of peppermint (Mentha piperita L.) treated by fertiliser treatments and irrigation regimes?

“…It has been argued that essential oil produced in young leaves is affected by photoperiodic modulation of monoterpene synthesis pathway (Nguyen & Saleh, 2019) because of the involvement of phytochrome in the process of essential oil synthesis. Also, change in LAI, related to sunlight quality, has the greatest impact on oil manufacturing from exogenous primary precursors (Alemu, Garedew, & Gebre, 2018).…”