Yamauchi (2018) Genotypic variations in the plasticity of nodal root penetration through the hardpan during soil moisture fluctuations among four rice varieties,

Yamauchi (2018) Root plasticity under fluctuating soil moisture stress exhibited by backcross inbred line of a rice variety, Nipponbare carrying introgressed segments from KDML105 and detection of the associated QTLs,

Tomato is an important vegetable in Ghanaian diet and contributes enormously in livelihood improvement. Tomato production is threatened by a high prevalence of biotic and abiotic stresses as well as increased postharvest losses and poor agronomic practices, thereby resulting in massive importation of tomato and its products to meet the local demands. The recent introduction of greenhouse vegetable cultivation technology in Ghana is a sustainable attempt in addressing and ensuring year-round production of vegetables including tomato. However, research on agronomic practices targeted to improving yield and fruit quality under greenhouse conditions in Ghana is scarcely available. Therefore, this study seeks to evaluate the effect of plant spacing and topping on tomato yield and fruit quality under greenhouse conditions. A 3 ×3 factorial treatment arranged in a completely randomized design (CRD) with three replications was used. Two factors, plant spacing and topping with each having three levels, were used. Thus, the levels for plant spacing were 0.15 m × 1.3 m, 0.2 m × 1.3 m, and 0.3 m × 1.3 m while topping treatments at trusses 2, 3, and 4 (control) were done. The results showed that yield was significantly influenced by plant spacing in both experiments. The interaction effect of 0.2 m × 1.3 m plant spacing and topping at truss 2 showed significantly higher yields. Furthermore, juice volume was significantly increased by plant spacing. Again, 0.2 m × 1.3 m plant spacing by truss 2 topping interaction produced the highest juice volume. Therefore, these agronomic practices could be an essential and effective approach in achieving higher tomato production with improved fruit quality under greenhouse cultivation to ensure sustainable food security.

Soil moisture fluctuation (SMF) stress due to erratic rainfall in rainfed lowland (RFL) rice ecosystems negatively affect production. Under such condition, root plasticity is one of the key traits that play important roles for plant adaptation. This study aimed to evaluate root plasticity expression and its functional roles in water uptake, dry matter production and yield under SMF using three chromosome segment substitution lines (CSSLs) with major genetic background of KDML105 and a common substituted segment in chromosome 8. The CSSLs showed greater shoot dry matter production than KDML105 under SMF, which was attributed to the maintenance of stomatal conductance resulting in higher grain yield. The root system development based on total root length of the CSSLs were significantly higher than that of KDML105 due to the promoted production of nodal and lateral roots. These results implied that the common substituted segments in chromosome 8 of the 3 CSSLs may be responsible for the expression of their root plasticity under SMF and contributed to the increase in water uptake and consequently dry matter production and yield. These CSSLs could be used as a good source of genetic material for drought resistance breeding programs targeting rainfed lowland condition with fluctuating soil moisture environments and for further genetic studies to elucidate mechanisms underlying root plasticity. ARTICLE HISTORY

Greenhouse vegetable cultivation offers one of the optimistic approaches to ensuring sustainable food and nutrition security in the tropics. Although greenhouse vegetable production is known to be costly, this system of production is gaining popularity and contributes to sustainable tomato production with improved fruit quality and productivity, which results in higher economic returns. Among vegetable crops, tomato is the most cultivated under this system. A study was conducted to identify suitable soilless media for regenerating tomato cuttings from axillary stem of tomato plants and to assess the agronomic performance of the regenerated cuttings under greenhouse condition. The tomato cuttings were raised using 100% rice husk biochar, 100% rice husk, 100% cocopeat, 50% biochar +50% cocopeat, 50% cocopeat +50% rice husk. Two tomato hybrid varieties (Lebombo and Anna) were used. Cuttings from axillary stems were compared with those raised from seed. A 2 × 2 factorial experiment was arranged in a Completely Randomized Design (CRD) with four replications. From the study, 100% rice husk biochar was found to induce root development in stem cuttings of tomato. However, no significant differences in yield and fruit quality were found between plants raised from seed and those from stem cuttings.