Callus Induction and Plant Regeneration from Dehusked Mature Seeds of Three Accessions of African Rice (Oryza glaberrima Steud.)

Three accessions of African rice (Oryza glaberrima Steud.), Guame, N/4 and SARI 1 were assessed for their callus induction and plant regeneration ability from mature dehusked seeds on Murashige and Skoog (MS), (1962) basal medium supplemented with varying concentrations of plant growth regulators. Mature dehusked seeds were inoculated onto callus induction medium consisting of MS supplemented with varying concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) in the range 0.0-6.0mg/l. All tested accessions exhibited highest callus induction at 4.0 mg/l 2,4-D. Callus induction frequency was significantly (p≤0.05) different among the accessions, as well as among the 2,4-D levels  tested. Calli obtained were also sub-cultured on MS medium, further supplemented with varying concentrations (0.0-2.5 mg/l) of 6-benzylaminopurine (BAP). The highest regeneration frequency was obtained on medium containing 2.0 mg/1 BAP.  However, callus induced on 3.0 mg/l 2,4-D and further sub-cultured on  2.0 mg/l BAP gave the best response in terms of shoot proliferation, shoot growth and root development; therefore, considered to be the optimum concentrations for callus induction and plant regeneration respectively. Plantlet regeneration was achieved only in the accession N/4 while Guame and SARI 1 exhibited poor regeneration response. Among the three African rice accessions evaluated, N/4 was the most promising in terms of callus induction frequency and regeneration ability. Keywords: Oryza glaberrima, callus induction, plantlet regeneration, shoot proliferation, 2, 4-dichlorophenoxyacetic acid, 6-benzylaminopurine

Spread of African cassava mosaic virus from cassava (Manihot esculenta Crantz) to physic nut (Jatropha curcas L.) in Ghana

Investigations were made on the susceptibility of physic nut (Jatropha curcas L.) to African cassava mosaic virus (ACMV) and its possible role as an alternative host of the virus in Ghana. Ten J. curcas accessions in a field trial were interplanted with ACMV-infected cassava (Manihot esculenta Crantz) and left to natural spread of the virus from the cassava to the J. curcas plants for a period of 12 months. Populations of the whitefly vector, Bemisia tabaci (Gennadius) and the incidence of African cassava mosaic disease (ACMD) were monitored during the period. The J. curcas plants had low whitefly numbers, both in the wet (September – October, 2008) season and in the dry (January – February, 2009) season. By the end of the experimental period, 37.7% of the 120 J. curcas plants tested in all the accessions were found to be infected by ACMV, as assessed by symptom expression, double antibody-sandwich (DAS) ELISA or sap inoculation to Nicotiana benthamiana indicator plants. There were wide variations within and between the J. curcas accessions in their response to ACMV infection. This work is the first report of the natural infection of J. curcas by ACMV

Limited effects of shade on physiological performances of cocoa (Theobroma cacao L.) under elevated temperature

Open Access Article; Published online: 08 Jul 2022Shade is one of the recommended management solutions to mitigate the effects of heat stress, which is a major challenge for cocoa production globally. Nevertheless, there are limited studies to verify this hypothesis. Here, we evaluate the effects of heat and shade on cocoa physiology using experimental plots with six-month old potted seedlings in a randomized complete block design. Infrared heaters were applied for one month to increase leaf temperatures by an average of 5–7 ºC (heat treatment) compared with no heat (unheated treatments), and shaded plants were placed under a shade net removing 60% of the light compared with no shade (sun treatments). Plants under heat treatments in sun and in shade showed severe reduction in photosynthesis. Measurements of chlorophyll fluorescence and photosynthetic light response curves indicated that heat caused damages at photosystem II and additionally resulted in lower rates of maximal photosynthesis. Temperature optima for photosynthesis were at 31–33 ºC with only small differences between treatments, and as light saturation was reached at low PAR levels of 325 – 380 µmol m−2 s−1 in shade and 427 – 521 µmol m−2 s−1 in sun, ambient rates of photosynthesis were comparable between sun and shade treatments. Heat treatments resulted in decreased concentrations of chlorophyll and changed pigment composition, reduced specific leaf areas, and plant biomass. While shade may benefit cocoa seedlings, our results indicate that the positive effects may not be sufficient to counteract the negative effects of increased temperatures on cocoa physiology

Combined effects of shade and drought on physiology, growth, and yield of mature cocoa trees

Open Access ArticleClimate models predict decreasing precipitation and increasing air temperature, causing concern for the future of cocoa in the major producing regions worldwide. It has been suggested that shade could alleviate stress by reducing radiation intensity and conserving soil moisture, but few on-farm cocoa studies are testing this hypothesis. Here, for 33 months, we subjected twelve-year cocoa plants in Ghana to three levels of rainwater suppression (full rainwater, 1/3 rainwater suppression and 2/3 rainwater suppression) under full sun or 40 % uniform shade in a split plot design, monitoring soil moisture, physiological parameters, growth, and yield. Volumetric soil moisture (ϴw) contents in the treatments ranged between 0.20 and 0.45 m3m−3 and increased under shade. Rainwater suppression decreased leaf water potentials (ѱw), reaching −1.5 MPa in full sun conditions indicating severe drought. Stomatal conductance (gs) was decreased under the full sun but was not affected by rainwater suppression, illustrating the limited control of water loss in cocoa plants. Although pre-dawn chlorophyll fluorescence (Fv/Fm) indicated photoinhibition, rates of photosynthesis (Pn) were highest in full sun. On the other hand, litter fall was highest in the full sun and under water stress, while diameter growth and carbon accumulation increased in the shade but was negatively affected by rainwater suppression. Abortion of fruits and damage to pods were high under shade, but dry bean yield was higher compared to under the full sun. The absence of interactions between shade treatments and rainwater suppression suggests that shade may improve the performance of cocoa, but not sufficiently to counteract the negative effects of water stress under field conditions

Cultivation and use of African yam bean (Sphenostylis stenocarpa) in the Volta Region of Ghana

The African yam bean (Sphenostylis stenocarpa Hochst ex A. Rich) is a legumi nous crop found in the Volta Region of Ghana. Three expeditions were under taken in the region between September 1998 and March 1999 to investigate the extent of cultivation and use of the bean as the basis for research into its develop ment and promotion as a major crop. Its cultivation is currently localized around Nkwanta and Ho West Districts. It is grown as a minor crop in mixed associa tion with yam and cassava. It is used extensively in various dietary prepara tions and has potential for supplement ing the protein requirements of many families throughout the year. Its current low status as a minor crop means that this potential is largely unexploited. Re search efforts are required to improve its agronomic characteristics and promote its cultivation and use as a major crop. The Journal of Food Technology in Africa Volume 6 No.3, 2001, pp. 74-77 KEY WORDS: African yam bean, food security, Ghana, legume, pulse, Sphenostylis stenocarpa, under-exploited cro

Cultivation and use of African yam bean (Sphenostylis stenocarpa) in the Volta Region of Ghana

The African yam bean (Sphenostylis stenocarpa Hochst ex A. Rich) is a leguminous crop found in the Volta Region of Ghana. Three expeditions were undertaken in the region between September 1998 and March 1999 to investigate the extent of cultivation and use of the bean as the basis for research into its development and promotion as a major crop. Its cultivation is currently localized around Nkwanta and Ho West Districts. It is grown as a minor crop in mixed association with yam and cassava. It is used extensively in various dietary preparations and has potential for supplementing the protein requirements of many families throughout the year. Its current low status as a minor crop means that this potential is largely unexploited. Research efforts are required to improve its agronomic characteristics and promote its cultivation and use as a major crop

H2SO4-modified Aloe vera leaf shells for the removal of P-chlorophenol and methylene blue from aqueous environment

In this study, the surface properties of activated carbon from Aloe vera leaf shells were modified by sulfuric acid Aloe vera-acid activated carbon (AV-AAC) and then used as a novel adsorbent to remove para-chlorophenol (p-CP) and methylene blue (MB) from aqueous solutions. The adsorbent was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and Fourier transform infrared spectra (FTIR). The maximum monolayer adsorption capacities were found to be 137 and 192.3 mg/g for p-CP and MB, respectively. Due to low-cost and high adsorption capacity, AV-AAC can be considered as an effective adsorbent for wastewater treatment containing p-CP or MB

H2SO4-modified Aloe vera leaf shells for the removal of P-chlorophenol and methylene blue from aqueous environment

In this study, the surface properties of activated carbon from Aloe vera leaf shells were modified by sulfuric acid Aloe vera-acid activated carbon (AV-AAC) and then used as a novel adsorbent to remove para-chlorophenol (p-CP) and methylene blue (MB) from aqueous solutions. The adsorbent was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and Fourier transform infrared spectra (FTIR). The maximum monolayer adsorption capacities were found to be 137 and 192.3 mg/g for p-CP and MB, respectively. Due to low-cost and high adsorption capacity, AV-AAC can be considered as an effective adsorbent for wastewater treatment containing p-CP or MB. © 2018 Informa UK Limited, trading as Taylor & Francis Grou