In vitro regeneration and morphogenesis in Phyllanthus niruri L., an anti-plasmodial herb

We investigated the use of in vitro techniques for regeneration of adventitious shoots in Phyllanthus niruri, an anti-malarial plant as an initial effort towards its domestication. Fruits cultured on Murashige and Skoog (1962) basal medium (MS) supplemented with BAP had low germination (61%) due to seed coat imposed dormancy. The culture of nodal cuttings explants on BAP, kinetin or 2-isopentyl adenine (2iP) amended medium to avoid seed dormancy resulted in shoot regeneration without roots in all accessions with BAP producing the highest number of shoots (9.0). Subsequent inclusion of either 1-naphthalene acetic acid (NAA) or indole-3-butyric acid (IBA) in the BAP, kinetin or 2iP amended MS medium also produced only shoots. Leaf lobe explants cultured on only 2,4-dichlorophenoxy acetic acid (2,4-D) amended medium led to a significant calli development with 1 mg/L 2,4-D producing 100, 88.9 and 95.8% callus, respectively from Kwabenya, Kasoa and Aburi accessions. Subsequent transfer of calli to MS medium supplemented with 0.1 mg/L BAP led to calli growth (increase in weight) and morphogenic response depending on the concentration of 2,4-D in the induction medium. Only 55 and 25% of these calli from Kwabenya and Kasoa, respectively produced shoots while roots development was significantly higher ranging from 48 to 88.9%. These shoots did not survive ex-vitro acclimatisation due to hyperhydricity while those regenerated from nodal cuttings or seeds had high percentage survival. The high morphogenetic response of Phyllanthus niruri in vitro can be used to propagate this anti malarial plant and enhance its utilization in the treatment of malaria.Key words: Shoot regeneration, morphogenic response, Phyllanthus niruri, accessions

Effects of gamma irradiation and ethyl methane sulphonate on morphometric traits and prevalence of common viral diseases and whiteflies in cassava

Cassava ( Manihot esculenta Crantz) is an important staple and food security crop for millions of people in Africa. However, its nutritional value is limited; yet its productivity is constrained by several pests and diseases. Induced mutagenesis is one approach with the potential to overcome such biotic stresses. The objective of this study was to assess the variability in morphometric traits and prevalence of common viral diseases and whiteflies in cassava to different doses and concentrations of gamma irradiation and ethyl methane sulphonate (ems) treatments. The effects were assessed on seed germination and growth of stakes, as well as foliar viral disease symptoms and whitefly counts. Radio-sensitivity tests revealed LD50 for sprouting as 37.6Gy for \u3b3-irradiation and 0.08% for EMS treatment. There was notable decrease in sprout, epicotyl length, shoot height, petiole length and number of leaf lobes, with increasing \u3b3-ray doses and EMS concentrations. Contrastingly, total chlorophyll content increased with increasing doses of \u3b3-rays and EMS concentrations. Basing on foliar whitefly counts and disease symptoms, there was a general increase in susceptibility to whitefly infestation and cassava mosaic disease (CMD) incidence. Significantly varying levels of resistance or tolerance to whiteflies and CMD were observed among plantlets derived from irradiated and EMS treated stems, compared to the controls. These findings lay a foundation for more future research on breeding for various traits, including disease resistance in cassava using induced mutagenesis approach.Le manioc ( Manihot esculenta Crantz) est une culture de base et de la s\ue9curit\ue9 alimentaire importante pour des millions de personnes en Afrique. Cependant, sa valeur nutritionnelle est limit\ue9e; pourtant, sa productivit\ue9 est limit\ue9e par plusieurs ravageurs et maladies. La mutagen\ue8se induite est une approche ayant le potentiel de surmonter de tels stress biotiques. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la variabilit\ue9 des traits morphom\ue9triques et la pr\ue9valence des maladies virales courantes et des aleurodes du manioc en raison de l\u2019exposition \ue0 diff\ue9rentes doses et concentrations des traitements par l\u2018 irradiation gamma et \ue9thyl m\ue9thane sulfonate (EMS). Les effets ont \ue9t\ue9 \ue9valu\ue9s sur la germination des graines et la croissance des tuteurs, ainsi que sur les sympt\uf4mes de la maladie virale foliaire et le nombre des aleurodes. Les tests de radiosensibilit\ue9 ont r\ue9v\ue9l\ue9 que la DL50 pour la germination \ue9tait de 37,6 Gy pour l\u2019irradiation et de 0,08 % pour le traitement EMS. Il y avait une diminution notable de la pousse, de la longueur de l\u2019\ue9picotyle, de la hauteur des pousses, de la longueur du p\ue9tiole et du nombre des lobes foliaires, avec l\u2019augmentation des doses de rayons et des concentrations EMS. En revanche, la teneur totale en chlorophylle augmentait avec l\u2019augmentation des doses de rayons et des concentrations EMS. Sur la base des d\ue9nombrements foliaires des aleurodes et des sympt\uf4mes de la maladie, il y avait une susceptibilit\ue9 g\ue9n\ue9ralement accrue \ue0 l\u2019infestation des aleurodes et \ue0 l\u2019incidence de la maladie de la mosa\uefque du manioc (CMD). Des niveaux significativement variables de r\ue9sistance ou de tol\ue9rance aux aleurodes et \ue0 la CMD ont \ue9t\ue9 observ\ue9s parmi les plantules d\ue9riv\ue9es de tiges irradi\ue9es et trait\ue9es par EMS, par rapport aux t\ue9moins. Ces r\ue9sultats jettent les bases des autres recherches futures sur la s\ue9lection pour les divers caract\ue8res, y compris la r\ue9sistance aux maladies du manioc en utilisant une approche de mutagen\ue8se induite

In vitro regeneration of Vitellaria paradoxa from shoot tip explants

Shea tree (Vitellaria paradoxa) is an essential tree crop with great potential economic value mainly because of its seed oil (shea butter) which is of high demand for manufacturing assorted products in food, cosmetic, and rubber industries. Propagation of this species is, however, hindered by relative unavailability of seed (nuts), erratic seed germination, a long vegetative phase, and latex exudation from cuttings. Thus, another method of propagation through in vitro culture is recommended for rapid multiplication of shea genotypes for large-scale cultivation. In the present study, the effects of two cytokinins, namely, 6-benzylaminopurine (BAP) and kinetin (KIN), and one auxin, namely 1-naphthaleneacetic acid (NAA), on shoot and/or root induction in vitro were assessed at various combinations/concentrations. The inclusion of these growth regulators in the culture medium significantly improved (P < 0.05) shoot/root regeneration over the controls. The highest shoot regeneration percentage (100%) was obtained on Murashige and Skoog (MS) basal medium supplemented with 2 mg * dm^-3 KIN + 0.5 mg * dm^-3 NAA or 1.5 mg * dm^-3 KIN within 7/8 days of inoculation. This medium (2 mg * dm^-3 KIN + 0.5 mg * dm^-3 NAA) showed the highest mean shoot length of 3.24 cm. Compared to KIN, BAP was more effective in inducing vigorous shoot growth. However, rooting was induced only on MS medium modified with 1 mg * dm^-3 BAP + 0.5 mg * dm^-3 NAA. These findings can serve as baseline information for in vitro, commercial scale propagation of shea tree

Effects of gamma irradiation and ethyl methane sulphonate on morphometric traits and prevalence of common viral diseases and whiteflies in cassava.

Cassava (Manihot esculenta Crantz) is an important staple and food security crop for millions of people in Africa. However, its nutritional value is limited; yet its productivity is constrained by several pests and diseases. Induced mutagenesis is one approach with the potential to overcome such biotic stresses. The objective of this study was to assess the variability in morphometric traits and prevalence of common viral diseases and whiteflies in cassava to different doses and concentrations of gamma irradiation and ethyl methane sulphonate (ems) treatments. The effects were assessed on seed germination and growth of stakes, as well as foliar viral disease symptoms and whitefly counts. Radio-sensitivity tests revealed LD50 for sprouting as 37.6Gy for g-irradiation and 0.08% for EMS treatment. There was notable decrease in sprout, epicotyl length, shoot height, petiole length and number of leaf lobes, with increasing g-ray doses and EMS concentrations. Contrastingly, total chlorophyll content increased with increasing doses of g-rays and EMS concentrations. Basing on foliar whitefly counts and disease symptoms, there was a general increase in susceptibility to whitefly infestation and cassava mosaic disease (CMD) incidence. Significantly varying levels of resistance or tolerance to whiteflies and CMD were observed among plantlets derived from irradiated and EMS treated stems, compared to the controls. These findings lay a foundation for more future research on breeding for various traits, including disease resistance in cassava using induced mutagenesis approach