ABSTRACT
Aims: A procedure was developed for embryogenesis from embryo explants derived from mature seeds of freshly harvested Serenut 4T, Serenut 1R and Acholi-white groundnut cultivars representing the three broad groundnut botanical classifications. Methodology: This study explored the use of mature embryo axes as explants for somatic embryogenesis, and determined the factors that affect regeneration of three Ugandan groundnut cultivars. Freshly harvested mature seeds of the three groundnut cultivars were collected and the embryo explants were initiated on 3 media namely; Murashige and Skoog (MS) basal media with varying concentrations of the growth regulator 2,4-Dichlorophenoxy acetic acid (2,4-D); Chu N6 basal medium with vitamins (N6); and Callus Induction Medium (CIM). The shoot formation and elongation medium contained MS basal medium supplemented with indolebutyric acid (IBA) and 6- Benzylamminopurine (BAP) in isolation, and BAP in combination with a-naphthaleneacetic acid (NAA) and indoleacetic acid (IAA). For root induction, elongated shoots were transferred to MS medium supplemented with various combinations of NAA with IBA, BAP and a combination of IBA and Kinetin. Results and Conclusion: Different concentrations of 2,4-D elicited different callogenesis responses in the cultivars with Acholi white (Valencia botanical) and Serenut 4T (Spanish botanical) giving the optimal response at 5mg/l whereas Serenut 1R (Virginia botanical) showed best response at a concentration of 30 mg/l. N6 and CIM supported callogenesis in Acholi white (AW) and Serenut 4T only. In all cultivars, maximum root production was gained when using MS medium supplemented with NAA- 1 mg/l and IBA -2.0 mg/l. On the other hand, for Serenut 1R and Serenut 4T, BAP 2.5 mg/l; NAA 0.5 mg/l combination yielded higher shoot regeneration percentage whereas for AW BAP 3 mg/l; NAA 0.5 mg/l supported maximum shoot production.This is the first ever report of successful regeneration of the three groundnuts botanicals in Uganda. These results are likely to facilitate genetic transformation of three preferred Ugandan groundnut varieties.
ABSTRACT
The aim of this study was to optimize the in vitro preservation of yam genetic resources through reduction of the number of subcultures. Effects of different concentrations of activated charcoal (1 g.l-1, 2 g.l-1and 3 g.l-1) and temporary darkness were tested on the in vitro morphogenesis of three beninese yam accessions (Dcr28, Dcr164 and Da93G1). Galzy glutamine was used as basis culture medium and explants were microcuttings obtained from four months old plantlets. The results indicated that the activated charcoal, alone or combined with temporary darkness has an inhibitory effect on the aerial organs formation but favors root development with a greater mean number of root shoots (9.3±1.67 with 3 g.l-1 of activated charcoal) than the subtract without activated charcoal (2.5±0.17). A significant interaction was noted between accessions and concentration of activated charcoal indicating genotypic variability from the activated charcoal effect. The different accession plantlets growing in high concentration of activated charcoal culture media combined with temporary darkness were vigorous after eight month without subculture and subsequently allow doing one subculture per year.
ABSTRACT
Objetivou-se, neste trabalho, estudar a indução da organogênese em segmentos foliares e internódios de videira cv. Merlot, utilizando diferentes tipos e concentrações de citocininas. O meio de cultura usado foi o MS com redução da metade dos sais e vitaminas, suplementado com 1 µM de ácido naftalenoacético (ANA). Os tratamentos consistiram das concentrações de 2,5; 5,0 ou 10 µM de 6-benzilaminopurina (BAP) ou 1-fenil-3-(1,2,3,-tiadiazol-5-il) uréia (TDZ). Foram avaliados o porcentual de formação de gemas, calos, oxidação e raízes, além do número de raízes e gemas. Aos 60 dias de cultivo in vitro foi observado que concentrações de 2,5-10 µM de BAP e TDZ permitem que segmentos foliares oxidem e não induzam à oxidação nos internódios. O nível de 5 µM de TDZ favore o maior porcentual de formação de gemas em internódios e segmentos foliares não apresentam capacidade para formar gemas nos níveis de 2,5-10 µM de BAP ou TDZ. O uso de BAP nas concentrações de 2,5 e 5 µM favorece altos porcentuais de enraizamento em internódios. O uso de TDZ no nível de 2,5 µM promove elevada taxa de formação de calos em internódios. Os internódios apresentaram maior capacidade organogênica do que os segmentos foliares.
The objective of this work was study the induction of organogenesis on leaf segments and internodes of grapevine cv. Merlot using different types and concentrations of cytokinins. MS half strength culture medium supplemented with 1 µM naftalenoacetic acid (NAA) was used. The treatments consisted of the concentrations of 2.5; 5.0 or 10 µM 6-benzilaminopurine (BAP) or thydiazuron (TDZ). The percentage of buds, callus, oxidation and roots as well as the number of roots and buds were evaluated. After 60 days of in vitro culture it was observed that the concentrations of 2.5-10 µM BAP or TDZ oxidize leaf segments and do not induce oxidation in the internodes. The level of 5 µM TDZ promote the largest formation of buds from internodes and leaf segments do not have capacity to form buds at the levels of 2,5-10 µM BAP or TDZ. The use of BAP at the concentrations of 2.5 and 5 µM promote high rooting percentage of internodes. TDZ at the level of 2.5 µM promotes high rate of callus formation in internodes. Internodes presented larger organogenic capacity than leaf segments.