Browsing by Author "Grout, B. W."

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Altered response to biotic and abiotic stress in tissue culture-induced off-type plants of East African Highland Banana (Musa AAA East Africa)
(Asian Network for Scientific Information, 2008) Msogoya, T. J.; Grout, B. W.
This study was conducted to investigate black sigatoka disease and drought stress responses of off• type plants derived from shoot-tip micropropagation of East African highland banana (Musa AAA East Africa) landrace Uganda. Results showed that the off-type plants were more (p<0.05) tolerant to black sigatoka disease with the infection index of 17 .5% compared to 30.1 and 22.8% of the micropropagation (Ml') derived phenotypically normal plants and Conventional Propagation (CP) derived plants with no tissue culture history in their ancestry, respectively. On the contrary, the off-type plants were more (p<0.05) vulnerable to water stress with leaf senescence of 87.7% at soil water deficit of 630 millibars. The leaf senescence of the 1v1.P and CP derived plants at the same soil moisture deficit was 79.5 and 66.7%, respectively. During this stress period each off-type plant produced one sucker, while the true-to-type plants were unable to do so. Leaf structural analysis revealed that the off-type plants had higher (p<0.05) stomatal density of 16.0 mm-2 of the upper leaf surface. Conversely, the MP and CP derived plants had each 12.3 and 11.0 stomata mm ? of the leaf upper surface. Similarly, the off-type plant leaves were more hydrophobic with higher (p<0.05) epicuticular waxiness of 684.6 μg cm ". The epicuticular wax content of the 1v1.P and CP derived plant leaves was as low as 646.2 and 647.7 μg cm ", respectively. The water stressed off-type plant leaves exhibited higher (p<0.05) membrane damage with ion leakage of 168.2 μS cm" compared to 139.7 and 136.8 μS cm" of the 1v1.P and CP derived plants. Moreover, the water stressed leaves of the off-type plants had enhanced total antioxidant activity of 5.17 M trolox equivalent per milligram proteins, whereas the total antioxidant activity of the MP and CP derived plant leaves was as low as 3. 76 and 3.67 M trolox equivalent per milligram proteins, respectively.
Cytosine DNA methylation changes drought stress responses in tissue culture derived banana (Musa AAA- East Africa) plants
(Journal of Applied Biosciences, 2011) Msogoya, T. J.; Grout, B. W.
Tissue culture derived plants are often vulnerable to abiotic stresses but mechanisms underlying such responses are hardly known. This study was conducted to determine mechanisms underlying drought stress vulnerability of in vitro derived banana cv. ‘Uganda’. Methodology and results: Suckers of in vitro derived off-type, in vitro micropropagation (MP) derived normal plants and conventionally propagated (CP) plants with no tissue culture history in their ancestry were collected in the field at Sokoine University of Agriculture and planted in 20-litre containers for drought stress evaluation. The mechanisms underlying the drought stress vulnerability were determined when banana plants reached 1.5 m tall based on leaf global cytosine DNA methylation, stomatal density and leaf senescence. Global cytosine DNA methylation was determined from cigar leaves by a reversed phase HPLC analysis. Leaf stomatal density was determined as the number of stomata per unit area of both upper and lower leaf surfaces. Leaf senescence was estimated as a number of leaves with dying margins when soil moisture level decreased to minus 630 millibars. The off-type and MP derived plants had lower (P < 0.05) global cytosine DNA methylation of 11.3 and 17.5 % compared with 22.5 % of the CP derived plants. On the contrary, the off-type and MP derived plants had higher stomatal density of 78.2 and 78.8 stomata per mm2 on the lower leaf surface compared to 72.0 stomata per mm2 of the CP derived banana plants. The leaf senescence of the off-type and MP derived plants was significantly (P < 0.05) higher with 87.7 and 79.5 % compared to 66.7 % of the CP derived plants at soil moisture of minus 630 millibars. Conclusion and application: These findings provide evidence that tissue culture process increases the vulnerability to water stress of in vitro banana regenerants as a consequence of increased leaf stomatal density which is possibly under the control of cytosine DNA hypomethylation. The vulnerability of the in vitro derived banana cv. ‘Uganda’ limits the use of tissue culture derived planting materials among small-scale farmers with limited water resource and irrigation facilities but provides an opportunity for further studies to minimise water stress susceptibility of in vitro derived banana suckers.
Field performance of micropropagated east African banana (musa AAA east Africa) in the eastern zone of Tanzania
(Asian Network for Scientific Information, 2006) Msogoya, T. J.; Maerere, A. P.; Grout, B. W.
This study was conducted to evaluate yield performance of micro-propagated CM.Pd) East African cooking banana (Musa AAA East Africa) cv. Uganda and cv. Bukoba in the Eastern zone of Tanzania. Plant size of MPd cv. Bukoba was significantly bigger (p
Karyotypic and 2C nuclear DNA size instability in vitro induced off-types of east African highland banana (musa AAA east Africa)
(Asian Network for Scientific Information, 2008) Msogoya, T. J.; Grout, B. W.; Roberts, A.
This study was conducted to determine chromosome number and 2C nuclear DNA content in tissue culture induced off-type banana (Musa AAA East Africa) landrace Uganda with tolerance black sigatoka disease, susceptibility to water stress, sparsely black-blotched pseudostems, taller pseudostems, late fruit maturation, altered inflorescence and higher fruit dry matter content. The off-type banana appeared to have higher (p<0.05) frequency of31 and 32 chromosomes at 15.1 and 13.6%, respectively. Conversely, the frequency of 31 and 32 chromosomes was 12.0 and 9.6% for the micropropagation (.MP) derived phenotypically normal plants and 11.8 and 9.5% for the Conventionally Propagation (CP) derived plants with no tissue culture history. Moreover, the off-type banana had lower (p<0.05) leaf2C nuclear DNA amount of 1.72 pg, whilst the .MP and CP derived plants had 1.81 and 1.82 pg, respectively.
Performance of micropropagation-induced off-type of East African highland banana (Musa AAA - East Africa)
(Journal of Animal & Plant Sciences, 2011) Msogoya, T. J.; Grout, B. W.; Maerere, A. P.
Tissue culture derived off-type plants with both good and poor field performance have been reported in banana and researchers have viewed the variants as a new source of genetic variability for crop improvement. In vitro micropropagation of East African highland banana (Musa - AAA East Africa) cv.’ Uganda’ resulted in high incidence of off-type plants. This study was conducted to evaluate the performance of the in vitro derived off-type banana in comparison with the in vitro micropropagation (MP) derived normal banana and conventionally propagated (CP) banana with no tissue culture history in its ancestry as controls. The evaluation of the off-type was carried out in 2005/2007 at Sokoine University of Agriculture based on number of days to plant flowering and fruit maturation, yield, fruit quality and shelf life. Results showed that the off-type banana produced significantly (P < 0.05) higher yield with bigger bunches and fruits of 52.2 t/ha, 21.1 kg per bunch and 125.3 g per fruit compared with 40.7 t/ha, 16.5 kg and 109.5 g of the MP derived normal banana and 45.7 t/ha, 18.5 kg and 118.3 g of the CP derived banana, respectively. The off-type fruits were significantly (P < 0.05) firmer with higher dry matter content of 12.4 kg/cm2 and 33.7 %. The firmness and dry matter content of the MP derived normal banana were 8.5 kg/cm2 and 20.0 %, and those of the CP derived banana were 8.9 kg/cm2 and 21.1 %, respectively. The off-type fruits had significantly (P < 0.05) longer shelf life of 17 days compared with 7.2 and 7.0 days of the MP and CP derived normal banana, respectively. However, the off-type banana was constrained by a significantly (P < 0.05) delayed flowering by one month and maturation by two months compared with the trueto- type banana. The observed agronomically desirable characters of the off-type banana underscore the potential of tissue culture technology as an alternative strategy for creation of genetic variability and improvement of East African highland banana.
Reduction in genome size and DNA methylation alters plant and fruit development in tissue culture induced off-type banana (Musa spp.)
(JAPS, 2011) Msogoya, T. J.; Grout, B. W.; Roberts, A.
Shoot tip in vitro micropropagation of banana (Musa AAA East Africa) cv.’ Uganda’ resulted in off-type plants with an altered plant and fruit development. This study was carried out to determine epigenetic mechanisms underlying the altered plant and fruit development of the in vitro derived off-type banana. The off-type banana was compared with in vitro micropropagation (MP) derived normal banana and conventionally propagated (CP) banana plants with no tissue culture history in their ancestry as controls. Plant development was estimated based on plant height, girth and number of days from planting to flowering. Fruit development was measured as the number of days from flowering to fruit maturation and senescence. Mechanisms underlying the altered plant and fruit development were determined based on global cytosine DNA methylation and 2C nuclear DNA content. Leaf cytosine DNA methylation and 2C nuclear DNA content were determined using reversed phase HPLC and flow cytometer, respectively. Results showed that the off-type banana was significantly (P < 0.05) taller and delayed to flower compared with the MP and CP derived banana. Similarly, the fruits of the off-type banana had significantly (P< 0.05) longer maturation, ripening and senescence periods than those of the true-totype fruits. The offtype derived plants had lower (P < 0.05) leaf global cytosine DNA methylation and 2C nuclear DNA amount compared with the MP and CP derived plants. These findings suggest that the altered plant and fruit development of the of-type banana are possibly under the control of reduced cytosine DNA methylation and nuclear DNA content. Further studies are required to identify specific genes which affect plant and fruit development upon undergoing demethylation.