Assessing provenances of Moringa oleifera L. for salt tolerance and low methane emission : a thesis presented in the partial fulfilment of the requirements for the degree of Master of Science in Plant Breeding at Massey University, Palmerston North, New Zealand

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Massey University
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Moringa oleifera has a high nutritional content and easy propagation. It is well known worldwide where it grows best in tropical and sub- tropical environments. M. oleifera originated from Northern India, but plants can be found growing in Guyana, South America, where most of the agricultural lands are on the coastal plains and sea water intrusion is common. The objective of this study was to carry out a pre-breeding characterization of six M. oleifera provenances, four from Guyana and two from India for salt tolerance and their effect on rumen methane emissions compared with high quality pasture species. A salt tolerance trial using the six provenances was done in a greenhouse at the Massey Plant Growth Unit, Batchelar Road, Palmerston North. The experiment was set up in a randomised complete block design, containing five blocks and three levels of salinity (0 mM, 52 mM and 156 mM NaCl). For each treatment ten seeds were sown in two pots and the salt treatments were applied by immersing pots for 30 minutes in the respective salt solutions every seven days for 21 days. Plant growth and net photosynthesis were measured during the stress period, chlorophyll content measured before and after salt stress, and biomass measurements along with sodium concentration in leaves, were taken at the end of the experiment. Methane and total gas production were measured using an in vitro batch culture system. Two experiments were done, a preliminary screening using oven dried M. oleifera planted in field and greenhouse, and a main experiment using the six provenances, a composite sample and M. oleifera leaves from greenhouse. Both experiments compared the different M. oleifera sources with high quality ryegrass and white clover. Real time gas production was recorded for 48 hours, total gas production, methane analysed at 12 and 24h. Short chain fatty acids concentration were also determined at the end of the fermentation. The preliminary experiment showed that M. oleifera leaves grown in field and greenhouse have lower gas and methane production compared with ryegrass, but similar to white clover. The differences were driven by a high production of propionic and butyric acids. The six M. oleifera provenances also produced less methane than ryegrass but similar to white clover at 12 and 24 hours after the start of fermentation. Salinity screening of the six M. oleifera provenances showed a significant (P < 0.001) reduction in plant growth at 156 mM NaCl. There was an increase in sodium in photosynthetic active leaves as salt stress increased. However, at 52 mM NaCl plants survived and showed no significant difference in root and above ground plant biomass when compared with the control. Net Photosynthesis was also not significantly affected by the application of 52 mM NaCl salt stress and there was also no significant reduction of plant percent dry weight at 52 mM NaCl when compared with control plants. Future work should include screening of more M. oleifera provenances for salinity tolerance and determination of the genetic diversity among these provenances. This would help determine the origin of the seeds sourced from King Seeds (Katikati, New Zealand) and their relation to the seeds sourced from Guyana and India. Cold tolerance screening should also be carried out using provenances from Northern India, which will help widen the gene pool for the creation of a base population for breeding programmes.