Crop Protection & Environmental Biology
Permanent URI for this communityhttps://repository.ui.edu.ng/handle/123456789/490
Browse
7 results
Search Results
Item Clean breeder seed yam tuber production using temporary immersion bioreactors(International Institute of Tropical Agriculture (IITA), Ibadan, 2017) Balogun, M.; Maroya, N.; Taiwo, J.; Ajayi, A.; Ossai, C.; Lava, K.; Pelemo, O.; Aighewi, B.; Asiedu, R.Item Manual for clean foundation seed yam production using aeroponics system(International Institute of Tropical Agriculture (IITA), Ibadan, 2017) Maroya, N.; Balogun, M.; Aighewi, B.; Lasisi, J.; Asiedu, R.Item Effects of basal medium and plant growth regulator regimes on meristem and nodal cultures in white yam (D. rotundata)(International Institute of Tropical Agriculture, Ibadan, Nigeria, 2017) Ajayi, A.; Balogun, M.; Maroya, N.; Asiedu, R.Item Relative efficiency of positive selection and tissue culture for generating pathogen-free planting materials of yam (dioscorea spp.)(2017) Balogun, M.; Maroya, N.; Augusto, J.; Ajayi, A.; Kumar, L.; Aighewi, B.; Asiedu, R.Yams are staples in West Africa. They are propagated from tubers in an informal seed system. This encourages a build-up of diseases, and necessitates the rapid development of a formal seed system where certified seeds are functional. Although few reports exist on the use of meristem culture to generate pathogen-free yam, the success rate for the most economically important species in the sub-region, Dioscorea rotundata, for the most prevalent viruses is inadequate. To generate pathogen-free yam planting materials, the relative efficiency of tis¬sue culture and positive selection was compared. Twenty-one asymptomatic yam plants were positively selected from 8187 stands of five landraces. Five of these stands were tested virus-negative by multiplex polymerase chain reaction (PCR) for Yam mosaic virus (YMV), Yam mild mosaic virus (YMMV) and Cucumber mosaic virus (CMV), and by PCR for the genus Badnavirus (BV), giving 0.08% success. Single nodes of the positively selected stands were used to establish in vitro plantlets, which were screened onto bacteriological indexing medium. The same was done for meristem- and node-derived plantlets of the improved variety TDr 95/19158. Incidence of endophytes ranged from 18 to 32% in the nodal plantlets while it was 0% in the meristem-derived plantlets. The effect of meristem culture combined with thermotherapy on the virus infection status was deter¬mined using virus-tested, one week old in vitro plantlets of eight improved genotypes. These in vitro plantlets were incubated at 36 ± 0.5°C and 16 h photoperiod for 21 days, after which meristems were excised, regenerated into plantlets and re-tested for viruses. Seventy-three percent of the samples were recovered from YMV but the effect on BV was inconsistent. Positive selection can be used as a palliative in generating quality declared seed but meristem culture combined with thermotherapy is more efficient for generating certified seed tubers of yam.Item Improved propagation methods to raise the productivity of yam (dioscorea rotundata poir.)(Springer, 2015-07) Aighewi, B.; Asiedu, R.; Maroya, N.; Balogun, M.White Guinea yam (Dioscorea rotundata Poir.) is an important staple to millions of people in West Africa. Obtaining good quality planting material for yam cultivation is a major challenge. Multiplication ratios are low, and seed tubers are prone to contamination with pests and pathogens in the traditional systems of production. Some approaches to producing quality seed of yam are as follows: farmers select small whole tubers from a ware crop harvest; stimulate the production of seed tubers by ‘milking’ ware tubers while the leaves of the plant are still green (double harvest system); cut ware tubers into setts about the same sizes as regular seed tubers; or use the ‘Anambra’ system where smaller setts are cut and used to produce seed tubers. New methods that have been developed to address some of the challenges of quantity and quality of seed tubers are not yet widely applied, so farmers continue to use traditional methods and save seed from a previous harvest to plant the ware crop. This document presents an overview of traditional and modern methods of seed yam production and gives a perspective for the future. Among the modern methods of seed yam production, only the minisett technique, which uses 25–100 g tuber pieces, is currently used at farmer level, although on a limited scale. While tissue and organ culture techniques are the most rapid methods of multiplying disease free propagules, their limitations include high costs, need for skilled personnel and specialized equipment. The aeroponics and temporary immersion bioreactor methods of producing seed yam are relatively new, and still need more research. To build and sustain a viable seed yam production system, a multiplication scheme is required that combines two or more methods including tissue culture for cleaning the seed stock.Item Yam propagation using 'aeroponics' technology(2014) Maroya, N.; Balogun, M.; Asiedu, R.; Aighewi, B.; Kumar, L.; Augusto, J.Aims: To study yam propagation and seed yam tuber production in aeroponics system. Study Design: The experiment was conducted in a randomized complete block design and treatments were replicated three times. Place of Study: This experiment was carried out at the International Institute of Tropical Agriculture Headquarters at Ibadan in Nigeria. Methodology: The experiment tested fresh vine cuttings of five yam genotypes of two species in an aeroponics system. Three genotypes of Dioscorea rotundata (TDr 89/02475, TDr 89/02665 and TDr 95/18544) and two yam genotypes of D. alata (TDa 98/01176 and TDa 291) were evaluated. Results: Vines of both D. rotundata and D. alata rooted within 2 weeks in aeroponics system. The rooting of vine cuttings varied significantly among genotypes with a maximum of 98% for TDa 98/01176 and a minimum of 68% for TDr 89/02665. Mini-tubers harvested after 4 months of growth in aeroponics weighed between 0.2 and 2.7g. A second harvest 6 months later gave mini-tubers of up to 110g. The analysis of variance showed significant difference (P<0.05) among genotypes for rooting at 2 weeks after vine planting, number of plant surviving at 90 days after planting and percentage of plants with bulbils. The best genotypes were TDr 95/18544 and TDr 89/02665 for survival at 90 days after vine planting and percentage of plant producing bulbils in the aeroponics system respectively. Conclusion: This study revealed that yam genotypes performed differently in aeroponics system for vine rooting and production of mini-tubers and bulbils.Item Status and prospects for improving yam seed systems using temporary immersion bioreactors(Academic Journals, 2014-04) Balogun, M. O.; Maroya, N.; Asiedu, R.Yam production is constrained by scarcity of clean seed, pests, diseases and low soil fertility in the informal seed system, which is still operational, causing up to 90% yield losses. Although meristem culture can be effective for producing healthy seed yam, its use is limited by slow rate of regeneration and propagation in conventional tissue cultures. In most crops tested, temporary immersion bioreactor systems (TIBs) increased propagation rates. To determine the potential of TIBs in improving the yam seed system, 23 databases were consulted and three returned a total of eight publications with only 2 for Dioscorea rotundata-cayenensis. Both plantlets and microtubers can be produced in TIBs, which will facilitate production of quality breeder, foundation and certified seeds and fast-track genetic improvement and the evolution of a formal from informal seed production system. Control of contamination, direct use of field explants, culture of micro-explants like immature embryos and anthers, increasing the size of microtubers produced and standardization for various economically important yam genotypes are knowledge gaps that require immediate research attention. No report has put a cost on yam TIBs, but it will be necessary to use cost-effective TIBs to encourage integration public-private partnerships into emerging formal seed system.