Vine Cutting Propagation in Four Varieties of Yam Using Different Planting Media

By Gbadamosi, A.E., Ajayi, A.T. and Osekita, O.S. 

Yams (Dioscorea spp), are one of the most  important staple crops in West Africa. They belong to the family Dioscoreaceae,  which produce economically important tubers  and bulbils. They are vegetatively  propagated by small whole tubers or pieces (>200  g) of tubers. Yam  (Dioscorea spp.) originated from Africa and Asia  and later spread to other parts of the world. There are many cultivars of yam,  though only six are important as staple foods in  the tropics. The economically important species  grown are Dioscorea rotundata (white yam),  Dioscorea alata (water yam), Dioscorea bulbifera (aerial yam), Dioscorea esculenta (Chinese yam)  and Dioscorea dumetorum (trifoliate yam).

Yam is very important in West Africa where  approximately 60 million people individually obtain huge calories of energy of about 800 KJ  per day; and especially in  Nigeria where it is massively grown and serves as  an indigenous source of food among the people. Most of the  world’s annual production of the crop, running  into over 27 million tons comes from Nigeria; hence, sustainable production and  utilization of the crop are important steps in enhancing food security and alleviating poverty  particularly in West Africa. 

The tuber (edible part of yam) serves as the  conventional propagules of the crop. Thus, about 30% of the previous harvest is  normally utilized to raise a new crop during a new  planting season. In this regard, some marketable  tubers must be reserved for planting making the  cost of planting material to be more than 33% of the total outlay for yam production, hence, the  need to improve the rate of yam multiplication. Yam propagation also  faces difficulties that arise from poor sprouting and  sensitivity to moisture stress in the soil despite the  advancements in the yam mini sett technology, a  condition that has placed the crop under threat in  many traditional areas of production.

For the distribution of high quality and improved  varieties of yam, techniques of rapid multiplication and devoid of contaminants are  desirable. Propagation using vine cuttings is one  of such techniques with the following proven  merits. First, it excludes transfer of nematodes to  seed tubers. Second, it reduces usage of tubers for  seed production and third, it produces whole mini  tubers which promise high sprouting rate and  uniformity compared with mini-setts. Media like  carbonized rice husk have produced mini tubers  of Dioscorea alata of up to 3 g in weight by vine  cuttings with about 63% of mini tubers sprouting  after 77 to 105 days of storage. Shiwachi et al in  2005 and Kikuno et al. in 2006 have achieved  greater success in seed tuber production through  vine cuttings. Root development by vine cuttings of yam has  been successful but growth and tuber production  were limited.  Stimulation of development of small tubers and  significant enhancements of number of roots has  been achieved via the treatment of vines of 

Dioscorea rotundata in indole butyric acid (IBA). This approach is very  expensive due to the high cost and scarcity of hormones to farmers. Hence, methods for  successful rooting of yam vines without the use of synthesized auxins are required to enhance  adoption of vine cutting techniques by farmers in  the developing countries. Matsunmoto et al.  in 2013 reported that in vine cuttings of Dioscorea  alata, rooting rate decreased by the increase in age of the mother plant. Up to 3 months old plants  showed more than approximately 80% of rooting  rate of vine cuttings while 4 and 5 months aged  plants showed less than 80% of rooting rate.  There is a possibility of vine cutting techniques in  yam using natural materials which can be adopted  by farmers. About 5% of rice straw ash enhanced rooting rate, number  of roots and tuber formation from vine cuttings  of yam.  

The objective of this research, which was to evaluate the  potential of mini tuber production, through vine cutting propagation techniques on three local  varieties of white yam (Dioscorea rotundata Poir.)  and one variety of water yam in various  propagation media, has already been carried out by the authors.

Gbadamosi, A.E., Ajayi, A.T. and Osekita, O.S. Vine Cutting Propagation in Four Varieties of Yam (Dioscorea Spp) Using Different Planting Media. Ife Journal of Science vol. 21, no. 2 (2019)

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