THE RESPONSE OF TEN NEWLY RELEASED CASSAVA VARIETIES FOR DIRECT PLANTING USING 2 & 4 NODE STAKES FOR CASSAVA STEM MULTIPLICATION.   Njoku, S. C., Egesi, C. N., Eke-Okoro, O.N., Ikeogu, U. N., and Ebeniro, C. N. ABSTRACT Cassava (Manihot esculenta Crantz), an important source of energy in the diets of most tropical countries is rapidly evolving from a subsistence to a commercial and industrial crop. The crop has low multiplication ratio which poses a challenge in the efficient distribution of improved varieties to farmers and other users due to insufficient planting materials. Two year experiment was carried out to evaluate the effect of direct planting of two and four node per cassava planting stake on stem yield and other agronomic attributes. The study was carried out in 2008/2009 and 2009/2010 cropping seasons at the National Root Crops Research Institute (NRCRI) research farm, Umudike. Planting materials consisted of ten newly improved cassava varieties (TMS98/0505, TMS98/0510, TMS98/0581, TMS97/2205, TMS92/0057, TMS92/0326, TME419, NR87184, TMS98/0002 and TMS96/1632) collected from the germplasm of NRCRI, Umudike and two farmers preferred varieties (NR8082 and TMS30572) were used as checks. Two and four node per stake of each variety were planted in 1m x 0.25m planting distance in a plot size of 5x4 meters in a randomized complete block trial replicated three times. Analysis of variance showed that the number of nodes/stake had significant effect (P<0.001) on all traits except number of root rots and stalk weight. There was also high significant variation due to variety and seasonal effects. Four node/stake planting materials had better mean performance over two nodes for all the attributes measured except root rot. In addition, cassava attributes measured were better in 2010 than 2009 cropping seasons. Most of the newly released varieties had better performance than the check varieties. Direct planting of two and four node cassava stakes therefore has a great potential for rapid cassava stem multiplication. Use of 4 node cuttings however combined rapid stem multiplication with high root yield among the varieties.   Keywords: Cassava, multiplication ratio, improved varieties, planting materials, germplasm, nodes and stakes. INTRODUCTION: Cassava (Manihot esculenta Crantz) also known as ‘tapioca’ or ‘manioc’ is one of the major crops grown in Nigeria. About 90% produced is used for food, animal feed, industrial, Pharmaceutical and unquantifiable quantities for export (Eke-Okoro 2008). Diseases and pests in cassava can bring about yield losses that can be as high as 90% in highly susceptible varieties most especially cassava mosaic disease (CMD) (Gibson et al., 1996; Otim-Nape et al., 1997). Control measures include host plant resistance and cultural measures. One of such cultural control strategies is the use of virus free stem cuttings as planting materials ( Ogbe et al 2007) Another major constraint to increase cassava production is the problem of insufficient planting materials. Cassava has a slow rate of propagation, only 10—30 times per year (Cock et al., 1976). About 50% of Nigerian population wants to grow cassava for export purpose but can’t achieve this with the few planting materials available for newly released varieties. Present emphasis on cassava production for diversified uses, cassava transformation agenda of Nigerian government and high export values has provoked great demand for planting materials of the improved cassava varieties in Nigeria. For now, existing package seems not to have provided adequate solution to the problem of planting materials always encountered by farmers. There is therefore need for development of packages that will ensure rapid multiplication of planting material on the farmer’s field through direct planting of cassava stakes with 2 and 4 nodes in the field for stem production. MATERIALS AND METHOD The study was carried out in two cropping seasons (2008/2009 and 2009/2010) at Research Farm of National Root Crop Research Institute (NRCRI), Umudike (Latitude 050 29’N, Longitude 070 33’) in South-eastern Nigeria. The soil at the experimental site was classified as Typical Palenduct derived from coastal plain (Chukwu and Ifenkwe 1996). The top soil (0-20) texture of the soil is sandy loam. There are two distinct seasons, the rainy season starts in April and ends in October while the dry season last from November to March. The rainy season has a bimodal distribution with peaks in July and September, typical of South-western and south-eastern zones of Nigeria. Ten newly improved cassava varieties (TMS98/0505, TMS98/0510, TMS98/0581, TMS97/2205, TMS92/0057, TMS92/0326, TME419, NR87184, TMS98/0002 and TMS96/1632) and two check varieties (NR8082 and TMS30572) were used in this study. Each variety was planted directly in the field using 2 and 4 node stakes in a plot size of 5x4m in a randomized complete block design trial replicated three times. All the necessary agronomic data were collected and subjected to analysis of variance (ANOVA) using Genstat Discovery edition. RESULTS AND DISCUSSION The ANOVA showed each of variety, number of nodes and year as well as variety x year interaction had significantly effect (P<0.05) on all the attributes studied. The 4-node stake direct planting had a higher mean performance than 2-node stakes for all the parameters (Table 1). Average establishment percentage from the study stood at 70.31%, (78.8% in 4-node and 61.8% in 2-node stakes). Lozano et al. (1977) reported that use of 1-3 nodes has the disadvantage of poor sprouting rate due to rapid dehydration. However, the 2-node and 4-node stakes had high sprouting rates in this study. The 4-node stakes had higher sprouting than 2-node stakes under the humid forest of Umudike. This is in agreement with earlier reports (Dahniya and Kallon, 1984). 4-node stakes gave an average standard stem bundle yield (50 stems of 1m length) of 5.22 bundles/plot? while 2-node stakes gave 2.2 bundles/plot? Also, root yield (t/ha) and number of roots increased with number of nodes of cassava stakes. The increase in the number of nodes would have resulted to increased adventitious/nodal roots which in turn resulted in higher establishment or survival rate and higher root yield as recorded in this study. Differences in year performance showed that 2009 had higher mean performance for establishment percentage, number of bundles and root yield (t/ha) while the number of roots per plot was higher in 2008 than in 2009 cropping seasons. This could be due to differences in weather conditions between the two years. Varieties’ responses to 2-node and 4-node stakes were significantly (P<0.05) different. Cassava varieties used had better performance with 4-node than 2-node stakes for all the attributes. Mean variety performance however, showed that variety NR87184 could be selected for good establishment and stem yield (number of bundles) and TMS 96/1632 for root yield. Table 1: Mean attribute performance of cassava varieties in 2-node and 4-node stakes Number of nodes Variety Establishment Number of bundles Number of roots Fresh root yield (t/ha) 2N NR8082 47 1.96 52 35.95 NR87184 71 3.08 80.85 52.44 TME419 2.25 48.8 20.54 TMS30572 53.68 61.65 29.14 TMS92/0057 61 2.54 78.5 45.83 TMS92/0326 29.68 46.65 26.6 TMS96/1632 79.68 2.17 100.3 45.17 TMS97/2205 75.34 1.38 93 34.57 TMS98/0002 70.34 1.79 75.35 40.14 TMS98/0505 92 3.17 43.47 TMS98/0510 37.68 1.54 52.65 36.42 TMS98/0581 72.34 80.35 50.7 MEAN 61.8 2.2 70.91 38.41 4N 79 3.88 86.15 53.34 96.34 5.42 158.65 56.8 82 4.88 87.35 47.79 68 3.29 43.05 73 4.42 107.3 43.94 69 4.58 110.8 36.67 80.66 4.25 174.8 71.17 86.34 2.92 124.65 46.38 88 90.65 44.03 67 5.08 85.2 64.74 4.17 77.8 47.3 72 115.85 65.23 78.8 5.22 107.88 51.7 70.31 3.71 89.4 45.06 LSD0.05 (nodes) 6.62 0.27 8.74 3.36 A (2 nodes) C (harvested tubers) B (4 nodes) Fig. 1: Sample of 2, 4 and harvested tuber from a variety (TMS 98/0581). CONCLUSION Direct 2- node and 4-node planting in the humid rainforest is a good technology that can help to meet the current demand for planting materials by cassava farmers in Nigeria. However, 4-node stake is recommended for optimum stem and root yield production.   ACKNOWLEDGEMENT We acknowledge National Root Crops Research Institute (NRCRI), Umudike, Nigeria for providing the fund and enabling environment for this study. The fund for attending this conference was provided by Bill and Melinda Gates Foundation through the organizers of GCP21. REFERENCES Chukwu, G.O and G.E Ifenkwe (1996). An edaphological approach to biodiversity conservation in Ikwuano Local Government Area of Abia State: Implication for agrotechnology transfer proceedings. 5th Annual Conference of the Nigerian Society for biological conservation. Umudike,pp 91-94. Cock, J.H., Wholey, D.W., and Lozano, J.C. 1976. Rapid propagation system for cassava. Cali, Colombia, CIAT. 10 p. Dahniya, N.T and Kallon, S. N. 1984. Rapid multiplication of cassava by direct planting. In: Tropical root crops: symposium of the International Society for Society for Tropical Root crops-African Branch held in Douala, Cameroon, 14-19 August 1983. Ottawa, Ont., IDRC, 1984. Pp 53-54. Eke-okoro, O.N, Ogbe, FO, Ano, A.O, Akinpelu, A and Amanze, N.J. 2008. Determination of optimium rate of agrolyzer as supplement to NPK fertilizer and poultry. Manure for cassava production in Nigeria. NRCRI Umudike. Nigeria. Gibson, R.W., Legg, J.P. and Otim-Nape, G.W. 1996. Unusually severe symptoms are a characteristic of the current epidemic of mosaic virus disease of cassava in Uganda. Ann. Appl. Biol. 128: 479–490. Lozano, C., Toro, C., Castro, A., and Bellotti, A.C. 1977. Production of cassava planting material. Cali, Colombia, CIAT, Series GE-17. Ogbe, F. O. and G. Asumugha (2008) National Root Crops Research Institute Umudike Annual Report. Otim-Nape, G.W., Bua, A., Thresh, J.M., Baguma, Y., Ogwal, S., Ssemakula, G.N., Acola, G., Byabakama, B.A., Colvin, J., Cooter, R.J. and Martin, A. 1997. Cassava Mosaic Virus Disease in East Africa and its Control. Natural Resources Institute, Chatham, UK, 100 pp.