PRELIMINARY EVALUATION OF BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdc) FOR GROWTH AND REPRODUCTIVE CHARACTERISTICS IN OWERRI SOUTHEASTERN NIGERIA

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1 PRELIMINARY EVALUATION OF BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdc) FOR GROWTH AND REPRODUCTIVE CHARACTERISTICS IN OWERRI SOUTHEASTERN NIGERIA Adikuru *, N. C., Francis, A. A., Anyanwu, C. P., Onwubiko, N. C. and Alagba, R. A. Department of Crop Science and Technology Federal University of Technology, PMB 1526 Owerri Imo State, Nigeria , ABSTRACT Ten (10) accessions of Bambara groundnut were evaluated in the field to identify those with promising growth characteristics under the humid environment of Owerri in Southeastern Nigeria. The experiment was laid out in a randomized complete block design and replicated three times. The vegetative growth parameters measured were plant height, number of leaves, number of branches, root dry matter and shoot dry matter, while reproductive and yield parameters were days to first flower, days to 50 % flowering, number of fresh pods and weight of fresh pods. Significant differences were observed among the accessions at the vegetative phase but not at the reproductive phase. TVSu-9 with the highest number of fresh pods per plant, TVSu-513 with the highest weight of fresh pods per plant and TVSu-1659 could be further evaluated for stability in the characters before being introduced to farmers in Owerri, Southeastern Nigeria. Keywords: Bambara groundnut, evaluation, growth, reproductive characters, yield components INTRODUCTION Climate change has profound effect on tropical agriculture mainly through changes in rainfall and temperature. A mean temperature increase of C between two periods ( and ) indicated that Nigeria was experiencing global warming at a rate higher than the global mean temperature (Odjugo, 2011). As a result of a changing rainfall pattern (CGIAR, 1996; Odjugo, 2005; Odjugo, 2010; Obot et. al., 2010) delayed onset of rainfall is now being experienced across Nigeria (Anuforom, 2009). These changes in rainfall and temperature are mainly responsible for the occurrence of moisture stress in crop fields even in humid areas of Nigeria (Adejuwon, 2004). Moisture stress is the major abiotic stress factor limiting crop productivity worldwide (Sharp et. al., 2004; Barnabas et. al., 2008). Moisture deficits develop during periods when water loss in transpiration exceeds absorption or when water supply to the roots becomes difficult (Kramer, 1983; Anjum et. al., 2011). Moisture stress affects crops at different growth stages. In maize, moisture deficit imposed at different developmental stages reduced total biomass accumulation at silking by 37.0 %, at grain-filling period by 34.0 % and at maturity by 21.0 % (Kamara et. al., 2003). The overall effect is a reduction in yield. According to Munyiri et al. (2010), water stress in maize delayed silking by 3 days and increased anthesis-silking interval by 2 days with the resultant effect being yield reduction of between 17.0 and 81.0 %. To reduce the negative impacts of moisture stress resulting from climate change, it is necessary to apply adaptation strategies. The planting of drought tolerant crops in humid areas could be one such strategy. The crop is considered to be drought resistant (Tweneboah, 2000) and farmers claim that in years when groundnut (Arachis hypogea) production failed due to low rainfall, Bambara groundnut produced good returns (Linneman, 1990). Bambara groundnut is the only legume whose seeds are referred to and used as complete food because they contain protein, carbohydrate and fat in sufficient proportions to provide a nutritious food (Poulter and Caygill, 1980). The ripe seeds contain on average 10 % water, % protein, 4 9 % fat, % carbohydrate and 3 5 % fibre (Baudin and Mergeai, 2001). Unfortunately, reports on the evaluation of this crop in the rainforest zone of Nigeria are scanty irrespective of its agronomic and nutritional potentials. This field trial was therefore conducted to evaluate the performance of different accessions of Bambara groundnut with a view to identify those with promising growth characteristics under the humid environment of Owerri in Southeastern Nigeria. MATERIALS AND METHODS Location of experiment The experiment was conducted at the Teaching and Research Farm of the Federal University of Technology Owerri located on latitude North and longitude East with an elevation of 55.3m above sea level. Soils of the area are Ultisols, low in mineral reserve and fertility (Eshett, 1993). Some weather parameters (rainfall, temperature and relative humidity) for the study site were obtained from Imo State Agricultural Development Programme, Owerri. Soil sampling and physical and chemical analysis Random samples of soil from the experimental site were taken at a depth of 0-20 cm using a soil auger. The soil samples were bulked to form a composite sample, air dried and used to determine the physical and chemical properties of the soil. NJAFE VOL. 13 No. 4,

2 Treatments and experimental design The treatments comprised ten (10) Bambara groundnut accessions obtained from the International Institute of Tropical Agriculture (IITA) Ibadan, Nigeria. The treatments were arranged in a randomized complete block design with three (3) replications, giving 30 experimental plots (beds). Seed beds measuring 1.5 x 2.5 m were constructed in each experimental plot. Two seeds of Bambara groundnut were sown per hole at a spacing of 25 x 30 cm. This was later thinned to one plant per stand at 2 weeks after planting (WAP) to give a population of 1,333,333 plants ha -1 (50 plants plot -1 ). The plots were kept weed free throughout the period of experiment and no fertilizer was applied. Data collection The vegetative parameters measured at 50 % flowering were plant height, number of leaves, number of branches and dry matter (root and stem). The reproductive parameter were number of days to first flower, number of days to 50 % flowering, number of fresh pods and weight of fresh pods. Plant height was measured from ground level to the highest fully opened leaf. Number of leaves and branches were determined by physical count. To determine dry matter, plants were separated into root and shoot by cutting at ground level. The roots were dug out carefully with a ball of earth and washed to recover the roots. Both roots and shoots were then dried in the oven at 60 C to constant weight. The number of days to first flower was determined by counting the number of days from sowing to the appearance of first flower in each plot. Number of days to 50 % flowering was determined as number of days from sowing to the date which 50 % of the plants in each plot flowered. At harvest, pods from tagged plants in the central rows were counted and weighed. The mean number and weight of fresh pods were recorded as the number of fresh pods plant -1 and weight of fresh pods plant -1 respectively. Statistical analysis Analysis of variance (ANOVA) procedures described by Wahua (1999) were employed in analyzing the data while means were separated using the least significant difference (LSD) at 5 % level of probability. RESULTS Environmental conditions at the location of study The rainfall, temperature (minimum and maximum) and relative humidity of the study location from January to October are presented in Table 1. During the growing period (May - September), average monthly rainfall was mm while minimum and maximum temperatures were C and C respectively. Average monthly relative humidity was 78.4 %. Analysis of soil physical and chemical properties showed that the soil of the study site was acidic in reaction (ph=5.26) with a sandy loam texture (Table 2). Vegetative parameters of Bambara groundnut accessions The vegetative performances of the accessions are presented in Table 3. The accessions TVSu-513 and TVSu-690 had heights of 20.6 and 20.5 cm respectively, which were significantly higher than all other accessions. The shortest plant was TVSu-9 (15.7 cm). TVSu-1393 (19.2 cm) was significantly taller than TVSu-1397 (18.0 cm), TVSu-674 (17.9 cm), TVSu-1659 (17.3 cm) and TVSu-9 (15.7 cm), while TVSu-759 (19.0 cm) was significantly taller than TVSu-1659 (17.3 cm) and TVSu-9 (15.7 cm). Number of leaves of TVSu-1482 and TVSu-1393 were significantly higher than those of TVSu-9, TVSu-513, TVSU-690, TVSu-759 and TVSu-674. Similarly, TVSu- 1659, TVSu-751, TVSu-1397 and TVSu-9 were not significantly different in the number of leaves but produced significantly more leaves than TVSu-690, TVSu-759 and TVSu-674. The lowest number of leaves was produced by TVSu-674. Accession TVSu-690 had significantly greater root dry matter than TVSu-759, TVSu-1482, TVSu- 674 and TVSu-9 while TVSu-1393 produced significantly greater root dry matter than TVSu-1482, TVSu-674 and TVSu-9. The lowest root dry matter was produced by TVSu-9. Shoot dry matter contents in TVSu-1393 and TVSu-690 were significantly greater than all other accessions except TVSu-1397 and TVSu-751. Shoot dry matter was also significantly greater in TVSu-1397 than TVSu-9 and TVsu-674. Reproductive parameters of Bambara groundnut accessions The reproductive performances of the accessions are presented in Table 4. No significant differences (p<0.05) were observed among the accessions with respect to days to first flower, days to 50 % flowering, number of fresh pods and weight of fresh pods plant -1. On the average, the accessions produced their first flower in 33.0 days and attained 50 % flowering in 41.0 days. DISCUSSION The weather parameters (rainfall, temperature and relative humidity) at the location of study showed a favourable condition for growth of the crop. However, Bamishaiye et al. (2011) reported that too much rainfall at harvest may result in yield losses. Acid soil conditions in the location as indicated by the ph value and hydrogen/aluminum concentration could constitute a constraint to the growth of the crop. Maduako (1991) considered soil acidity as a major constraint to crop production in the tropics and particularly in the soils of Southeastern Nigeria. Wassermann et al. (1984) recommended the application of lime or other soil amendments for the growth and yield of Bambara groundnut. NJAFE VOL. 13 No. 4,

3 Table 1: Some weather parameters of the experimental site (January October, 2014) Month Rainfall (mm) Temperature ( 0 C) Maximum Minimum Relative humidity (%) January February March April May June July August September October Source: Imo State Agricultural Development Programme, Owerri Table 2: Physical and chemical properties of soil of the experimental site (0 20cm) Soil Properties Value Sand (%) Silt (%) 5.70 Clay (%) 4.90 Textural class Sandy Loam ph (H2O) 5.25 P (mg kg -1 ) N (%) Organic carbon (%) 0.85 Organic matter (%) 1.46 Cmol kg -1 Ca 2.15 Mg 0.95 K 0.03 Na 0.05 Al 0.27 H 0.85 ECEC 4.30 Table 3: Vegetative performances of Bambara groundnut accessions in Owerrri, Imo State Accessions Plant height (cm) No. of Leaves No. of Branches Root dry matter (g) Shoot dry matter (g) TVSu TVSu TVSu TVSu TVSu TVSu TVSu TVSu TVSu TVSu Mean LSD(0.05) Table 4: Reproductive performances of Bambara groundnut accessions in Owerri, Imo State Accessions DTFF DT50%F NFPPP WFPPP TVSu TVSu TVSu TVSu TVSu TVSu TVSu TVSu TVSu TVSu Mean LSD(0.05) ns ns ns ns DTFF=days to first flower; DT50%F=days to 50 % flowering; NFPPP=number of fresh pods plant -1 ; WFPPP=weight of fresh pods plant -1 The ten accessions Bambara groundnut showed variability in all the parameters studied. For example, TVSu-9 was ranked first for number of fresh pods per plant, 3 rd for days to first flower and days to 50 % flowering. Similarly, TVSu-513 was ranked first for weight of fresh pods per plant and plant height and 3 rd for root dry matter, while TVSu-1659 was ranked 2 nd in three reproductive characters, namely days to 50 % flowering, number of fresh pods per plant and 3 rd in number of leaves and number of branches per plant. The significant differences in vegetative growth parameters indicate variability among the accessions. Bambara groundnut shows a considerable amount of variability for various morphological, physiological and agronomic traits (Massawe et al., 2005). Tanimu and Aliyu (1990) reported a wide range of differences in the seed coat colour, seed sizes, pigmentation around the eye, pod shape, growth habit, yield, shelling percentage, days to 50 % NJAFE VOL. 13 No. 4,

4 flowering, days to maturity and other characters. This variability can be exploited for the production and improvement of the crop in the rainforest agroecology. The observed number of days to first flower agrees with the report by Bamishaiye et al. (2011) that Bambara groundnut starts flowering 30 55days after sowing. Poor yield in Bambara groundnut has been identified as a function of delayed flowering (Makanda et al., 2009). Hence accessions that flower early should be considered in the production of Bambara groundnut. CONCLUSION The findings from this study suggest that a great measure of variability exists among available Bambara groundnut accessions. Therefore introduction of this crop to the rainforest zone is possible when adequate screening of many genotypes has been done. TVSu-9 with the highest number of fresh pods per plant, TVSu-513 with the highest weight of fresh pods per plant and TVSu-1659 could be further evaluated for stability in the characters and introduced to farmers in Owerri, Imo State - Nigeria. REFERENCES Adejuwon, S. A Impacts of climate variability and climate change on crop yield in Nigeria. Lead paper presented at the Stakeholders Workshop on Assessment of Impact and Adaptation to Climate Change (AIACC), held at the Conference Centre Obafemi Awolowo University, Ile-Ife, September, Anjum S. A., Xie X. Y., Wang L.C., Saleem M. F., Man C. and Lei W Morphological physiological and Biochemical responses of plants to drought stress. African Journal of Agricultural Research, 6(9): Anuforom A. C Climate Change impacts in different agro-ecological zones of West Africa-Humid zone. Paper presented at the International Workshop on Adaptation to Climate Change in West African Agriculture at Quagadougou, Burkina Faso, April, Bamishaiye, O. M., Adegbola, J. A. and Bamishaiye, E. I Bambara groundnut: an underutilized nut in Africa. Advances in Agricultural Biotechnology, 1:60-72 Barnabas, B., Jager, K., and Feher, A The effect of drought and heat stress on reproductive process in cereals. Plants, Cell and Environment, 31: Baudoin, J. P. and Mergeai, G Grain legumes in crop production in tropical Africa, pp CGIAR Climate Change. Consultative Group on International Agricultural Research Newsletter, Vol. 3 No. 1. Eshett, E. T Wet land and Ecotones studies on land-water. National Institute of Ecology, New Delhi International Scientific Publication, New Delhi pp.1-7 Kamara, A. Y., Menkir, A., Badu-Apraku, B. and Ibikunle, O Reproductive and stay-green trait responses of maize hybrids improved open-pollinated varieties and farmer s local varieties to terminal drought stress. Maydica, 48: Kramer, P. J Water relations of plants. Academic Press, London. Linnemann, A. R Cultivation of Bambara groundnut (Vigna subterranea (L.) Verdc) in Western Province, Zambia: Report of a field study. Tropical Crops Communication, No. 16. Wageningen Agricultural University. Maduako, H. O Efficient fertilizer use for increased crop production: The humid Nigeria experience. Fertilizer Research, 29:65-79 Makanda, I., Tongoona, P., Madamba, R and Icishahayo, D. and Derera, J Path coefficient analysis Bambara groundnut pod yield components at four planting dates. Research Journal of Agricultural and Biological Sciences, 5(3): Massawe F. J., Mwale, S. S., Azam-Ali, S. N. and Roberts, J. A Breeding in Bambara groundnut (Vigna subterranea (L.) Verdc): Strategies considerations. Africa Journal of Biotechnology, 4(6): Munyiri S. W., Pathak R. S., Tabu I. M. and Gemenet D. C Effect of moisture stress at flowering on phenotypic characters of selected local maize landraces in Kenya. Journal of Animal and Plant Science, 8(1): Obot, N. I., Chendo, M. A. C., Udo, S. O. and Ewona I. O Evaluation of rainfall trends in Nigeria for 30years ( ). International Journal of the Physical Sciences, 5(14): Odjugo, P. A. O An analysis of rainfall patterns in Nigeria. Global Journal of Environmental Sciences, 4(2): Odjugo, P. A. O Regional evidence of climate change in Nigeria. Journal of Geography and Regional Planning, 3(6): Odjugo, P. A. O Climate change and global warming: the Nigerian perspective. Journal Sustainable Development and Environmental Protection, 1(1):6-17 NJAFE VOL. 13 No. 4,

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