Sarhad J. Agric. Vol. 26, No. 3, 2010 319 CHARACTER ASSOCIATION AND EVALUATION OF COWPEA GERMPLASM FOR GREEN FODDER AND GRAIN YIELD UNDER RAINFED CONDIANDNS OF ISLAMABAD M. IMRAN*, ASHIQ HUSSAIN*, SAJJAD HUSSAIN**, SARTAJ KHAN*, ALLAH BAKHSH*, M.S. ZAHID* and DOULAT BAIG * Fodder Research Programme, National Agricultural Research Centre, Islamabad Pakistan. ** Plant Genetic Resources Programme, National Agricultural Research Centre, Islamabad Pakistan. *** Oilseed Programme, National Agricultural Research Centre, Islamabad-Pakistan. ABSTRACT An experiment involving 14 local lines of cowpea germplasm including one promising line (P-518 as check) was conducted at Fodder Research Program, National Agricultural Research Centre, Islamabad during the summer of 2006. The main objective of this study was to assess the level of genetic variability exhibited by a germplasm collection of cowpea on morphological basis and to identify the lines suitable for fodder and grain yield. Data were collected on eight agro-morphological characters (tendril length, number of branches plant -1, number of leaves main branch -1, leaf area, pod length, number of seeds pod -1, green fodder and grain yields. Number of branches plant -1 showed a significant correlation (r =0.585) with leaf area but non-significant association with number of leaves per main branch and green fodder yield. Leaf area showed a negative and significant correlation (r =0.583) with pod length which is indicative of the fact that a plant having more vegetative growth (i.e., leaf area) produces small pods. It also showed a negative and non-significant association with number of seeds per pod and grain yield. In total two clusters were obtained in dendogram based on Ward s method. Out of the 14 lines studied three lines -CP/V4, CP/V2 and CP/V6 were found to be suitable for obtaining higher green fodder yield, whereas the lines CP/V10, CP/V5, No.1, SA-Dandy, CP/V2, CP/V6, CP/V3, CP/V7, CP/V8, CP/V11, CP/V9 and CP/V12 were found to be suitable for maximum grain yield. The data also suggested that two line CP/V2 and CP/V6 could be used both for fodder and grain yield, on the other hand line CP/V4 proved to be suitable exclusively for green fodder yield under rainfed conditions of Islamabad. Key words: Cowpea, yield components, fodder, grain, rained. Citation: Imran, M., A. Hussain, S. Hussain, S. Khan, A. Bakhsh,S. Zahid and D. Baig. 2010. Character association and evaluation of cowpea germplasm green fodder and grain yield under rainfed conditions of Islamabad. Sarhad J. Agric. 26 (3): 319-323 INTRODUCTION Cowpea (Vigna unguiculata L. Walp.) is an important leguminous crop and cultivated on 12.5 million hectares with an annual production of over three million metric tons worldwide (Quin, 1997). It is a crop of warm season, grown for grain, vegetable, and fodder purposes in moderately humid areas of tropics and sub tropics, although, some varieties show a considerable drought resistance (Muhammad et al. 1993). It cannot withstand frost and excessive heat reduces its growth as well (Bogdan, 1977). It can be grown in neutral to acidic soils but cannot tolerate alkalinity. The nutritional value of cowpea lies in its protein contents of 20-40%. It is a good source of quality protein, phosphorus, iron and vitamins. Cowpea young leaves, pods and peas contain vitamins and minerals, which have fuelled its usage for human consumption and animal feeding (Nielsen et al., 1997). Legume fodder is important for livestock production because it is rich in protein, minerals, phosphorus, calcium and vitamins (Rupela et al., 1997; Unkovich et al., 1997). Being a legume crop, it improves nitrogen status of the soil. Cowpea fodder is also a rich source of crude protein of 18.4% (Narayanan and Dabadghao (1972). Cowpea is a multipurpose crop for the production of fodder, hay, grain or green manure while providing the rotational benefits of legumes (Bull and Mayfield 1992). In Pakistan, cowpea is planted as spring or summer crop and about 20% it is consumed as vegetable. Many scientists across the world have studied genetic divergence of V. unguiculata. Kumawat and
M. Imran et al. Character association and evaluation of cowpea germplasm for green fodder 320 Raje (2005) evaluated 50 genotypes of cowpea for seed yield and its components and grouped the germplasm into 6 clusters. Seed yield per plant had the highest contribution towards the total genetic divergence; followed by seeds per pod, days to 50 % flowering, plant height and reproductive period. Khan et al. (2005) conducted a trial for screening high yielding cowpea varieties for fodder in the rainfed conditions of Kohat (Pakistan). Maximum green fodder yield was recorded for line P-518. This experiment was thus conducted to assess the level of genetic variability exhibited by a germplasm collection of cowpea on morphological basis and identify a set of the most suited lines both as fodder and grain crop for rainfed conditions of Islamabad area,. MATERIALS AND METHODS Thirteen lines of cowpea obtained from Barani Agricultural Research Institute (BARI) Chakwal were sown in augmented design on field area of Fodder Research Programme, NARC, Islamabad during the summer of 2006. Each line was grown in four rows each of six meter length. Row to row distance was maintained as 30 cm. Inter-line distances was maintained as one meter. A fertilizer dressing of 23-60 NP kg ha -1 was applied at the time of seed bed preparation. All other cultural practices including weeding, inter-culturing and pesticide application were kept uniform in all the plots. Cowpea line P-518 was used as check to estimate the degree of genetic variation among the lines studied. Data were recorded on quantitative traits including tendril length (cm), number of branches plant -1, number of leaves main branch -1, leaf area (cm 2 ), pod length (cm), number of seeds pod -1, green fodder yield (t h -1 ) and grain yield (t h -1 ) (Table-I) of three randomly selected plants from each line. However, green fodder and grain yield were recorded by harvesting two lines from each plot. Days to maturity were given a single value for each line. The collected data were statistically analysed using MS Excel 2000. Yield data of P-518 (check variety) was used for comparison to identify a set of lines with specificquantitative traits. Table I Quantitative traits recorded in the cowpea germplasm Quantitative trait Description of the traits TL (cm) Length of main branch from soil level to the tip of inflorescence B/P The branches whose origin is in the leaf axils in the main stem; mean of three randomly selected plants; Recoded at the time of harvesting L/B Mean of three randomly selected plants; counted at the time of harvest LA (cm 2 ) Mean of three randomly selected leaves; counted at the time of harvest PL (cm) Mean of three mature pods from three randomly selected plants S/P Mean of number of seeds per pod of three randomly selected plants GFY (t/ha) Mass of above-ground portion of the plants; measured per unit area basis and converted to t/ha Grn Y (t/ha) Dry seed weight of threshed plant material; measured per unit area basis and converted to t/ha RESULTS AND DISCUSSION Basic statistics for quantitative traits are presented in Table-II. High genetic variability was observed in green fodder yield, leaf area and tendril length whereas low to medium variability was observed in the rest of the traits studied. Tendril length ranged from 39.33 cm (CP/ V3) to 62.00 cm (CP/ V5). Tendril length of check variety was very close to the mean value (49.05 cm) for this trait. A bulk of six lines were in the range of 45.01-50.00 cm, followed by that of 35.01-40.00 cm. Some lines had the very short tendril length in this set of germplasm. High variation in tendril length may be attributed to its varietal characters (Table-IV). Table II Basic statistics of 14 lines along with check line (P-518) of Vigna unguiculata Traits Mean + SE SD Range Min. Max TL (cm) 49.05+1.88 7.05 39.33 62.00 B/P 6.29 + 0.25 0.94 5.00 7.67 L/B 12.50+ 0.74 2.76 8.33 18.00 LA (cm 2 ) 52.02+ 1.91 7.14 38.7 68.4 PL (cm) 15.75+ 0.45 1.67 13.17 19.33 S/P 13.02 + 0.57 2.15 9.33 16.67 GFY (t/ha) 84.52+ 7.51 28.09 33.33 116.67 Grn Y (t/ha) 1.21+ 0.13 0.48 0.3 2.1 SE=Standard error, SD=Standard deviation
Sarhad J. Agric. Vol. 26, No. 3, 2010 321 Table III Superior lines of Vigna unguiculata identified for specific traits Traits Check variety Identified genotypes TL (cm) 49.00 CP/V10, CP/V5, CP/V4, SA-Dandy, CP/V6, CP/V9 B/P 7.33 CP/V10, CP/V4 L/B 18.00 P-518 LA (cm 2 ) 49.03 CP/V10, CP/V4, No.1, CP/V2, CP/V6, CP/V3, CP/V7, CP/V8, CP/V11, CP/V12, PL (cm) 116.67 CP/V4, CP/V2, CP/V6 S/P 15.50 CP/V5, CP/V6, CP/V3, CP/V7, CP/V9, CP/V12 GFY (t/ha) 13.00 CP/V5, CP/V4, SA-Dandy, CP/V2, CP/V6, CP/V3, CP/V11, CP/V12 Grn Y (t/ha) 0.80 CP/V10, CP/V5, No.1, SA-Dandy, CP/V2, CP/V6, CP/V3, CP/V7, CP/V8, CP/V11, CP/V9, P/V12 Number of branches per plant ranged from 5.00 (S-A Dandy) to 7.67 (CP/ V10 and CP/ V4). Most of the accessions (8) were in the range of 5.01-6.00 as compared to those in the check variety, in which case the value fell closer to the mean value (6.29) for this trait (Table-IV). Number of leaves per main branch ranged from 8.33 (CP/ V4) to 18.00 (P-518) with an average of 12.50 with the most (6) lying in the range of 10.01 to 12.00 (Table-IV). The exceedingly high value of this trait for the check variety (18.00) when compared to other lines proves its superiority over the existing cowpea cultivars. Leaf area (length x breadth in cm 2 ) showed an incredibly high variation ranging from 38.70 (CP/ V5) to 68.40 cm 2 (CP/ V 10) with an average value of 52.02 cm 2 (Table-IV). Most of the lines (6) were in range of 50.01-55.00 cm 2 followed by three lines falling in the range of 55.01 to 60.00 cm 2 (Table IV). Table IV Varieties Average yield and yield components of cowpea under test TL B/P L/B 1 LA GFY (cm) (cm 2 ) (t ha -1 ) PL (cm) S/P Grn Y (t ha -1 ) CP/ V10 50.00 7.67 12.00 68.40 66.67 13.17 10.00 1.50 CP/ V5 62.00 5.33 14.67 38.70 33.33 19.33 14.67 1.90 CP/ V4 56.33 7.67 8.33 53.50 116.67 15.00 13.67 0.30 S-A Dandy 49.67 5.00 9.00 45.77 83.33 13.83 14.00 0.80 No. 1 48.67 6.00 11.00 51.27 100.00 14.67 12.67 1.40 CP/ V2 39.67 6.00 11.00 52.47 116.67 15.33 13.33 1.10 CP/ V6 59.00 6.67 10.00 50.40 116.67 16.50 15.00 2.10 CP/ V3 39.33 5.00 12.00 51.00 50.00 17.33 14.00 1.50 CP/ V7 39.67 6.00 11.00 52.03 50.00 16.83 9.33 1.00 CP/ V8 45.00 7.00 14.00 57.60 100.00 15.00 10.00 1.40 CP/ V11 46.00 5.33 13.33 55.47 83.33 13.97 14.67 0.90 CP/ V9 54.33 6.00 14.33 43.60 66.67 16.90 11.33 1.40 CP/ V12 48.00 7.00 16.33 59.00 83.33 17.17 16.67 0.90 P-518 (Check) 49.00 7.33 18.00 49.03 116.67 15.50 13.00 0.80 SE 1.88 0.25 0.74 1.91 7.51 0.45 0.57 0.13 TL, B/P, L/B, LA, GFY, PL, S/P and Grn Y denote tendril length, branch -1, leaves branch -1, leaf area, green fodder yield, pod length, seeds pod -1 and grain yield, respectively. Green fodder yield is an important trait which is attributed to the tendril length, number of branches per plant, number of leaves per branch and leaf area. Green fodder yield also showed very high variation ranging from 33.33 (CP/ V5) to 116.67 t ha -1 (CP/ V4, CP/ V2, CP/ V6, and P-518) t ha -1 with an average of 84.52 t ha -1 (Tabl e-iv). Pod length ranged from 13.17 (CP/ V 10) to 19.33 cm (CP/V5) with an average value of 15.75 cm. Most of the lines were in the range of 14.01to-18.00 cm. Here, again, the check variety fell very close to the mean value for this trait (Table IV). Number of seeds per pod ranged from 9.33 (CP/ V7) to 16.67 (CP/ V 12) with an average of 13.02. Most of the lines (6) fell in the range of 12.01 to 14.00. Grain yield ranged from 0.3 (CP/ V4) to 2.1 t ha -1 (CP/ V6) with an average of 1.21 t ha -1. Most of the lines (6) were in the range of 1.01-1.50 t ha -1. Comparing green fodder yield and grain yield data of all the lines studied,one can easily identify the lines that transfer more photosynthesis to their reproductive part (seed) than from those the lines with higher proportionate from their biomass to vegetative part ( fodder). Four lines CP/ V10, P/ V5, CP/ V3 and CP/ V9 correspond to the earlier group whereas three lines/varieties CP/ V4, CP/ V2 and P-518 correspond to the later group (Table-IV). These results are in agreement with that of Kumawat and Raje
M. Imran et al. Character association and evaluation of cowpea germplasm for green fodder 322 (2005) and Khan et al. (2005).Similarly index was determined by generating a dandogram by Ward s method. The Fig. 1 shows a total of two clusters based on morphological data. Cluster I consists of six genotypes while cluster II consists of eight lines. Data for quantitative and qualitative parameters of cowpea varieties are given in Tale- IV. Tendril length, number of branches, number of leaves main branch -1, green fodder yield, number of seeds per pod, and grain yield showed non-significant differences among various varieties of cowpea. Cowpea variety CP/ V5 produced plants of maximum tendril length (62.00 cm). Significantly lowest tendril length (39.33 cm) was recorded in variety CP/ V3. Regarding number of branches plant -1, it was observed that cowpea varieties CP/ V4 and CP/ V10 recorded higher and with value of 7.67. Cowpea varieties CP/V3 and S-A Dandy produced the lowest with value of 5.00. The highest number of leaves per main branch (18.00) were observed in variety P-518 and the lowest (9.00) in accession S-A Dandy. With regards to leaf area, variety CP/ V10 had the highest (68.40 cm 2 ). However, the lowest leaf area (38.70 cm 2 ) was recorded in variety CP/ V5. As far as green fodder yield is concerned, varieties CP/ V2, CP/ V4, CP/ V6, and P- 518 produced the highest and similar green fodder yields. The highest pod length (19.33 cm) was recorded in accession CP/ V5 while the lowest (13.17 cm) in cultivar CP/ V10. Accession CP/ V12 produced the highest number of seeds per pod (16.67) whereas the lowest and similar (10.00) in lines CP/ V8 and CP/ V10. The highest grain yield (2.1 t ha - 1 ) was obtained from line CP/ V6 while the lowest (0.3 t ha -1 ) in accession CP/ V4. Table-V revealed that a total of twenty eight values for coefficient of correlation ( r ) among traits under study were obtained. Out of which 'r" values for leaf area vs. branches plant -1 and green fodder yield vs. branches plant -1 were positively significant. Number of branches per plant showed a positive and significant correlation (r =0.585) with leaf area and green fodder yield (5.03) whereas positive non-significant association with number of leaves per main branch and green fodder yield was observed. Leaf area showed a negative and significant correlation (r =0.583) with pod length which is indicative of the fact that a plant with more vegetative growth (i.e., leaf area) produces small pods. It also showed a negative and non-significant association with number of seeds per pod and grain yield. Green fodder yield showed a negative and non-significant correlation with pod length and grain yield. However, pod length showed a positive and non-significant association with number of seeds per pod and grain yield. Table V Correlation coefficients among different morphological traits for cowpea accessions Traits TL (cm) B/P L/B LA (cm 2 ) GFY (t/ha) PL (cm) S/P B/P 0.205 L/B 0.002 0.153 LA (cm 2 ) -0.374 0.585* -0.040 GFY 0.028 0.503* -0.152 0.214 PL (cm) 0.239-0.273 0.340-0.583* -0.485 S/P 0.306-0.236 0.087-0.260 0.162 0.282 Grn Y 0.293-0.215 0.078-0.174-0.327 0.407-0.041 TL, B/P, L/B, LA, GFY, PL and S/P denote tendril length, number of branches plant -1, number of leaves main branch -1, leaf area, green fodder yield, pod length, number of seeds pod -1 and grain yield, respectively. Fig. 1 Tree diagram for 14 lines of cowpea Ward s method Euclidean distances (both on green fodder and grain yields)
Sarhad J. Agric. Vol. 26, No. 3, 2010 323 CONCLUSION Pakistan is endowed with a rich floristic diversity in grain legumes in which cowpea enjoys a remarkable importance. Being drought tolerant crop it can be grown on a wide area of marginal lands of Sindh, NWFP and Punjab provinces. Out of the fourteen lines under study CP/V4, CP/V2 and CP/V6 were found suitable for getting higher green fodder yield whereas the lines CP/V10, CP/V5, No.1, SA-Dandy, CP/V2, CP/V6, CP/V3, CP/V7, CP/V8, CP/V11, CP/V9 and CP/V12 were found more suitable for maximum grain yield. CP/V2 and CP/V6 may be used both as fodder and grain crop whereas CP/V4 seems to be suitable exclusively as green fodder yield. REFERENCES Bogdan, A.V. 1977. Tropical pastures and fodder plants (grasses and legumes) published in USA by Longman Inc., New York. pp. 423-426. Bull, B. and A. Mayfield. 1992. Growing Vetch. (Bold images; Cowandilla, S. Aust.). Khan, M., M. Niaz, A. Naveed, K. Azim and J. Iqbal. 2005. Evaluation of high yielding cowpea varieties for green fodder yield under rainfed conditions of NWFP. Indus J. Plant Sci. 4 (4): 576-578. Kumawat K.C. and R.S. Raje. 2005. Genetic divergence in cowpea (Vigna unguiculat L. Walp.) Arid Legumes for Sust. Agric. and Trade. 1: 25-27. Muhammad, D., A. Hussain, S. Khan and M.B. Bhatti. 1993. Variability for green fodder yield and quality in cowpea under rainfed conditions. Pakistan Agric. Res. 14 (2, 3): 154-158. Narayanakutty, C., C.K. Dunanda and U. Jaikumaran. 2005. Genetic divergence in pole type vegetable cowpea. Indian J. Hort. 62 (4): 354-357. Narayanan, T.R. and P.M. Dabadghao. 1972. Forage Crops of India. Indian Council of Agric. Res. New Delhi. pp.243-247. Nielsen, S., T. Ohler and C. Mitchell. 1997. Cowpea leaves for human consumption: production, utilization, and nutrient composition. In: Singh, B., D.R. Mohan Raj, K. Dashiell, L. Jackai (eds) Advances in Cowpea Res. Int. Instt. of Trop. Agric. (IITA) and Japan Int l. Res. Center for Agric. Sci. (JIRCAS), Ibadan, Nigeria. pp. 326-332. Quin, F.M. 1997. Introduction. p. ix xv. In: Singh, B.B., D.R. Mohan Raj, I.E. Dashiell and L.E.N. Jackai (eds.), Advances in Cowpea Res. Co-publication of Int. Instt of Trop. Agric. (IITA) and Japan Int l. Res. Center for Agric. Sci. (JIRCAS), IITA, Ibadan, Nigeria. Rupela, O.P., C. Johnsen and D.F. Herridge. 1997. Extending nitrogen fixation in farmer s fields. Int l. Crop Res. Instt. in Semi-Arid Tropics, Patancheru 502 324 Andhra Pradesh, India. Unkovich, M.J., J.S. Pate and P. Sanford. 1997. Nitrogen fixation in Australian Mediterranean agriculture. Aust. J. Agric. Res. 48: 267-293.