Md.Harun-or -Rashied,Md.Nurul Huda Al Mamun,A.B.M.Sahidul Islam,M.Mizanur Rahman,N.M.Jahangir
Soil Resource Development Institute, Bangladesh
ABSTRACT
The experiment was conducted at the Horticulture Farm, Bangladesh Agricultural University, Mymensingh during the period from December 2001 to May 2002 to study on the performance of variety and planting materials the growth and yield of sweet potato. There were five sweet potato varieties viz., Tripti, Kamalasunduri, Daulatpuri, BARI sweet potato-4 and BARI sweet potato-5 and three cuttings of vine viz., tip, middle and basal portion used as planting materials. There were wide variations among the varieties in most of the parameters studied. BARI sweet potato-5 produced longest vine and maximum tuberous root per plant while Tripti produced maximum number of branches per plant and Daulatpuri gave longest tuberous roots. Tip cuttings performed best in survivability, vine length, number of branches and tuberous roots per plant.
Key word: Planting materials, Variety, Growth and yield
1. INTRODUCTION
Sweet potato (Ipomoea batatas Poir) is one of the major starch rich root crops of the tropics and sub-tropics belonging to the family Convolvulaceae. It is very popular among the poor people of Bangladesh because of its low price. The tuberous roots of this crop are edible and are consumed as boiled, baked, roasted or fried forms (Onwueme, 1978). The young vine with tender leaves is also consumed as vegetable. Bangladesh produced 378 thousand metric tones of sweet potato in an area of 4089 thousand hectares of land showing an average yield of 9029 metric tones per hectare during the year 1999-2000 (BBS, 2001). The average yield is very low compared to Japan and Korea where per hectare yields are reported to be 22.7 and 21.0 t/ha respectively (FAO, 1999). The main reasons for such lower yield are mainly use of low yielding varieties and sub-optimal production practices. Only five improved varieties, namely, Tripti, Kamalasunduri, Daulatpuri, BARI sweet potato-4 and BARI sweet potato-5, have been developed by Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur (Razzaque et al. 2000). These varieties are yet to be popularized among the farmers. Sweet potatoes are propagated normally by vine cuttings. The farmers in our country generally use cut pieces of vines irrespective of the position (basal, middle or apical part of vines). It is reported some advantages of apical cutting over the use of other parts of vine in producing higher yield (Hossain and Mondal, 1994), but this is not well accepted and even not extensively practiced in sweet potato cultivation. Moreover, influence of different vine parts of different varieties were also not evaluated properly. The present work was, therefore, undertaken to find out suitable vine parts as planting material of different varieties for maximization of vegetative growth as well as yield of sweet potato.
2. MATERIALS AND METHODS
The field experiment was carried out at the Horticulture Farm of Bangladesh Agricultural University, Mymensingh during the period from December, 2001 to May, 2002 to study the performance of variety and planting materials on growth, yield and physiological attributes of sweet potato. The experimental site was located at 24.60 N latitude and 90.50 E longitudes. The soil of the experimental plot was sandy-loam in texture belonging to the Old Brahmaputra Flood Plain under the Agro-Ecological Zone 9 having non calcareous dark gray flood plain soil (FAO, 1988). The land was medium high with adequate irrigation and drainage facilities. Soil characteristics of the experimental site at a depth 0-30 cm were assessed at the “Humboldt Soil Testing Laboratory”, Department of Soil Science, Bangladesh Agricultural University, Mymensingh.. The soil characteristics were as follows: Soil pH 6.37, Organic carbon (%)0.61, Organic matter (%)1.05, Total nitrogen (%) 0.06, Available phosphorus (ppm)25.00, Available sulphur (ppm) 6.00 and Exchangeable K (meq/100 g soil) 0.07. The whole vines of these five varieties were collected from the Tuber Crops Research Centre (TCRC), Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur. Vine cuttings of sweet potato (tip, middle and basal portion) approximately 30 cm in length with at least 6-7 nodes were used. The experiment consisted two factors namely, varieties and vine cuttings which were as follows.
Factor A: It included five varieties of sweet potato such as: V1- Tripti V2-Kamalasunduri V3- Daulatpuri V4-BARI sweet potato-4 V5-BARI sweet potato-5
Factor B: Three types of vine cutting like P1-Tip cutting,P2- Middle portion vine cutting , P3- Basal portion were used as planting material . The two factor experiment was laid out in the Randomized Complete Block Design (RCBD) with three replications. The plants were spaced with 60 × 30 cm spacing (Rashid and Mannan, 1986) in unit plots of 2.4m×2.4m. The land was fertilized with well decomposed Cow dung 10 tons/ha, Urea 150 kg/ha, Triple Super Phosphate (TSP) 125 kg/ha and Murate of Potash (MP) 175 kg/ha. The entire amount of cow dung, TSP, one-fourth of urea and MP were applied to each experimental plot during final land preparation. Rest part of urea and MP were side dressed after 60 days of planting. The vine cuttings were planted in the experimental plots in the afternoon of 1 December, 2001.The intercultural operation like weeding, earthing up, irrigation, and Vine lifting and plant protection from pest were done whenever needed. Data were collected on different growth and physiological parameters of sweet potato. The plant of the outer two rows and the extreme ends of the middle rows were excluded from random selection of plant to avoid the border effects. Ten plants were randomly selected from each plot to record data on cutting survivability (%), length of vine (cm), number of branches per plant, number of tuberous roots per plant, length of tuberous roots, diameter of tuberous roots, regularity in shape and grading of tuberous roots by number.The data were analyzed to find out the significance of the difference among the treatments. The analysis was performed by F-test and the significance of the difference between pairs of treatment mean was evaluated by the Least Significant Difference (LSD) test, at 1% and 5% level of probability (Gomez and Gomez, 1984).
3. RESULTS AND DISCUSSION
3.1. Cutting survivability (%)
There was significant variation among the varieties in respect of cutting survivability recorded at 40 DAP. The highest survivability of cutting (92.97%) was found in the variety BARI sweet potato-5 followed by Daulatpuri (90.04%), Tripti (89.24%) and Kamalasunduri (84.72%) (Fig.1). It was lowest in BARI sweet potato-4 (Fig. 1). Survivability of sweet potato cutting was also affected by different types of cutting. The highest survivability of cutting (94.38%) was observed with tip cuttings followed by middle cuttings (90.43%) and the lowest survivability (77.71%) was found in basal cuttings (Table 6). The combined effect was significant .The highest percentage of cutting survivability (95.83%) was observed in the treatment combination of Tripti with tip cuttings and as well as in the treatment combination of Daulatpuri with tip cuttings (Table 7). The lowest percentage of cutting survivability (69.79%) was observed in the variety of Kamalasunduri when basal portion was used as vine cutting and also in variety BARI sweet potato-4 when basal cutting was used. The survivability of cuttings was higher in tip and middle cuttings in comparison with basal cuttings. High mortality rate incase of basal cuttings was perhaps due to over maturity of tissue, absence of leaves and number of leaf buds from where endogenous hormone was supposed to form and help in the initiation of roots. Shanmugavelu et al. (1972) reported poor establishment of cuttings when leaves were removed before planting.
3.2. Length of vine (cm)
There was a significant difference in vine length among the varieties recorded at 45, 60, 75, 90, 105, 120 DAP and at harvest. At harvest, the variety BARI sweet potato-5 produced longest (207.66 cm) vine followed by Kamalasunduri (182.21 cm), Tripti (177.52 cm) and BARI sweet potato-4 (160.90 cm). Where as, the shortest (96.86 cm) vine length was recorded in Daulatpuri (Fig. 2).The length of the vine per plant was significantly influenced by vine parts .At harvest, tip cuttings produced the highest length of vine (173.73 cm) (Table 6). The shortest length of vine was produced by basal cuttings (158.30 cm)(Table 6).The length of the longest vine was found significantly different due to the combined effect of varieties and vine parts at different days after planting .At harvest, the length of the longest vine (216.00 cm) was found in the treatment combination of variety BARI sweet potato-5 with middle portion vine cuttings and the shortest length of the vine (92.43 cm) was found in the treatment combination of variety Daulatpuri with basal cuttings (Table 7). There was also significant interaction between different varieties and vine parts at harvest in this respect. Tip cuttings produced maximum length of vine might be due to early survivability and high vigor of tip cuttings for subsequent growth of vine.
3.3. Number of branches per plant
At harvest, number of branches per plant ranged from 14.93 to 18.81 (Fig. 3) among different varieties. The maximum number of branches per plant was produced by the variety Tripti and it was minimum Kamalasunduri (14.93). Rests of the three varieties were statistically similar in this respect. Differences in branching might be due to genotypic variation. The number of branches per plant differed significantly by different types of cutting (Fig.3) .At harvest, the highest number of branches (19.71) per plant was found in tip cuttings and the lowest number of branches (15.77) was found in basal cuttings (Table 6). The interaction effect between variety and vine parts was found to be significant in respect of number of branches per plant at harvest. The highest (23.92) number of branches was obtained from the treatment combination of Tripti with tip cutting and lowest (14.27) from BARI sweet potato-5 with basal cutting (Table 7).
The plants from tip cuttings gave more branches because of the fact that tip cuttings established quickly in the soil by initiating more roots and thereby encouraged subsequent production of more branches. This finding agrees with the results of Chowdhury et al. (1986).
3.4. Number of tuberous roots per plant
There was significant variation among the varieties in respect of number of tuberous roots per plant (Table 1). The highest number of tuberous roots per plant (4.54) was found in the variety BARI sweet potato-5 followed by the variety of Kamalasunduri (3.92), BARI sweet potato-4 (3.89) and Tripti (3.73).The lowest number of tuberous roots per plant (3.42) was obtained from variety Daulatpuri. Siddique (1985) found that the number of tuberous root per plant varied from 1.78 to 6.03. The number of tuberous roots per plant was significantly influenced by vine parts (Table 2). The highest number of tuberous roots per plant (4.52) was obtained from tip cuttings which was statistically different from others. The minimum number of tuberous roots (3.41) was produced by the basal cuttings which differed statistically from middle cuttings (3.78). Bhuiyan and Chowdhury (1984) found that tip cuttings produced greater number of tuberous roots than other two types of cutting. The interaction between variety and vine part was significant and their combined effect was also significant in respect of number of tuberous root (Table 3). The highest number of tuberous roots per plant (5.27) was found in the treatment combination of BARI sweet potato-5 with tip cuttings and lowest (3.03) from Daulatpuri with basal cuttings.
3.5. Length of tuberous roots
A wide variation was observed in length of tuberous root among the varieties (Table 1). The variety Daulatpuri produced maximum (13.93 cm) length of tuberous roots and Tripti produced minimum (10.28 cm) length of tuberous roots which was statistically similar with the variety BARI sweet potato-5 (10.54 cm). The variety Kamalasunduri produced length of tuberous root 11.24 cm which was statistically similar with BARI sweet potato-4 (11.66 cm). Hafizuddin and Haque (1979) reported that length of tuberous roots varied from variety to variety. The effect of vine parts on length of tuberous root was significant (Table 2). The maximum length of tuberous roots (12.48 cm) was found from tip cuttings and lowest (10.60 cm) from basal cuttings. The combined effect of different variety and vine parts in respect of length of tuberous root showed significant variation (Table 3). The maximum length of tuberous roots (15.60 cm) was found in the treatment combination of variety Daulatpuri with tip cuttings.
3.6. Diameter of tuberous roots
The diameter of tuberous roots varied markedly among the varieties (Table 1). The highest diameter of tuberous roots (4.92 cm) was found in variety Kamalasunduri that was statistically similar to the diameter of tuberous roots of Tripti (4.84 cm) and BARI sweet potato-4 (4.68 cm). This might be due to the varietal characteristics. The diameter of tuberous root significantly influenced by vine parts (Table 2). The maximum diameter of tuberous roots (4.94 cm) was recorded from tip cuttings followed by middle cuttings (4.49 cm) and the basal cuttings (3.98 cm). The combined effect of different variety and vine parts was found significant on the diameter of tuberous roots (Table 3). The largest diameter of tuberous root (5.70 cm) was obtained from variety Tripti with tip cuttings and the minimum (3.45 cm) was obtained from Daulatpuri with basal cuttings which was statistically similar to the same variety with middle cuttings (3.53 cm).
3.7. Regularity in shape of tuberous root
Regularity in shape exhibited significant variation on different varieties (Table 1). The score of regularity in shape of tuberous root as influenced by variety ranged from 2.93 to 6.57. The highest score (6.57) was obtained from BARI sweet potato-5 followed by BARI sweet potato-4 (5.57), Kamalasunduri (4.40) and Daulatpuri (3.40). The lowest score (2.93) was found in the variety Tripti. Vine cuttings also had significant effect on regularity in shape of tuberous root (Table 2). Maximum regular tuber was found with tip cuttings scored highest (5.26), while the lowest score (3.88) was found in basal cuttings. There was significant interaction between type of cutting and varieties on the production of regular shape of tuberous roots. The highest score for regular shape of tuberous root (7.5) was obtained from BARI sweet potato-5 with middle cuttings which was statistically similar with tip cuttings (7.00) of same variety (Table 3).
3.8. Grading of tuberous roots by number
There was a significant difference in distribution of tuberous root sizes among the varieties (Table 4). The highest percentage (25.55) of large (>200 g) tuberous roots was found in the variety Tripti, which was statistically similar with Kamalasunduri (25.06%) and BARI sweet potato-5 (23.90%). The variety Kamlasundari produced the highest percentage (45.04%) of medium tuberous root (100 to 200 g) and the lowest (38.92%) was found in the variety Daulatpuri. In case of small (<100 g) tuberous root, the highest percentage (41.15%) was found in the variety Daulatpuri followed by BARI sweet potato-4 (37.27%), BARI sweet potato-5 (37.20%) and Tripti (33.18%). Vine cuttings also showed significant variation on grading of tubers (Table 5). The highest percentage (26.99%) of large tuberous roots was found in tip cuttings followed by middle cuttings (23.36%) and basal cuttings (20.05%). In case of medium (100-200 g) tuberous root, the highest percentage (41.16%) was found from basal cuttings and lowest (40.71%) from tip cuttings. The highest percentage (39.08%) of small tuberous roots was obtained from basal cuttings which differed statistically from tip and middle cuttings.
4. Conclusion: There were wide variations among the varieties in most of the characters studied. None of the varieties was found best in all parameters. Tip cuttings performed best in all cases of the study.
References:
BARI. 1998. Sweet Potato (Leaflet in Bengali). Tuber Crops Research Centre, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur.
BBS. 2001. Monthly Statistical Bulletin of Bangladesh, May 2001. Bangladesh Bureau of Statistics. Statistics Division, Ministry of Planning, Govt. of the Peoples Republic of Bangladesh, Dhaka. p. 55.
Bhuiyan, M.A.J. and A.R. Chowdhury. 1984. Effect of methods of planting and types of cutting on the growth and yield of sweet potato. Bangladesh J. Agril. Res., 9(1): 27-32.
Chowdhury, S.H., S.U. Ahmed and A.F.M. Sharfuddin. 1986. Effect of number of nodes in different types of vine
cutting on the growth and yield of swees potato. Bangladesh Hort. 14(1): 29-33.
FAO. 1988. FAO Production Year Book. Basic Data Unit. Statistics Division, Food and Agricultural Organization of the United Nations, Rome, Italy, 48:90.
FAO. 1999. FAO Production Year Book. Basic Data Unit. Statistics Division, Food and Agricultural Organization of the United Nations, Rome, Italy, 53:95.
Gomez, K.A. and A.A. Gomez. 1984. Statistical Procedure for Agricultural Research (2nd ed.). John Wiley & sons, Singapore. pp. 18-192.
Hafizuddin, M. and M.A. Haque. 1979. Effect of nitrogen and potash at different levels on the yield of two local varieties of sweet potato. Bangladesh Hort. 7(1&2) : 18-23.
Hossain, M.M. and M.A.A. Mondal. 1994. Effects of vine parts on the growth and yield of three sweet potato varieties. Bangladesh J. Sci. and Ind. Res. 29(3): 181-184.
Onwueme, I.C. 1978. The Tropical Tuber Crops: Yams, Cassava, Sweet potato and Cocoyams. English Language Book Society and John Wiley & Sons, Chichester. p. 179.
Rashid, M.M. and M.A. Mannan. 1986. Mitha Alur Chash (in Bengali). Root Crop Project, Bangladesh Agril. Res. Inst., Joydebpur, Gazipur. pp. 5-10.
Razzaque, M. A., M.A. Sattar, M.S. Amin, M.A. Quiyum and M.S. Alam. 2000. Krishi Projukti Hatboi (Handbook on Agro-technology). (2nd ed.). Bangladesh Agricultural Research Institute, Gazipur 1701, Bangladesh. pp. 211-222.
Shanmugavelu, K.G., S. Thamburaj and A. Shanmugan. 1972. Studies on the effect of time of planting and type of planting materials on the yield of sweet potato. South Indian Hort., 20(1/14): 55-58.
Siddique, M.A.R. 1985. Studies on the morphology, growth and yield of some sweet potato genotypes. M.Sc.(Ag.) thesis, Dept. of Hort., Bangladesh Agril. Univ., Mymensingh.
Table 1. Main effect of variety on the growth and yield contributing characters of sweet potato
Variety Number of tuberous roots/plant Length of tuberous roots (cm) Diameter of tuberous roots (cm) Regularity in shape of tuberous roots (score)
V1 3.73 10.28 4.84 2.93
V2 3.92 11.24 4.92 4.40
V3 3.42 13.93 3.81 3.40
V4 3.89 11.66 4.68 5.57
V5 4.54 10.54 4.09 6.57
LSD (0.05) 0.354 0.605 0.423 0.372
LSD (0.01) 0.477 0.817 0.571 0.501
V1 : Tripti V2 : Kamalasunduri V3 : Daulatpuri V4 : BARI Sweet Potato – 4 V5 : BARI Sweet Potato – 5
Table 2. Main effect of vine parts on the growth and yield contributing characters of sweet potato
Vine parts Number of tuberous roots/plant Length of tuberous roots (cm) Diameter of tuberous roots (cm) Regularity in shape of tuberous roots (score)
P1 4.52 12.48 4.94 5.26
P2 3.78 11.51 4.49 4.58
P3 3.41 10.60 3.98 3.88
LSD (0.01) 0.369 0.369 0.442 0.388
P1 : Tip cutting P2 : Middle portion vine cutting P3 : Basal portion vine cutting
Table 3. Combined effect of variety and vine parts on the growth and yield contributing characters of sweet potato
Treatment combination Number of tuberous roots/plant Length of tuberous roots (cm) Diameter of tuberous roots (cm) Regularity in shape of tuberous roots (score)
V1P1 4.67 11.24 5.70 3.60
V1P2 3.53 9.42 4.80 3.00
V1P3 3.20 10.17 4.03 2.20
V2P1 4.30 11.79 5.10 5.50
V2P2 3.70 11.92 5.53 4.20
V2P3 3.43 9.99 4.13 3.50
V3P1 3.83 15.60 4.43 4.00
V3P2 3.40 12.59 3.53 3.20
V3P3 3.03 13.60 3.45 3.00
V4P1 4.73 12.29 5.13 6.20
V4P2 3.63 13.21 4.17 5.00
V4P3 3.30 9.47 4.73 5.50
V5P1 5.27 11.48 4.33 7.00
V5P2 4.63 10.39 4.40 7.50
V5P3 3.73 9.75 3.53 5.20
LSD (0.01) 0.826 1.414 0.989 0.868
CV (%) 9.40 5.44 9.82 8.41
V1 : Tripti V2 : Kamalasunduri V3 : Daulatpuri V4 : BARI Sweet Potato – 4 V5 : BARI Sweet Potato - 5
P1 : Tip cutting P2 : Middle portion vine cutting P3 : Basal portion vine cutting
Table 4. Main effect of variety on grading of tuberous root by number and by weight
Variety Grading of tuberous roots (%)
> 200 g 100-200g <100g
V1 25.55 41.26 33.18
V2 25.06 45.04 30.24
V3 20.18 38.92 41.15
V4 22.64 39.87 37.27
V5 23.90 39.81 37.20
LSD (0.01) 2.213 2.798 2.534
V1 : TriptiV2 : KamalasunduriV3 : DaulatpuriV4 : BARI Sweet Potato – 4 V5 : BARI Sweet Potato – 5
Table 5. Main effect of vine cuttings grading of tuberous roots by number.
Vine parts Grading of tuberous roots (%)
>200 g 100-200 g <100 g
P1 26.99 40.71 32.34
P2 23.36 41.08 36.01
P3 20.05 41.16 39.08
LSD (0.05) 1.270 -- 1.455
LSD (0.01) 1.714 -- 1.963
P1 : Tip cutting P2 : Middle portion vine cutting P3 : Basal portion vine cutting
Table 6. Main effect of vine parts on the cutting survivability (%), length of vine (cm) and
number of branches of sweet potato
Vine parts Cutting survivability at 40 DAP(%) Length of vine At harvest (cm) Number of branches per plant At harvest
P1 94.38 173.73 19.71
P2 90.43 163.01 17.41
P3 77.71 158.30 15.77
LSD (0.05) 3.408 2.623 0.867
LSD (0.01) 4.597 3.539 1.170
P1 : Tip cutting P2 : Middle portion vine cutting P3 : Basal portion vine cutting
Table 7. Combined effect of variety and vine cuttings on the cutting survivability (%), length of vine (cm)
and number of branches of sweet potato
Treatment combination Cutting survivability at 40 DAP (%) Length of vine (cm)
at harvest Number of branches
at harvest
V1P1 95.83 189.80 23.92
V1P2 92.71 172.40 19.80
V1P3 79.17 170.37 15.95
V2P1 94.79 207.70 14.67
V2P2 89.58 171.27 15.00
V2P3 69.79 167.67 15.84
V3P1 95.83 95.03 21.67
V3P2 93.83 103.10 17.73
V3P3 80.46 92.43 14.83
V4P1 90.63 171.47 18.62
V4P2 81.25 152.30 16.37
V4P3 69.79 158.93 16.50
V5P1 94.79 204.63 18.17
V5P2 94.79 216.00 19.16
V5P3 89.33 202.33 14.27
LSD (0.05) 7.62 6.217 1.939
LSD (0.01) 10.28 8.387 2.616
CV (%) 5.21 2.13 6.83
V1 : TriptiV2 : KamalasunduriV3 : DaulatpuriV4 : BARI Sweet Potato – 4 V5 : BARI Sweet Potato - 5
P1 : Tip cutting P2 : Middle portion vine cutting P3 : Basal portion vine cutting
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