Regional Wheat Research Institute, Shyampur, Rajshahi, Bangladesh. 3. Abstract: The research work was carried out with twenty wheat varieties/lines to study ...
Journal of Applied Sciences Research, 4(3): 258-261, 2008 © 2008, INSInet Publication
Effect of Source and/or Sink Restriction on the Grain Yield in Wheat 1
M.S. Alam, 2A.H.M.M. Rahman, 1M.N. Nesa, 1S.K. Khan and 3N. A. Siddquie
1
Department of Agronomy and Agricultural Extension, University of Rajshahi, Rajshahi-6205, Bangladesh. 2 Department of Botany, University of Rajshahi, Rajshahi-6205, Bangladesh. 3
Regional W heat Research Institute, Shyampur, Rajshahi, Bangladesh
Abstract: The research work was carried out with twenty wheat varieties/lines to study the effect of source-sink manipulation on grain yield in wheat. Significant variations among the genotypes were observed for grains spike -1 , 100-grain weight and grain yield main spike -1 . Removal of flag leaf caused decreased in grains spike -1 , 100-grain weight and grain yield main spike -1 by 9.94%, 7.65% and 16.88%, respectively. Similarly removal of all leaves caused reduction of grains spike -1 , 100-grain weight and grain yield main spike -1 by 17.17%, 13.27% and 27.92%, respectively. On the other hand, removal of 50% spikelets decreased 41.03% and 37.01% in grains spike -1 and grain yield main spike -1 and increased 9.44% in 100-grain weight. Similarly, 25% spikelets removal reduced grains spike -1 and grain yield main spike -1 by 25.13% and 23.38%, respectively but increased 4.08% in 100-grain weight. The variety/lines BL-1020, Ananda and Akbar showed high decrease in grains spike -1 s, 100-grain weight and grain yield main -1 spike by defoliation treatment. Key words: W heat, genotype, source and sink Bangladesh that will meet up the demand due to increasing population. In crop plants, the physiological basis of dry matter production is dependent on the source-sink concept, where the source is the potential capacity for photosynthesis and the sink is the potential capacity to utilize the photosynthetic products. If the sink is small, the yield can not be high; and even if the sink is large, the yield cannot be high if source capacity is limited. Maximization of source and its proper utilization by the economic sink is important for improvement of yield potential of the crop. In wheat it has been suggested that modern high yielding varieties are limited in sink which has posed problem in yield increase [3 ]. On the contrarily, it has pointed out that there is a higher degree of source limitation in warmer environments due to earlier senescence of green parts [4 ]. Both source and sink limitation might have caused slow yield improvement in wheat. The effects of both source and sink on grain yield in spring wheat have been studied by manipulating both source and sink organs that change the physiological events of plant development and affect the total dry matter production as well as yield. Considering the above view points, the present study on spring wheat was undertaken to study the effects of source-sink manipulation on grain yield in wheat.
INTRODUCTION W heat (Triticum aestivum L.) is regarded as the most important cereal crop of the world in view of area and production. About two-thirds of the world population lives on wheat grain. Its diverse use as food also signifies its elevated position in the cereal group of the food crops. In Bangladesh, it has assumed the position of second important cereal crop in the recent times. It plays a vital role in the national economy to reduce the gap between the food production and food import. W heat commonly grown in Bangladesh, known as spring wheat, belongs to hexaploid group. In Bangladesh it is the second staple food crop next to rice having an annual production of 7.72 lakh tons and total area of 4.81 lakh hectares [1 ]. The yield potentiality of the varieties cultivated in Bangladesh is much less than cultivars of the other wheat growing countries. The W heat Research Center (W RC) of Bangladesh Agricultural Research Institute (BARI) released some good wheat varieties which yield hardly approached to 3 tons hectare -1 in farmers’ field. But in some of wheat growing countries the yield is much higher even reached to about 8 tons hectare -1 [2 ]. This situation emphasizes on further increase in yield potential for wheat in Corresponding Author:
M.S. Alam, Department of Agronomy and Agricultural Extension, University of Rajshahi, Rajshahi6205, Bangladesh. 258
J. Appl. Sci. Res., 4(3): 258-261, 2008 all leaves had the significant effect on grain spike -1 , 100-grain weight and yield main spike -1 . These source manipulations were cmpared with control and tested by paired t-test. The paired t-test showed significant differences between the control and treatments means of all characters studied (Table 3). It was observed that defoliation of both flag leaf and all leaves caused reduction in grains spike -1 , 100-grain weight and grain yield main spike -1 . Removal of flag leaf caused reduction of grains per spike, 100-grain weight and grain yield main spike -1 by 9.94%, 7.65% and 16.88% respectively. Singh and Kaur [6 ] reported that number of grains spike -1 , 100-grain weight and grain yield spike -1 decreased with the removal of flag leaf in bread wheat. Chowdhary et al.[7 ] also reported that flag leaf removal significantly reduced number of grains per spike, 1000-grain weight and grain yield. Similarly, removal of all leaves caused reduction of 17.17%, 13.27% and 27.92% for grains spike -1 , 100-grain weight and grain yield main spike -1 respectively. Singh and Singh [8 ] studied effects of defoliation of all leaves and observed 30% to 40% reduction in grain yield. W ang et al. [9 ] observed that removing one half of the leaves decreased grain mass spike -1 and single grain mass. It was noticed that removal of all leaves had larger decreasing effects than that of flag leaf alone. The varieties SAN-119, Shotabdi and Agrani were highly affected by defoliation treatments for grains spike -1 but Agrani and SAN-127 caused high reduction in 100-grain weight. The variety SAN-119, Agrani and Shotabdi showed high decrease in grain yield main spike -1 by defoliation treatments.
M ATERIALS AND M ETHODS The field experiment was carried out at Agronomy Field Laboratory, Department of Agronomy and Agricultural Extension, University of Rajshahi, Rajshahi, Bangladesh during the period from 2005 to 2006 to study the effect of source-sink manipulation on grain yield in wheat. The experiment was performed with 20 varieties/lines viz. Kheri, SAN-127, Shotabdi, Sourav, AYT, PYT, BAW -917, TR-1, SAN-119, BAW 936, SAN-92, Balaka, V´ T (Short), BAW -944, Protiva, Gourab, T R-1, SAN-127, Ning, and Agrani. The land was prepared by ploughing with tractor and power tiller followed by laddering. The weeds and stubbles were removed as far a possible. A recommended doses of manures and fertilizers was given in the field. The experiment was laid out in a split plot design assigning the variety/line in the main plot and treatments in the sub-plots. The experiment was replicated three times. A space of 1m was maintained between the main plots in each replication. The size of main plot was 2.5m × 2m. The experimental crops received similar management practices such as land preparation, weed control and others excepting the treatments under study. There were five treatments in source-sink manipulation: T 0 = Control, T 1 = Defoliation of flag leaf, T 2 = Defoliation of all leaves, T 3 = Removal of 50% spikelets and T 4 = Removal of 25% spikelets. The second and third treatments imposed source limitations, where the flag leaf in T 1 and all leaves in T 2 were removed by cutting at anthesis time. The fourth and fifth treatments imposed sink limitations, where 50% spikelets (every alternate spikelets) in T 3 and 25% spikelets (one out of every four spikelets) in T 4 were removed by cutting with scissors at anthesis stage. Ten sample plants were randomly selected from each of the experimental plots. Plants were harvested by uprooting and border plants were discarded to avoid border effects. Data on yield and yield contributing characters and source-sink manipulation were recorded from the sample plants of each treatments. The effect of source-sink manipulation on grain yield in wheat were analyzed through analysis of variance following split-plot design and paired t-test was performed to test the difference between the treatments and control following the method outlined by Steel and Torrie [5 ].
Effects of Sink M anipulation: Effect of sink manipulation by removal of 50% and 25% spikelets are presented in the Table 2. Removal of 50% and 25% spikelets produced significant effect on 100grain weight, grains spike -1 and grain yield main spike -1 . The sink manipulation were compared with control and were tested by pared t-test. The paired ttest showed significant differences between the control and treatments means for grain yield and two sink characters studied (Table-3). 50% spikelets removal decreased of 41.03% and 37.01% in grains spike -1 and yield main spike -1 respectively and increase of 9.44% in 100-grain weight. Ferdous and Shamsuddin [1 0 ] reported that removal of 50% spikelets caused decreased in grains spike -1 and grain yield by 47.56% and 42.03%, respectively and increase in 100-grain weight by 12.95% in spring wheat. Likewise there were 25.13% and 23.38% reduction grains spike -1 and yield main spike -1 respectively and 4.08% increase in 100-grain weight by removal of 25% spikelets. This indicated
RESULTS AND DISCUSSION Effects of Source M anipulation: Effects of source manipulation by removal of flag leaf and all leaves are presented in the Table 1. Defoliation of flag leaf and
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Res., 4(3): 258-261, 2008 Table 1: Effect of source manipulation on grain yield and two important yield contributing characters No. of grains/spike Yield/main spike 100-grain weight (g) ----------------------------------------------------------------------- ---------------------------------------------------------------------------- --------------------------------------------------------------------Flag leaf All leaves Flag leaf All leaves Flag leaf All leaves Variety/ Control removal (T1 ) removal (T2 ) Control removal (T1 ) removal (T2 ) Control removal (T1 ) removal (T2 ) Genotype mean ---------------------------- --------------------------- mean ------------------------------ --------------------------- mean ------------------------ -------------------------Mean Changes with Mean Changes with Mean Changes with Mean Changes with Mean Changes with Mean Changes with control (%) control (%) control (%) control (%) control (%) control (%) SAN-92 34.93 37.47 7.27 36.27 3.84 1.07 1.04 -2.80 1.05 -1.87 3.08 2.98 -3.25 2.80 -9.09 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Balaka 35.12 33.23 -5.38 30.90 -12.02 1.19 1.05 -11.76 0.93 -21.85 3.39 3.05 -10.03 3.04 -10.32 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------V´T (Short) 36.53 35.93 -1.64 34.90 -4.46 1.39 1.36 -2.16 1.14 -17.98 3.83 3.35 -12.53 3.23 -15.67 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------BAW-944 21.92 20.06 -8.49 17.93 -18.20 0.84 0.75 -10.71 0.63 -25.00 3.64 3.61 -0.82 3.33 -8.52 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Protiva 30.93 28.73 -7.11 26.30 -14.97 1.16 0.98 -15.52 0.86 -25.86 3.73 3.52 -5.63 3.37 -9.65 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Gourab 50.03 36.50 -27.04 31.90 -36.24 2.28 1.62 -28.95 1.33 -41.67 4.61 4.44 -3.69 4.24 -8.03 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------TR-1 47.34 34.80 -26.49 34.27 -27.61 1.98 1.39 -29.79 1.35 -31.82 4.24 4.12 -2.83 4.03 -4.95 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------SAN-127 24.57 21.53 -12.37 19.27 -21.57 0.67 0.61 -8.95 0.75 -2.99 2.75 2.31 -19.63 2.20 -23.63 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Ning 49.73 41.93 -15.68 42.97 -13.59 1.95 1.69 -13.33 1.49 -23.59 4.24 4.10 -3.30 3.84 -9.43 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Agrani 42.77 36.41 -14.77 30.80 -27.89 2.01 1.37 -31.84 1.08 -46.27 4.71 3.76 -20.17 3.58 -23.99 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Kheri 44.03 38.33 -12.95 36.71 -16.63 2.02 1.62 -19.80 1.42 -29.70 4.59 4.38 -4.58 3.97 -13.51 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------SAN-127 32.87 33.13 0.79 33.09 -0.67 1.26 1.13 -10.32 1.08 -14.29 3.86 3.46 -10.36 3.29 -14.77 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Shotabdi 41.90 37.57 -10.33 28.60 -31.74 1.73 1.33 -23.12 1.06 -38.73 4.14 3.70 -10.63 3.61 -12.80 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Sourav 40.10 37.67 -6.31 34.30 -14.46 1.51 1.26 -16.56 1.17 -22.52 3.77 3.39 -10.08 3.20 -15.12 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------AYT 35.33 42.33 19.81 37.10 -5.01 1.19 1.34 12.61 0.81 -31.93 3.36 2.99 -10.48 2.71 -18.86 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------PYT 33.62 25.60 -23.85 30.20 -10.17 1.33 0.96 -27.82 1.09 -18.05 3.91 3.74 -4.35 3.51 -10.23 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------BAW-917 44.02 43.97 -1.93 34.93 20.65 1.76 1.66 -3.49 1.13 -34.32 3.78 3.85 1.85 3.52 -6.88 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------TR-1 42.45 40.17 -5.37 35.63 -16.06 1.72 1.50 -12.79 1.26 -26.74 4.23 3.77 -10.87 3.49 -17.49 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------SAN-119 50.10 33.43 -33.27 31.87 -36.38 2.35 1.50 -35.32 1.42 -40.43 5.09 4.75 -6.68 4.46 -12.38 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------BAW-936 42.48 44.50 4.76 38.83 -8.59 1.48 1.39 -6.08 1.16 -21.62 3.49 3.24 -7.16 2.80 -19.77 Mean 39.04 35.16 32.34 1.54 1.28 1.11 3.922 3.62 3.40 Table 2: Effect of sink manipulation on grain yield and two important yield contributing characters No. of grains/spike Yield/main spike 100-grain weight (g) ----------------------------------------------------------------------- ---------------------------------------------------------------------------- --------------------------------------------------------------------50% spikelets 25% spikelets 50% spikelets 25% spikelets 50% spikelets 25% spikelets Variety/ Control removal (T3 ) removal (T4 ) Control removal (T3 ) removal (T4 ) removal (T3 ) removal (T4 ) Genotype mean ---------------------------- --------------------------- mean -------------------------------------------------------- mean ------------------------- -------------------------Mean Changes with Mean Changes with Mean Changes with Mean Changes with Mean Changes with Mean Changes with control (%) control (%) control (%) control (%) control (%) control (%) SAN-92 34.93 26.67 -23.64 34.93 -5.72 1.07 0.87 -18.69 1.10 -5.61 3.08 3.41 10.71 3.17 2.92 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Balaka 35.12 20.30 -42.19 29.50 -16.00 1.19 0.82 -31.09 1.01 -15.13 3.39 3.79 11.79 3.57 5.31 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------V´T (Short) 36.53 22.83 -37.50 33.73 -7.66 1.39 0.93 -33.01.27 -8.63 3.83 4.29 12.01 4.03 5.22 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------BAW-944 21.92 15.37 -29.88 25.30 -7.39 0.84 0.67 -20.24 1.03 -1.19 3.64 4.17 14.56 4.02 10.44 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Protiva 30.93 18.37 -40.60 23.43 -24.25 1.16 0.75 -35.34 0.96 -17.24 3.73 4.29 15.01 4.09 9.65 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Gourab 50.03 22.43 -55.17 28.90 -42.23 2.28 1.09 -52.19 1.29 -43.42 4.61 5.08 10.43 4.77 3.69 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------TR-1 47.34 20.83 -55.99 30.10 -36.42 1.98 0.95 -52.02 0.94 -52.52 4.24 4.56 7.55 4.29 11.79 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------SAN-127 24.57 22.17 -9.77 33.23 -5.45 0.67 0.69 2.99 0.93 23.88 2.75 3.22 17.09 2.89 5.09 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Ning 49.73 27.10 -45.51 34.03 -31.57 1.95 1.15 -41.03 1.41 -27.69 4.24 4.38 3.30 4.23 0.23 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Agrani 42.77 24.57 -42.55 26.87 -37.18 2.01 0.92 -54.23 1.16 -42.29 4.71 4.45 1.06 4.47 0.64 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Kheri 44.03 30.37 -31.02 36.87 -16.26 2.02 1.48 -26.73 1.74 -13.86 4.59 4.89 6.54 4.79 4.36 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------SAN-127 32.87 29.40 -10.56 27.34 -15.82 1.26 1.29 -3.97 1.08 -14.29 3.86 4.46 18.14 4.54 15.53 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Shotabdi 41.90 21.52 -48.64 28.76 -31.36 1.73 0.99 -42.77 1.12 -35.26 4.14 4.51 -8.94 4.35 5.07 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Sourav 40.10 27.67 -30.99 28.13 -29.85 1.51 1.21 -19.86 1.46 -3.31 3.77 4.38 16.18 4.08 8.22 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------AYT 35.33 21.23 -39.91 42.03 -37.62 1.19 1.17 -1.68 1.31 -5.04 3.36 3.71 10.41 3.28 -2.68 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------PYT 33.62 20.40 -39.32 27.93 -16.92 1.33 0.92 -30.83 1.13 -15.08 3.91 4.32 10.49 4.08 4.35 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------BAW-917 44.02 24.50 -44.34 32.53 -26.10 1.76 0.99 -43.75 1.25 -28.98 3.78 4.15 9.79 4.02 6.35 -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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J. Appl. Sci. Res., 4(3): 258-261, 2008 Table 2: Continued TR-1 42.45 22.63 -46.69 31.43 -25.96 1.72 0.94 45.39 1.29 -25.00 4.23 4.43 4.73 4.26 0.71 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------SAN-119 50.10 17.74 -64.59 27.47 -44.63 2.35 0.88 -62.56 1.36 -42.13 5.09 5.20 2.16 4.99 -1.96 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------BAW-936 42.48 24.33 -42.72 39.61 -6.77 1.48 0.86 -41.89 1.38 -6.70 3.49 3.77 8.02 3.59 2.87 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Mean 39.04 23.02 29.23 1.54 0.97 1.18 3.92 4.29 4.08
Table 3: Effects of source-sink m anipulation on grain yield and two other yield contributing characters Treatm ents Grains per spike (no.) Grain yield per m ain spike (g) 100-grain weight (g) Control 39.04 1.54 3.92 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of flag leaf 35.16 1.28 3.62 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of all leaves 32.34 1.11 3.40 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of 50% spikelets 23.02 0.97 4.29 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of 25% spikelets 29.23 1.18 4.08 Changes w ith control (% ) Rem oval of flag leaf -9.94** -16.88** -7.65** ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of all leaves -17.17** -27.92** -13.27** ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of 50% spikelets -41.03** -37.01** 9.44** ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Rem oval of 25% spikelets -25.13** -23.38** 4.08** ** indicates significant at 1% level of probability
that the varieties/lines included in the present study had the potentiality to further increase in sink size though its development was affected by source limitation. Ma et al.[1 1 ] observed that the partial degraining (removal of spikelets) decreased grains per spike by 51%. Roy and Salahuddin [1 2 ] studied the effect of spikelets removal and reported that spikelets removed from spike at anthesis period increased grain weight up to 14% . On the whole study of source-sink manipulation in the present materials showed removal of source organs had decreasing influences on the sink development- grains number spike -1 , grain size and concequently grain yield. On the contrary, reducing sink by removal of spikelets had as increasing effect on grain size which indicates possibility of further increase in grain size if sufficient source is provided.
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Steel, R.G.D. and J.H. Torrie, 1960. Principles and procedures of statistics. McGraw Hill B ook C. Inc. New York. 6. Singh, G. and N.K.S. Kaur, 1990. Relative importance of flag leaf blade on grain filling in wheat genotypes. Agril. Sci. Digest., 10(2): 105-109. 7. Chowdhary, M.A., N. Mahmood, T .R. Rashid and I. Khaliq, 1999. Effect of leaf area removal on grain yield and its components in spring wheat. RACHIS., 18(2): 75-78. 8. Singh, D. and D. Singh, 1992. Effect of leaf blade and awn on grain yield of rainfed wheat (Triticum aestivum L.) at different stages of spike development. Indian J. Agric. Sci., 62(7): 468-471. 9. W ang, Z., Y. Yin, M.He, H.Cao, Z.L. W ang, Y.P. Yin, M.R. He and H.M. Cao, 1998. Source sink manipulation effect on postanthesis photosynthesis and grain setting on spike in winter wheat. Photosynthetica., 35(3): 453-459. 10. Ferdous, J. and A.K.M . Shamsuddin, 2001. Effects of source-sink manipulation on grain yield and important sink characters in spring wheat. Bangladesh J. Pl. Breed. Genet., 14(2): 7-12. 11. Ma, Y.Z., C.T. Mackown, D .V. Sanford and S.D. V an., 1990. Sink manipulation in wheat: compensatory changes in kernel size. Crop Sci., 30(5): 1099-1105. 12. Roy, S.K. and A.B.M. Salahuddin, 1994. Effect of spikelet thinning on individual seed weight and seed yield of wheat under two sowing dates. J. Appl. Seed Production., 12: 83-85.
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