Orriiurl Jow.rial of Agricultitrul Scietrces 75 (3): 160-6 1, March 2005
Effect of mepiquat chloride, a growth retardant, on seed yield and yield components
in
common vetch
(Vicia
sativa)*
M TAN' and S TEMEL2
Atatiil"k University, Faculty ofrlgriculture, Erzurum, Turkey 25240
Received: 23 November 2003
Key words: Common vetch, Vicia sativa, Growth retardant, Mepiquat chloride
The common vetch (Vicia sativa L.) produces weak stems and shoots which make them susceptible to lodging when grown for seed production. Excessive vegetative growth and lodging of common vetch grown for seed interferes high seed production and easy harvest. The closed canopy reduces sunlight penetration, increases relative humidity, and the results can reduce the efficiency of photosynthesis. Plant- growth retardants have been used successfully to reduce lodging and increase seed yield of many crops. They when are applied at proper rates, seed yield and yield components can increase, otherwise the benefits of the growth regulators cannot occur (Virgona 1997, Young et a!. 1999, Biles and Cothren 200 1). Since infonnation is not available on effect of growth retardants on seed yield of common vetch, this experiment was conducted to evaluate effects of mepiquat chloride as a plant growth retardant on seed yield and yield components of common vetch.
The experiment was conducted with common vetch during 2 growing seasons (2002 and 2003) at Erzurum, Turkey. Rainfall and mean monthly temperatures for the growing season (April-September) were 207.9 mm and 14.1°C; 228.4 nxn and 16.3"C in 2002 and 2003 respectively.
The experimental field was located in the eastern Anatolia of Turkey, 1 850 m above sea-level. Soil was loamy in texture, low organic matter (1.20%) and P (12.9 kgiha), but rich in K ( I 784.5 kgha), withpH 7.6.
The crop received the growth retardant mepiquat chloride (Pix) in 2 successive years (2002 and 2003). The mepiquat chloride was applied at 5 rates of O,25,50,75 and 100 g active ingredient (a i)!ha. Mepiquat chloride rates were replicated 4 times in randomized block design.
The row-to-row spacing was 25 cm and seeding rate was 120 kglha. All plots received 20 kg Nlha and 40 kg P,O,iha at establishment. Plots were harvested when most of the seed pods m~ned brown by cutting an area of 3 m2.
Ten sample plants!plot were randomly selected to determine the plant height, branches and pods!plant. Ten
*Short note
'Professor, ?Scientist, Departme~lt of Agronomy
pods were taken from each plant and seed number and weight1 pod were determined. The degrees of lodging were assessed on the basis of 0 (no-lodged) to 10 (completely flattered canopy) scale according to Wiltshire et al. (1989).
Since interaction of year x treatment on all parameters
was not consistent, the results presented are means of the 2 years.
Plots treated with 50 and 75 g a i k a had a significantly greater seed yield than that of 0 and 25 g a ika-treated plots, but further increase in dose (100 g a ilha) decreased the yield significantly (Table 1). The lowest seed yield was obtained from untreated plots (1 476 kgka). Seed yield increased from 1 476 kglha to 2 041 kghaand 2 092 kgthawith application of 50 and 75 g a i/ha. Harvest index was significantly increased by mepiquat chloride application, but the differences in harvest index with application rates of 25,50,75 and 100 g a i h a were not significant statistically. Untreated plots had the longest plant (5 1.8 cm). Mepiquat chloride treatments greatly shortened plants; higher rates applied were especially effective in reducing plant height. The untreated plots produced plants with thin stem (2.33 mm). There was a significant increase in stem width with the increasing application rate up to 50 g a il ha.
Untreated plots gave less podslplant than the treated plots, although 0,25, and 100 g a i/ha rates were not statistically different. The increase in podsfplant was greater at the 50 and 75 g a i k a rates. When mepiquat chloride was applied, the seed nunzber and weightlpod increased compared with the control. Higher 1 000-seed weight was obtained at 25 g a i/ha rate of mepiquat chloride application than both high concentrations and the control (Table 1).
Mepiquat chloride reduced the lodging and this effect increased with increasing level of concentration. Lodging was severe in the untreated crop with a score of 6.13, while the lodging score in mepiquat chloride-treated plots was 4.29- 3.42. Mepiquat chloride application prevented lodging but not completely.
The results indicated that application of mepiquat chloride can improve the seed yield of common vetch. Higher seed
March 20051 COMMON VETCH RESPONSE TO MEPIQUAT CHLORIDE 161 Table 1 Effect of mepiquat chloride rates on seed yield and yield components of common vetch
Application Pods1 Seeds1 Seed weight 1 000-seed Lodging Seed Harvest Stem Stem Branches/ rate plant pod (glpod) weight (g) (0. no-lodged) yield index hight width plant
(g a ilha) (kgiha)
(%I
(cm) (m)0 13.8" 4.22" 0.22gh 55.gb 6.13" 1 476d 27.0b 51.Sa 2.33c 2.47 25 14.6" 4.47"" 0.266" 59.7d 4.29"" 1 652'* 29.8" 49.TAb 2.39" 2.46 5 0 16.4" 4.60k 0.270" 58.3"h 3.71' 2 041dh 31.7" 46.3b 2.55"b 2.74 75 17.5" 4.89" 0.269" 55.0" 3.83' 2 092" 32.0" 46.5~~ 2.70" 2.86 100 14.1b 4.8Iab 0.265" 54.6b 3.42' 1 796k 30.3" 46Sb 2.63a 2.53 LSD 1.6 0.27 0.023 3.8 0.60 267 2.6 4.1 0.2 1 NS (P = 0.05)
Figures with diffcrent letters indicate significant difference from each other yields were obtained at 50-75 g a i/ha rates. Yield increases
were best explained by increases in the poddplant. seed number and weightlpod with mepiquat chloride application (Table I ).
The results showed that mepiquat chloride application shortened the plant height and thereby lodging was relatively prevented. The podsiplant were reduced by application of mepiquat chloride (Nichols et al. 2003). Preventing lodging may make the environment within the crop canopy more favourable for sunlight penetration. Other reason for improved seed set and development could be improved assimilates production and distribution in the non-lodged plants (Young eta/. 1999).
SUMMARY
Undesired vegetative growth and lodging o f conllnon vetch (Vicio sativa L.) grown for seed prevent high seed production. But, there is a possibility that lodging could b e reduced by growth retardants. The effects ofmepiquat chloride applied at different rates on seed yield ofcommon vetch @ 50
g a i h a is the optimum recommended application dosage for colnmon vetch, because the lodging was reduced and seed yield was also high at this rate.
REFERENCES
Biles S P and Cothren J T. 2001. Flowering and yield response of cotton to application of mepiquat chloride and PGR-IV. Crop Science 41(6) : 1 834--7.
Nichols S P, Snipes C E and Jones M A. 2003. Evaluation of row spacing and mepiquat chloride in cotton. The Journal of Cotton Scieirce 7(4) : 148-55.
Virgona J M. 1997. The effect of paclobutrazol on seed yield components of Tr$oli~on subrerraneum. (in) Proceedings of the XVIII G~,assland Congress, held during 8-1 7 June 1997 at Winnipeg Saskatoon, Canada, vol2, pp 43-4.
Wiltshire J J J, Hebblethwaite P D, Esslemont R E, and McGilloway D A. 1989. The use of growth regulator RSW0411 in seed crops of Lolium perenne L. Grass and Forage Science 44(2) :
139-50.
Young W C 111, Chilcote D 0 and Younberg H W. 1999. Chemical dwarfing and the response of cool-season grass seed crops to spring-applied nitrogen. Agrono~ny Journal 91(2) : 344-50.
