Influence of nitrogen and row spacing on Sesame (Sesamum indicum L.) growth and yield attributes

The experiment was carried out to examine sesame growth and yield response to nitrogen and row spacing. Factorial experiments were carried out in randomized complete block design with split plot arrangement. Main plots were allotted to row spacing (30, 45 and 60cm) and different rates of nitrogen (0, 40, 80 and 120 kgha) were placed in sub plots. Data on growth and yield traits were recorded using standard manner up to harvest maturity. The results indicated that the impact of nitrogen and row spacing on.number.of branches plant, number.of capsule plant, number.of seeds capsule, 1000 grains weight, biological yield, seed.yield and harvest.index were found significant. However their interactive effects were non-significant. Fertilization of nitrogen at.the rate of 80.kg.ha significantly resulted in maximum.number.of branches plant (20), number.of capsule plant (122), number.of seeds capsule (57), 1000 grains weight (3.6g), seed yield (375.kgha) and harvest index (16%), while.maximum.biological (2967.4kgha) was.recorded.with 120.kg.N.ha. Likewise, in case of row spacing, 45cm apart rows resulted in maximum.number.of branches.plant (19.4), number.of capsule.plant (120.2), number.of seeds capsule (55.5), 1000.grains weight (3.5 g), seed yield (351 kgha) and harvest index (16%) while more biological yield (3393.kgha) were observed in 30cm apart rows. Hence nitrogen fertilization at.the.rate.of 80.kg.ha with 45cm row spacing is recommended to be superior to get higher sesame yield under climatic conditions of Peshawar valley, Pakistan.


Introduction
Sesame (Sesamum indicum L.) locally called til, is an annual erect plant of varying varieties and types belong to pedaliacea family, grown from very ancient times for its grains purposes from which oil is extracted and utilized as food and for flavoring purposes.It is of various shapes and nature having erect, branched and tall stem 60 to 120cm tall.It bears fruit in the form of pod which is 2.5 to 8.0cm in length and of 0.5 to 2.0cm diameter.Maturing of pods starts from bottom and runs upward also lower pods start shattering until the upper ones mature.Seeds are also of two types cream and black in color ovate and small in size.Mostly preference is given to cream colored seed.Sesame is short day crop and normally flowers in 42 to 45 days [1].In the world it is reckoned as oldest oilseed and spicy crop.Containing approximately 25% protein and 50% oil by composition [2].Oil extracted from sesame is also considering as the most stable and preferred vegetable oil due to presence of antioxidants (sesamolin, sesamol and sesamum) which give it a distinct nature.Sesame is one of the oldest spice and oilseed crop in the world [3].Oil extracted from seasame contains 40% unsaturated fatty acids in the form of linoleic and oleic acid each, and 14% saturated fatty acids [4].The carbohydrate composition ranges from 16 to 18% while that of protein ranges from 17 to 19% [5].Due to presence of linolenic acids its industrial value increases and is used in production of perfumes and in medicinal drugs.Its total production is 3.66 million tons throughout the world with Africa singly contributing 0.95 million tons, which is very low and is due to lack of adequate agricultural inputs like fertilizers, improved varieties, and other essential agrochemicals as well as poor agronomic practices [6].Significant seed losses during threshing are also cited as factors for the low production and productivity of the crop.It is kharif crop and thorough well in regions where temperature is high throughout the growing season due to its tolerance it grow well in hottest months of the years and is one of the few crops that grow well in July and in early August [7].Sesame grows well in dry conditions and can tolerate drought as well also respond well to rainfall if waterlogging is avoided.Some cultivars can thorough well in rainfall up to 450 mm.In Pakistan 77.6 ha area is cultivated with sesame with 31.1 tons production annually.In Khyber Pakhtunkhwa the crop is grown on 0.1 ha area with 0.1 tons production annually and average yield is 1000 kg ha , also raising N application from 71 to 142 kgha -1 plant height, no of capsules plant -1 , size of capsule, grain weight plant -1 , and grains yield ha -1 were improved.Also, [18] reported increment in number of branches, seed index, capsule plant -1 , and grain yield plant -1 with application of N up to 120 kgha -1 .Keeping in mind the above literature the present study were carried out to optimized N application and row spacing for remarkable growth and yield of sesame.

Materials and methods
To investigate the response of sesame growth and yield to varying doses of nitrogen and row spacing an experiment was carried out at the Agronomy Research Farm of The University of Agriculture Peshawar during summer season 2014.Experimental area is situated in Peshawar at 34.01 0 N latitude, 71.35 0 E longitude and at an altitude of 350 m above sea level.The climate of Peshawar valley is continental type and is situated about 1600 km north of the Indian Ocean.Major irrigation canal is Warsak canal from the Kabul River.Soil texture is clay loam which has 0.87% low organic matter and the proportion of other nutrients like phosphorus and potassium are 6.57and 121 mgkg -1 respectively, pH (8.2) is alkaline and calcareous in nature [19].The factorial trial was carried out in randomized complete block design with split plot arrangement possessing three replications.Three row spacing (30, 45 and 60cm) were assigned to main plots while nitrogen rates (0, 40, 80 and 120 kgha -1 ) were placed in the sub-plots.There were 5 rows in each sub plot.Field was irrigated on 21-06-2014 and land preparation was carried out on 27-06-2014.Sowing was carried out at morning on 28-06-2014.Phosphorus fertilization at the rate of 60kgha -1 was applied.Seed was sown at the rate of 5 kgha -1 and all other field practices were performed uniformly during the whole growing season.Emergence was started on 02-07-2014 three days after sowing.First irrigation was given 4 days after emergence and the field was three times irrigated during the whole growing season.Severe attack of bacterial leaf blight was noticed twice, first 17 days and second 40 days after emergence which was treated with lambda cylothrin EC-200.Factors studied in the experiment were:

Number.of seeds.capsule -1
Data analysis showed that nitrogen (N) and row spacing (RS) had significant effects on number.ofseeds.capsule - while their interaction were found non-significant (Table 1).Nitrogen application at the rate of 80kgha -1 produced maximum number.ofseeds.capsule - (55.67) while minimum number.ofseeds.capsule - (48.89) were recorded in control plots.Similarly, narrow row spacing (30cm) produced minimum number.ofseeds.capsule - (49.70) while maximum number.ofseeds.capsule - (55.25) were observed at 45cm apart rows.2).From the data it is cleared that highest thousand.seeds.weight(3.6 g) were observed with the application of 80 kg N ha -1 matched with control plots (3.3 g).Likewise, narrow row spacing (30cm) resulted in lowest thousand.seeds.weight(3.3 g) while highest thousand.seeds.weight(3.5 g) were observed with 45cm apart rows.Seed.yield (kg.ha -1 ) Statistical analysis of data presented in Table 2 cleared that seed.yield was significantly affected by nitrogen and row spacing while N x RS interaction was found non-significant.Application of nitrogen at the rate of 80 kgha -1 resulted in maximum grain.yield(375.1 kgha -1 ) while minimum grain.yield(288.6 kgha -1 ) was noted in control plots.In case of row spacing, highest grain.yield(350.9 kg ha -1 ) was observed at 45cm apart rows whereas lowest seed.yield(340.7 kgha -1 ) was noticed with 60cm row spacing.

Biological.yield (kg.ha -1 )
Data analysis indicated that nitrogen and row spacing had significantly affected biological.yieldwhile the interaction of nitrogen and row spacing was found nonsignificant (Table 2).Highest biological.yield(2967.4kgha -1 ) was observed with the application of 120 kg N ha -1 whereas lowest biological.yield(2472.1 kgha -1 ) was resulted from control plots.Likewise, 30cm row spacing produced maximum biological.yield(3393.0kgha -1 ) while minimum biological.yield(2262.6 kg.ha -1 ) was observed at 60cm row spacing Harvest.index.(%).Data analysis concerning harvest.index.showedthat both nitrogen (N) and row spacing (RS) had significant effects whereas N x RS interaction was found nonsignificant (Table 2).Nitrogen application at the rate of 80 kgha -1 resulted in maximum harvest.index(15.9%) whereas minimum harvest.index(14%) was recorded in control plots.Similarly, minimum harvest.index(14.5%) was recorded at 30cm apart rows while maximum harvest.index(15.9%) was observed at 45cm row spacing.

Discussion
From data analysis it is revealed that both nitrogen (N) and row spacing (RS) have significantly affected number.ofbranches plant -1 while the interactive effect of (N x RS) were non-significant.Control plot gives minimum number.ofbranches plant -1 (15.8).With each.increment.ofN number.ofbranches.plant - increased and maximum branches plant -1 (20) were reported with 80 kg N ha -1 .However further.increase in N has no significant.effecton number.ofbranches plant -1 .Data regarding row spacing, narrow row spacing (30cm) gives minimum number.ofbranches.plant - (16.5) while row spacing with 45cm recorded maximum (19.4) no of branches plant -1 .Number. of branches.plant - increased.withapplication.ofnitrogen.Sesame planted at an inter.rowspacing.of7.5cm were.shorter,having lower.LAI, TDM.and number.ofbranches.plant - compared.withthose.plantedat wider.spacing.Possible reason is that at close spacing number.ofplants per.unit increases compared.withwider.spacing.Due to which completion for light, space and nutrients increases however at wider spacing competition among plants decreases thereby producing taller plants with high LAI, TDM and number.ofbranches.plant - .

Similar.results.were also reported.by [21].
Who investigated maximum number.ofbranches.plant - with application.of120 kg N ha -1 .Data analysis revealed that both nitrogen (N) and row spacing (RS) had significantly affected number.ofcapsules plant -1 while.interaction.between(N x RS) was found.non-significant.In control plots minimum number of capsules plant -1 (107.6) were observed.With each increment of N capsules plant -1 increases and maximum capsules plant -1 (122.0) were reported with 80 kg N ha -1 .Thereafter, further increment in N did not enhanced capsules plant -1 .Minimum capsules.plant - (111.2) were reported in plots.withnarrow row spacing (30cm), while plots having row spacing 45cm apart recorded maximum (120.2) number.ofcapsule plant -1 .Yield.components such as number.ofcapsules.plant - , capsule.yield.plant - , seed.yield.plant - and seed.yield.ha - were all optimized.atmoderate.N level (80 kg.N ha -1 ) and not the highest.N level (120kg.ha - ) as in.growth.characters.Our results are in conformity with that of [22] who investigated that excessive nitrogen only improve plant growth while reduces yield and fruit number.Statistical.analysis.ofthe data.showed.thatnitrogen.androw spacing had significantly.affectednumber.ofseeds.capsule - while interaction.between(N x RS) was.found non-significant.Nitrogen application at the rate.of80 kgha -1 reported maximum.number.ofseeds capsule -1 (55.67), followed.by120kg N ha -1 while control plots yields minimum.number.ofseeds capsule -1 (48.89).In case of row spacing, minimum (49.70) numbers of grains capsule-1 were recorded in plots with narrow row spacing 30cm apart.Row spacing with 45cm apart gives maximum number of capsules plant -1 (55.25).More grains capsule -1 were recorded at application of higher doses of nitrogen while lower doses reported minimum number of grains capsule -1 .This might be due to high nitrogen use efficiency and more interception of sunlight due to more number of leaves and and as a result more photo assimilates go to seeds.These results are in conformity with findings of [23] reported that increase in nitrogen application had increased the number of seeds capsule -1 .Date regarding 1000 grains weight was significantly enhanced by application of N. Statistical analysis of the data revealed that 1000 grains.weight.increasedwith each increment.ofnitrogen and highest thousand.grains.weight(3.6g) were recorded with 80 kg.N.ha -1 compared to control plots (3.3g) .In case of row spacing the maximum thousand seeds weight (3.5g) were reported in 45cm rows apart, followed by 60cm and 30cm respectively.The interactive.effect.ofnitrogen and row spacing on thousand seeds weight was found non-significant.This result is supported with the findings of [23] who reported the highest thousand grain weight (g) at 80 kg N ha -1 .Form analysis of data it was observed that both N and RS signify seed yield while interaction between (N x RS) was found non-significant.Nitrogen application at the.rate.of80 kg.ha -1 recorded maximum.yield(375.1 kg.ha -1 ), while minimum.seed.yield(288.6 kg.ha -1 ) was reported in control.plots.Plots with 45cm row spacing recorded maximum.seedyield (350.9 kgha -1 ) compared with plots.havingrow having row spacing 60cm apart recorded minimum yield (340.7 kgha -1 ).These results are in corroboration with the findings.of[23, 24] who investigated more grain yield with increased application of nitrogen.
[12] also reported that sesame seed yield ha -1 increased with increasing plant density up to a maximum means narrow row spacing.Data regarding biological yield showed that both N and RS statistically affected biological yield.Nitrogen application at the rate of 120kgha -1 recorded maximum (2967.4kgha - ) biological.yield, while minimum (2472.1 kgha -1 ) biological yield was observed.incontrol.plots.Similarly plots having row spacing 30cm apart reported highest biological yield (3393.0 kg.ha -1 ), while.minimumbiological yield (2262.6 kgha -1 ) was.recorded in plots.with60cm apart rows.However the interaction of nitrogen and row spacing (N x RS) was found non-significant.This increment in biological yield may be attributed to more number.ofpods plant -1 , increased plant.heightand more number.ofbranches.plant - that might enhances total biomass of the plant and resulted in maximum biological yield.These results are in conformity with the findings of [25, 26] who reported that increment in nitrogen application improve different yield components which as a result enhanced the biological yield.The reason for maximum biological yield with 30cm row.spacing.mightbe due to high number of plants m -2 .Analysis of the data.revealed.thatboth N and RS significantly affected harvest index.Maximum harvest index (15.9%)was reported with 80 kg.N ha -1 while minimum harvest index (14%) was observed in control plots.Similarly highest harvest index (15.9%)was recorded at 45cm row spacing whereas minimum harvest index (14.5%)were recorded at 30cm apart rows.However the interaction of nitrogen and row spacing (N x RS) was found non-significant.This result was also supported by [21, 27] who observed that phosphorus and nitrogen application had significantly affected grain yield.As harvest index is correlated with grain yield, therefore increase in grain yield increase harvest index.

Conclusion
It is concluded from the results that application of nitrogen @ 80 kg.ha -1 with 45cm row spacing had significantly improved the yield and yield components of sesame except biological yield which optimized with 120 kg.N ha -1 and 30cm row spacing, whereas growth characters were also optimized with 80 kg.N ha -1 with 45cm apart rows.Highest harvest index was recorded with 80 kg.N ha -1 with 45cm row spacing.

.of branches.plant -1
Number.of branches.plant - were estimated in five plants selected randomly in each subplot and then averaged.

Table 2 . Thousand.seeds weight, seed yield, biological.yield and harvest.index of sesame as affected by various levels of nitrogen and row spacing
Means in rows or column followed by the same letters are not significantly different at p ≤ 0.05 by using LSD test