evaluation of potassium application effect on grain yield, oil and

Sarhad J. Agric. Vol.29, No.03, 2013

EVALUATION OF POTASSIUM APPLICATION EFFECT ON GRAIN YIELD, OIL AND PROTEIN CONTENT OF BRASSICA (BRASSICA NAPUS L.) INAMULLAH1*, ANSAAR AHMAD1, MIFTAHUD DIN2, ASAD ALI KHAN1 and MUHAMMAD SIDDIQ3 1. 2. 3.

Department of Agronomy, The University of Agriculture Peshawar - Pakistan Kyhber Pakhtunkhwa Agricultural Research System, Peshawar - Pakistan National Agricultural Research System, Islamabad - Pakistan *Correspondence author: [email protected]

ABSTRACT Potassium response on yield, yield components, oil and protein contents of brassica cultivars was evaluated in a field study at University of Agriculture, Peshawar during winter 2010-11. Three cultivars (Abasin-95, Bulbul-98 and Durr-e NIFA) and four potassium levels (0, 30, 60, 90 and 120 kg ha-1) were compared. Randomized Complete Block design with factorial combination of cultivars and potassium levels was used with four replications. Seed was sown at the rate of 5 kg ha-1 keeping row to row distance of 35 cm. Nitrogen and phosphorus were applied at the rate of 80 and 60 kg ha-1 from urea and DAP respectively. Half N was applied at sowing and the other half at the beginning of flowering. Thinning was carried out to maintain uniform population by keeping about 5 cm plant to plant distance. Weeds were controlled manually. The crop was irrigated when needed and at least seven irrigations were given until the physiological maturity. Analysis of data revealed significant difference for the cultivars in grain number silique-1, 1000 grain weight, biological yield, grain yield, harvest index, seed oil yield, seed oil content and protein contents. At par siliques m-2 (9914 and 9878), grain yield (1759 and 1799 kg ha-1), oil yield (767 and 784 kg ha-1) and harvest indices (13.9 and 13.7%) were recorded for Bulbul-98 and Abasin-95, respectively. Maximum grain number silique-1(24), 1000 grain weight (3.5 g) and protein content (26.7 %) for Bulbul-98, maximum biological yield (13189 kg ha-1) for Abasin-95 and maximum oil content (44.3 %) was recorded for Durre-NIFA. K levels affected number of siliques m-2, grains silique-1, 1000 grains weight, biological yield, grain yield, harvest index, seed oil yield, seed oil and protein content. At par harvest indices, biological, grain and oil yields were recorded at K levels of 60, 90 and 120 kg ha-1. At par grains siliques-1, 1000 grain weight, seed oil and protein content were recorded at K levels of 90 and 120 kg ha-1, and maximum siliques m-2 were recorded at K level of 120 kg ha-1. C x K interaction exhibited significant differences for protein content only. It was concluded that Bulbul-98 and Abasin-95 had higher grain yield, seed oil yield and oil contents. Bulbul-98 had more protein content than Abasin-95 and Durre NIFA. On the average, cultivars gave at par grain and oil yield at 60, 90 and 120 kg ha-1. However, they produced at par oil and protein content at 90 and 120 kg ha-1. In light of the above conclusion Bulbul-98 and Abasin-95 are recommended for higher grain and oil yield for general cultivation in Peshawar valley. Potassium @ 60 kg ha-1 is recommended for higher grain and oil yield in brassica. Keywords:

Brassica napus L., potassium, oil and protein contents, grain yield, yield components

Inamullah, A. Ahmad, M. Din, A. A. Khan and M. Siddiq. 2013. Evaluation of potassium Citation: application effect on grain yield, oil and protein content of brassica (Brassica napus L.). Sarhad J. Agric 29(3): 331-337 INTRODUCTION Oilseed Brassicas, rapeseed-mustard accounting for over 13.2% of the world’s edible oil supply are the third most important edible oil source after soybean and palm (Ram and Singh, 1993). The Brassicas, belonging to the Cruciferae family, have about 160 species including Brassica napus, B. campestris, B. nigra, B. carinata, B. juncea and B. oleracea etc. (Weis, 1983). Rapeseed and mustard were grown about 300 BC in the Indus valley as fodder crop. Its oil was used for burning in lamps and as food additive only by the poor. During the Second World War, the oil was used as lubricant (Weiss, 1983). The crop is although a rich source of edible oil (ca. 40% on dry weight basis of seed) but the presence of a fatty acid named erucic acid (C22H42O2, a white waxy solid) in its oil (ca. 48% of the total fatty acid composition) and glucosinolate (the sulfur and nitrogen having compound: C15H20KNO9S2.H2O) in its meal, make it unattractive for human and animal use. These chemicals are considered toxic for both human and animal’s health in addition to bitter taste. Because of these chemicals, Brassica could not get important position as an oilseed crop until 1976 when “Candle” the first strain of a B. campestris L., low both in erucic acid and glucosinulate, was grown in Canada. The name CANOLA (Canadian Oil Low Acid) was used for the first time for such kind of “double low” varieties in 1979. Safe limits for these compounds have been described as less than 2 % erucic acid in oil and less than 30 μ mol g-1 glucosinolates in oil free meal (Grombacher and Nelson, 1992; Downey and Rimmer, 1993). According to Shahidi (1990), the US Food and Drug Administration (FDA) recognized rapeseed and canola as separate species. Introduction of canola type Brassicas in Pakistan has also been successful and popular. During 2008-09, area under rapeseed and mustard was 244900 ha which includes 11700 ha area of canola with total production of

Inamullah, et al. Evaluation of potassium application effect on grain yield…

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198900 tons which includes 11200 tons of canola (MINFA, 2009). In Khyber Pakhtunkhwa, total area under rapeseed and mustard was 17700 ha which includes 1000 ha under with production of 7400 tons which includes 500 tons under canola (MINFA, 2009). The unavailability of new varieties and their seed is one of the biggest hindrances in the vast cultivation of canola in the country. Several research organizations at Federal and Provincial level are doing their best to develop new varieties and produce seed to provide to growers. Being a recent introduction in Pakistan, many aspects of a productive package of production technology need to be unveiled. Among other factors of a successful production technology, the proper amount of nutrients and their time of application are needed to be explored for getting bumper crop of canola. Balanced use of fertilizers, their type, time and method of application play an important role in sustainable crop production. Higher crop productivity depends upon the time, kind and appropriate amount of fertilization (Jan and Khan, 2000). Besides N and P, the use of K has been reported to influence productivity of seed yield and seed oil contents in brassica (Ghosh et al., 1995). Kuo and Chen (1980) reported that K increased the seed oil content of Tower variety of B. napus. Kandil (1983) reported that application of K along with N and P fertilizers improved the seed yield of rapeseed. K increases leaf area and leaf chlorophyll content, delays leaf senescence and thus contributes to a greater canopy photosynthesis and crop growth. Plant needs large quantities of potassium, the uptake of which frequently exceeds the uptake of nitrogen. Plant tissues contain higher K+ ion than other cations. K+ regulates effectively many physiological and biochemical processes inside plants (Bajwa and Rehman, 1996). K affects photosynthesis by affecting the ATP formatting, regulates water and carbon dioxide exchange through stomata as an osmo-regulator, affects protein synthesis by activating enzyme nitrate reductase and transfers sugar to seeds (Wallace, 2001). The use of N and P fertilizer for agronomic crops is well known, well understood and well practiced but the use of potash has got least attention in the past and even now it is being ignored. The use of potash as mineral fertilizer is very low in Pakistan and the ratio of nutrient fertilizer (NPK) is imbalanced. K application in Pakistan for agronomic crops is 0.8 kg ha-1 while world average is 15 kg ha-1 (MINFAL, 2007). At KP Agricultural University Research Farm Peshawar, average soil K content is 120 mg kg-1 of soil (Bhatti, 2002), but the required amount is 150 mg kg-1 (Bajwa and Rehman, 1996). Thus the existing soil K reserves will not be sufficient to supply with K for optimum crop yields. The present study was, therefore, conducted to investigate the effect of different potassium levels on yield and quality of popular brassica cultivars of the Khyber Pakhtunkhwa Pakistan. MATERIALS AND METHODS The experiment was conducted at New Developmental Farm of University of Agriculture, Peshawar during Rabi 2010-11. Three cultivars i.e. Abasin-95, Bulbul-98 and Durr-e-NIFA were sown on 21 October using four levels of potassium (0, 30, 60, 90 and 120 kg ha-1). Sulfate of potash was used as a source of potash. Randomized Complete Block design with factorial combination of cultivars and potassium was used for sowing the experiment with four replications. The size of plot was 5 m x 2.1 m. In each plot there were 6 rows 5 m long and 35 cm apart. Nitrogen was applied at the rate of 80 kg ha-1 and phosphorus at the rate of 60 kg ha-1 from urea and DAP, respectively. Half N was applied at sowing and the remaining half at the beginning of flowering. After the completion of germination, seedlings were hand thinned to maintain a uniform plant to plant distance of 5 cm. Weeds were controlled manually. Hoeing was done when the seedlings were 6-8 cm tall. The crop was irrigated when needed and at least seven irrigations were given to the crop until physiological maturity. Data were recorded on the following parameters: Number of siliques m-2 was recorded by counting the number of siliques in plants in three rows each row one meter long at three different locations in each plot and then averaged and converted into number of siliques m-2. For number of grains silique-1, ten siliques of various sizes were randomly selected and number of grains in each silique was counted. Then average was worked out for the calculation of grains silique-1. Thousand grains were randomly selected from threshed grains in each plot and weighed to record 1000 grains weight in grams. Biological yield (BY) was calculated by harvesting plants of four central rows in each plot, dried, weighed and then converted into biological yield in (kg ha-1) using the formula: BY (kg ha-1) = [{BY (kg) x 10000 (m2)} ÷ {Row to row distance (m) x Row length (m) x No. of rows harvested in each plot}]. For grain yield (GY), the plants of four central rows in each plot harvested for calculating biological yield were dried, siliques were removed and threshed. The threshed grains were weighed and then converted to grain yield (kg ha-1) using the following formula: GY (kg ha-1) = [{GY (kg) x 10000 (m2)} ÷ {Row to row distance (m) x Row length (m) x No. of rows harvested in each plot}]. Harvest index was calculated using the formula: Harvest Index (%) = {(Grain yield ÷ Biological yield) x 100} (Reddy, 2004). Data on regarding oil and protein contents were recorded by collecting random grains samples from each plot and were analyzed for oil and proteins (%) by the instrument FOSS Routine Near Infrared Measurement System (Model 6500 Maryland, USA) at Oilseed Quality Laboratory, Crop Breeding Division, Nuclear Institute for Food and Agriculture (NIFA), Peshawar according to the procedure outlined by Daun et al., (1994). Seed oil yield was calculated by multiplying seed oil content with grain yield and dividing it by 100. The data recorded were analyzed


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statistically using the analysis of variance techniques appropriate for randomized complete block design (Steel and Torrie, 1980). Interaction effects were compared using LSD test at 0.05 level of probability, when the F-values were found significant. RESULTS AND DISCUSSION Siliques m-2 Canola cultivars varied significantly from each other for number of siliques m-2 (Table 1). Higher and at par number of siliques m-2 (9914) was produced by Bulbul-98 and Abasin-95 (9878), respectively while Durre-NIFA recorded significantly lower number of 9035 siliques m-2. Higher number of siliques producing characteristic of Bulbul-98 and Abasin-95 could be attributed to the genetic make up of these cultivars. Number of siliques m-2 was significantly increased with increase in K level. Maximum siliques m-2 (10805) were produced in plot where K was applied @ 120 kg ha-1. Minimum siliques m-2 (8100) were produced by the plants in plots where K was not applied which was statistically different from the plots where K was applied @ 30 which gave 8932 siliques m-2. Furthermore, statistically at par siliques m-2 (10158 and 10051) were produced in plots which received K at the rate of 60 and 90 kg ha-1, respectively. The maximum number of siliques m-2 noted in case of 120 kg K ha-1 could be attributed to the rich soil environments because of the presence of sufficient quantities of K which promoted plant vegetative as well as reproductive growth processes. The results are in line with those of Mahadkar et al. (1996) who reported that increasing the rate of K fertilizer increased the number of siliques. Khan (2004) reported that K application increased number of siliques plant-1. There was no significant effect of the interaction of cultivars and K on the siliques m-2 of canola cultivars, which shows the all the three cultivars responded similarly to the increasing K levels. Table 1. Siliques m-2, grains silique-1 and thousand grains weight (g) of canola cultivars as affected by various potassium levels Treatment Siliques m-2 Grains silique-1 1000 grain weight (g) Cultivars (C)

LSD (0.05) Potassium levels (K) (kg ha-1)

Bulbul-98 Abasin-95 Durre NIFA

9914 a 9878 a 9035 b

24.0 a 22.2 b 18.4 c

3.5 a 3.4 ab 3.3 b

491 0.97 0.13 8100 d 18.6 d 3.0 d 8932 c 20.4 c 3.3 c 10158 b 21.7 b 3.5 b 10050 b 24.0 a 3.7 a 10805 a 22.9 ab 3.6 ab LSD (0.05) 634 1.25 0.17 Interactions C×K Ns Ns Ns Mean values of the same category followed by different letters are significantly different from each other at 5% significance level. Ns: Non-significant 0 30 60 90 120

Grains Silique-1 Cultivars differed significantly from each other in number of grains silique-1 (Table 1). Higher number of grains silique-1 was recorded for Bulbul-98 (24.0) followed by Abasin-95(22.2) and Durre-NIFA (18.4), respectively. Sultana et al. (2007) also stated that cultivar (SAU Sarisha I) produced high number of seed silique-1 as compared to Kollania and improved cultivar Tori 7. Grains silique-1 were significantly increased with higher K application level. Plots where K was not applied produced minimum number of 18.6 grains silique-1, while plot applied with K @ 30 kg ha-1 produced 20.4 grains silique-1. Grains silique-1 (21.7) produced in plot which received K @ 60 kg ha-1 was statistically at par with plot which received K @ 90 and 120 kg ha-1 which produced 24.0 and 22.9 grains silique-1, respectively. These results are in agreement with Abd-EI-Gawad et al. (1990) who reported that increasing levels of K application not only increased the seed yield but also increased the silique number plant-1 and number of grains silique -1. All cultivars responded in a similar pattern to increase in K level and no significant cultivar x K interaction effect was observed on number of grains silique-1. Thousand Grain Weight (g) Thousand grain weight (g) has a direct effect on the formation of final grain yield of a crop. Significant differences were observed among canola cultivars for thousand grain weight (Table 1). Mean values of thousand grains weight of the cultivars revealed that the maximum thousand grain weight was recorded for Bulbul-98 (3.5 g) followed by Abasin-95 (3.4 g) and Durre-NIFA (3.3 g), respectively. The difference in the grain weight of cultivars might be due to the difference in the genetic makeup, leaves per plant and nutrient uptake of cultivars as reported by Sultana et al. (2007). Thousand grains weight significantly increased with increase in K level. Plots where K was


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not applied produced minimum thousand grains weight of 3.0 g; however, significant increase was observed in plots where K was applied @ 30, 60, 90 and 120 kg ha-1 which gave 3.3, 3.5, 3.7 and 3.6 g thousand grains weight, respectively. Our results are in confirmation with those of Khan (2004) who reported that increase in K levels increased grain weight. The differences in mean grain weight were generally related to a short period between anthesis and maturity. At this time, supply of assimilates to the seeds plays a crucial role in the development of seed and probably plants with greater supplies of nutrients are at greater advantage than those under low nutrition (Scott et al.1973). All cultivars responded in similar pattern to increase in K level and there was no significant cultivar x K interaction impact on thousand grain weight of canola cultivars. Biological Yield Biological yield is total output of a crop and depends upon species, growing season and nutrition. Significant differences for biological yield were recorded among different canola cultivars (Table 2). Significantly higher biological yield was produced by Abasin-95 (13189 kg ha-1) followed by Bulbul-98 (12645 kg ha-1) and Durre-NIFA (8189 kg ha-1), respectively. Biological yield was significantly increased with increase in K application level. Minimum biological yield of 11047 kg ha-1 was produced in plots where K was not applied. Significant increase in biological yield was observed in plots which obtained K @ 30 and 60kg ha-1 which produced 11289 and 11468 kg ha-1 biological yield, respectively. Biological yield obtained at 60 kg K ha-1 was statistically at par with yields produced in plots which received K @ 90 and 120 kg ha-1. Misras (2003) reported that K increased biological yield in Brassica specie. Generally, TDM yield increased with increasing rate of fertilizer application. Munir and McNeilly (1987) also reported that increasing rates of K increased the dry matter production of canola. No significant differences were observed in biological yield produced by cultivars in interaction with K. Table 2 Treatment Cultivars (C)

Biological yield (kg ha-1), grain yield (kg ha-1) and harvest index (%) of canola cultivars as affected by various potassium levels Biological yield Grain yield (kg Harvest index (%) (kg ha-1) ha-1) Bulbul-98 12645 b 1759 a 13.9 a Abasin-95 13189 a 1799 a 13.7 a Durre NIFA 8189 c 1076 b 13.1 b

LSD (0.05) Potassium levels (K) (kg ha-1)

121 14.1 0.37 11047 c 1289 c 11.5 c 11289 b 1448 b 12.9 b 11468 a 1653 a 14.3 a 11457 a 1671 a 14.6 a 11445 ab 1664 a 14.6 a LSD (0.05) 156 56.9 0.48 Interactions C×K Ns Ns Ns Mean values of the same category followed by different letters are significantly different from each other at 5% significance level. Ns: Non-significant 0 30 60 90 120

Grain Yield Cultivars differed significantly from each other in grain yield (Table 2). Mean values depicted that maximum grain yield was recorded by Abasin-95 (1799 kg ha-1) which was at par with grain yield produced by Bulbul-98 (1759 kg ha-1) followed by significantly lower grain yield recorded by Durre-NIFA (1076 kg ha-1). Grain yield was significantly increased with increase in K level. Minimum grain yield (1289 kg ha-1) was recorded in plots where K was not applied. However, significant increase in grain yield was recorded in plots where K was applied @ 30 kg ha1 which gave grain yield of 1448 kg ha-1. Further significant increase in grain yield was observed when K level was raised to 60 kg ha-1 which recorded 1653 kg ha-1 grain yield. Grain yield obtained at 60 kg K ha-1 was statistically not significantly different from grain yields produced in plots which received K @ 90 and 120 kg ha-1. The higher grain yield was probably due to increased growth under sufficient amount of macro nutrient available in soil. These results are in agreement with that of Ghosh et al. (1993) who reported that seed yield increased in response to increasing K rates. The interaction of cultivar x K was found to have no significant impact on grain yield showing similar response of canola cultivars to varying K levels. Harvest index (%) Cultivars varied significantly from each other in harvest index (Table 2). Maximum harvest index was recorded for Bulbul-98 (13.9%) followed by at par harvest index of Abasin-95 (13.7%) while Durre-NIFA produced the lowest harvest index of 13.1%. Harvest index increased when K application rate was increased. Minimum harvest index (11.5%) was observed in plots where K was not applied. However, significant increase in HI (12.9%) was noted when K was applied at the rate of 30 kg ha-1. With further increase in K application rate to 60 kg ha-1, the HI was increased to 14.3 %. HI recorded with the application of 60 kg ha-1 K was not significantly different from the harvest indices recorded in plots which received K @ 90 and 120 kg ha-1. These results are supported by Kandil


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(1983) who reported that increasing rate of fertilizer application increased HI. There was no significant effect of the interaction of cultivar x K on the harvest indices of canola cultivars. Oil content (%) Oil content is typically a characteristic of species, cultivars and their genetic makeup but environmental conditions and nutrition also affects its amount. Canola cultivars and K application significantly affected oil content (Table 3). Durre NIFA produced greater oil content (44.3%) followed by Bulbul-98 and Abasin-95 which produced significantly lower oil content (43.6%). Oil content was significantly increased with higher K application level. Plots where K was not applied or where K was applied @ 30 kg ha-1 produced low oil content of (42.3 %). Significantly higher oil contents of 45.1% and 45% were produced in plots which received K @ 120 and 90 kg ha-1 respectively. The increase in oil content confirmed the findings of Misras (2003) who found that K application increase oil content in mustard. Cultivar x K interaction did not significantly affect oil content of canola cultivars. Oil Yield Cultivars differed significantly from each other in oil yield (Table 3). Mean values showed that maximum oil yield was recorded by Abasin-95 (784 kg ha-1) which was at par with oil yield produced by Bulbul-98 (767 kg ha1 ) followed by significantly lower oil yield recorded by Durre-NIFA (477 kg ha-1). Oil yield was significantly increased with increase in K level. Minimum oil yield (545 kg ha-1) was recorded in plots where K was not applied. However, significant increase in oil yield was recorded in plots where K was applied @ 30 kg ha-1 which gave oil yield of 613 kg ha-1. Further significant increase in grain yield was observed when K level was raised to 60 kg ha-1 which recorded 732 kg ha-1 oil yield. Oil yield obtained at 60 kg K ha-1 was statistically not significantly different from oil yields produced in plots which received K @ 90 and 120 kg ha-1. The higher oil yield was probably due to increased growth under sufficient amount of macro nutrient available in soil. The interaction of cultivar x K was found to have no significant impact on oil yield showing similar response of canola cultivars to varying K levels. Seed oil content (%), oil yield (kg ha-1) and seed protein content (%) of canola cultivars as affected by various potassium levels Protein content Treatment Oil content Oil yield (%) (%) (kg ha-1) Cultivars (C) Bulbul-98 43.6 b 767 a 26.7 a Abasin-95 43.6 b 784 a 26.1 b Durre NIFA 44.3 a 477 b 25.8 b LSD (0.05) 0.51 43.5 0.51 Potassium levels (K) 0 42.3 c 545 c 24.1 d (kg ha-1) 30 42.3 c 613 b 24.9 c 60 44.3 b 732 a 26.8 b 90 45.0 a 752 a 27.7 a 120 45.1 a 750 a 27.7 a LSD (0.05) 0.66 51.5 0.76 Interactions C×K Ns Ns * (Fig.1) Mean values of the same category followed by different letters are significantly different from each other at 5% significance level. Ns: Non-significant. * = Significant at 5% level of probability. Table 3

Canola cultivars responded differently in protein content with change in the level of K (Fig.1). All the three cultivars showed lower protein content in plots where K was not applied. In K-control plots, the protein content of Durre NIFA was smaller then Abasin-95 and Bulbul-98. With increase in K level from zero to 30 kg ha-1, mild increase was observed in protein content of all the three cultivars. However, with further increase in K level from 30 to 60 kg ha-1, a very sharp increase was observed in protein content of Durre NIFA, surpassing the protein content of abasin95. Increase in protein content of Bulbul-98 was also sharper. With increase in K level from 60 to 90 kg ha-1, increase in protein content of Abasin-95 was sharper surpassing the protein content of Durre NIFA. With further increase in K content from 90 to 120 kg ha-1, there was a very small increase in protein content of all the three cultivars. At 120 kg K ha-1, protein contents in all the three cultivars were almost the same.


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Fig. 1. Cultivar X Potassium interaction for protein content of Canola

Protein content (%) Perusal of the data regarding protein content of canola cultivars indicated that cultivars, K application and the interaction of cultivar x K had significant effects on protein content (Table 3). Difference in protein content of cultivars was significant. Higher protein content (26.7%) was produced by Bulbul-98 followed by Abasin-95 and Durre-NIFA (26.1%) and (25.8%) respectively, which both produced significantly at par protein contents. Protein content increased with increase in K application level. The highest protein content (27.7%) was recorded with K level of 90 or 120 kg ha-1. Plots where K was not applied produced the minimum (24.1%) protein content, which was statistically different from the protein contents of the plots which received 30 and 60 kg ha-1 K. The increase in protein content with the application of K rate confirmed the findings of Khan (2004), who reported that K was directly proportional to protein contents in oilseed rape. These results are in agreement with the findings of Nordestgaard et al. (1984) also who reported that nitrogen and potassium applications increased protein contents CONCLUSION AND RECOMMENDATIONS It was concluded that Bulbul-98 and Abasin-95 showed higher grain and oil yield despite their seed oil content was lower than Durre NIFA. Bulbul-98 had more protein (%) than Abasin-95 and Durre NIFA. At par grain and oil yields were obtained at potassium level of 60, 90 and 120 kg ha-1, significantly higher than grai and oil yields obtained at 30 kg ha-1. Based on the above conclusion Abasin-95 and Bulbul-98 can be recommended with 60 kg ha-1 potassium for general cultivation in Peshawar valley. ACKNOWLEDGEMENTS We are very thankful to the Director Nuclear Institute for Food & Agriculture (NIFA) and Dr. Iftikhar Ali PSO (NIFA) Peshawar for analyzing the seed samples for oil and protein contents. REFERENCES Abd–El–Gawad, A.A., A. Tabbakh, A.M.A. Abo–Shetaia and A.M. El–Baz. 1990. Effect of nitrogen phosphorus and potassium fertilization on yield components of rape plant. Ann. Agric. Sci., 35: 279– 93. Bajwa, M.I. and F. Rehman . 1996. Soil and fertilizer potassium .In : Soil Science. Bashir, E. and R. Bantal (Eds). NBF, Islamabad. Bhatti A. 2002. Soil fertility status of Malakandher Farm, NWFP Agricultural University Peshawar. Department of Soil & Enviromental Sci., University of Agriculture, Peshawar (Pakistan). Daun, J.K., K.M. Clear and P. Williams. 1994. Comparison of three whole seed near infrared analyzers for measuring quality components of canola seed. J. Am. Oil Chem. Soc. 71(10): 1063-1068. Downey, R.K. and S.R. Rimmer. 1993. Agronomic improvement in oilseed Brassica. Adv. Agron. 50:1-66. Ghosh, D.C., P.K. Panda and P.M. Sahoo. 1995. Response of rainfall rapeseed (Brassica compestris) to NPK. Indian J. Agric. Res. 29: 5–9.


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