Soil moisture is limiting factor of production during rapeseed growing period of Nepal. An experiment was conducted in research farm of oilseed research program (ORP), Sarlahi, Nepal in order to evaluate the performance of elven pipeline varieties of rapeseed under soil moisture stress condition. They were laid out in the randomized complete block design with three replications for two years 2014 to 2016. Separate field blocks for irrigated (non-stress) and drought (stressed) condition were made. Yield from moisture stress (Ys) and non-stress (Ys) were recorded to calculate different drought indices. Variety ICT 2010-3 performs better with the highest tolerance index (TOL), marginal productivity (MP), gross mean productivity (GMP), yield index (YI), yield stability index (YSI), stress tolerance index (STI) and the lowest stress susceptibility index (SSI) and percentage yield reduction (%YR). But in the second-year variety ICT 2001-14 has the highest MP, GMP, YI and STI. Variety ICT 2001-19 has the highest TOL and YSI, and the lowest SSI and %YR. On an average ICT 2001-14 has the highest MP, GMP and STI and these indices are significantly positively correlated with stressed and non-stressed yield. So, ICT 2001-14 is the best choice for drought resistance in case of inner-Terai ecological belt of Nepal.

1. Rapeseed (Brassica napus) Varieties Performance under Soil Moisture Stressed and Non-stressed Condition in Terai Region of Nepal
WRJAS
Rapeseed (Brassica napus) Varieties Performance under
Soil Moisture Stressed and Non-stressed Condition in
Terai Region of Nepal
1Roshan Babu Ojha, 2Himal Prasad Timalsina, 3
Razan Malla
1Scientist, Soil Science Division, Nepal Agricultural Research Council, Nepal
2Senior Scientist, National Wheat Research Program, Nepal Agricultural Research Council, Nepal
3Technical Officer (soil science), Oilseed Research Program, Nepal Agricultural Research Council, Nepal
Soil moisture is limiting factor of production during rapeseed growing period of Nepal. An
experiment was conducted in research farm of oilseed research program (ORP), Sarlahi, Nepal in
order to evaluate the performance of elven pipeline varieties of rapeseed under soil moisture
stress condition. They were laid out in the randomized complete block design with three
replications for two years 2014 to 2016. Separate field blocks for irrigated (non-stress) and
drought (stressed) condition were made. Yield from moisture stress (Ys) and non-stress (Ys) were
recorded to calculate different drought indices. Variety ICT 2010-3 performs better with the
highest tolerance index (TOL), marginal productivity (MP), gross mean productivity (GMP), yield
index (YI), yield stability index (YSI), stress tolerance index (STI) and the lowest stress
susceptibility index (SSI) and percentage yield reduction (%YR). But in the second-year variety
ICT 2001-14 has the highest MP, GMP, YI and STI. Variety ICT 2001-19 has the highest TOL and
YSI, and the lowest SSI and %YR. On an average ICT 2001-14 has the highest MP, GMP and STI
and these indices are significantly positively correlated with stressed and non-stressed yield. So,
ICT 2001-14 is the best choice for drought resistance in case of inner-Terai ecological belt of
Nepal.
Key Words: Drought indices, Drought resistance, Non-Stressed yield, Stressed yield, Rapeseed.
INTRODUCTION
Rapeseed (Brassica napus) is a popular oilseed crops of
Terai, inner-Terai and upland mid-hills of Nepal where
moisture is always a limiting factor of crop production.
Nepal is in subtropical climatic zones. It receives heavy
monsoon rainfall during June-July and less winter rainfall
during November-December. So, there is moisture stress
during rapeseed growing period (winter). There are two
critical stages of moisture in rapeseed, first is at vegetative
stage and next is at flowering stage. Winter rainfall is not
sufficient to supply enough moisture during this stage and
winter rainfall may not coincide these two growing stage of
rapeseed. Soil moisture stress during reproductive period
is more sensitive than vegetative stage (Ahmadi and
Bahrani, 2009). Various factors like weather conditions,
rapeseed developmental stages, stress intensity and
duration, and crop genotype determines the effect of
stress on crop plant (Robertson and Holland, 2004). So,
rapeseed yield gap between research farm and farmer
field is very high. So, best rapeseed variety under soil
moisture stress condition is necessary to identify.
Drought indices are important agronomic practice to select
drought tolerant varieties despite genetic improvement
(Richards et al., 2002).
*Corresponding Author: Roshan Babu Ojha, Scientist,
Soil Science Division, Nepal Agricultural Research
Council, Nepal. E-mail: roshanbachhan@gmail.com
World Research Journal of Agricultural Sciences
Vol. 4(1), pp. 120-125, July, 2017. ©www.premierpublishers.org.ISSN: XXXX-XXXX
Research article

2. Rapeseed (Brassica napus) Varieties Performance under Soil Moisture Stressed and Non-stressed Condition in Terai Region of Nepal
Ojha et al. 121
So, drought indices are used to determine the yield loss
under moisture stressed (drought) condition compared to
non-stressed (irrigated) condition. This index provides the
basis to select drought resistant varieties (Mitra, 2001).
Various drought indices have been proposed on the basis
of empirical findings (Sio-Se Mardeh et al., 2006; Shirani
Rad and Abbasian, 2011). Stress susceptibility index (SSI)
indicate the susceptibility of the variety to yield loss during
soil moisture stress condition (Fischer and Maurer, 1978).
Stress tolerance index (STI) in the other hand is helpful to
identify the varieties that have higher productivity under
moisture stress and non-stress condition (Fernandez,
1992). Further, Farshadfar and Sutka (2002) proposed a
modified stress tolerance index (MSTI) in which a separate
correction coefficient is calculated and multiplied to STI.
Percent reduction in the yield is another important
parameter of drought indices which gives how much yield
has been reduced at stressed condition compared to non-
stressed condition (Choukan et al., 2006). The main
objective of this study is to select the drought tolerant
variety of rapeseed at inner Terai ecological belt of Nepal.
MATERIALS AND METHODS
A field trial was conducted at research farm of oilseed
research program (ORP), Nawalpur, Sarlahi during 2014
to 2016. The soil of research farm is sandy loam with very
acidic (5.1) soil reaction, medium organic matter content
(3.2), medium to high available phosphorous (26 kg/ha),
high potassium (198 kg/ha) and medium nitrogen content
(0.12%) (SSD, 2015). Eleven different pipeline varieties of
rapeseed (Goldee Tori, ICT 2003-15, ICT 2001-14, ICT
2006-4, ICT 2001-19, ICT 2001-12, ICT 2010-3, ICT 2002-
8, ICT 2002-25, Preeti (check variety) and Uttara) have
been selected as treatments. They were arranged in
randomized complete block design in three replications.
Variety Preeti was chosen as the standard check variety
because it already a released variety by ORP and the most
cultivated variety of the region. Two separate field plots,
25 m apart, for irrigated (non-stressed) and non-irrigated
(stressed) were made in order to avoid water entering into
non-irrigated plot. However, winter rainfall is very minimum
which did not affect the soil moisture level. Two irrigations
were given to meet the crop water requirement of the
rapeseed in irrigated plot once at active vegetative stage
and next at reproductive stage (critical stage) up to the field
capacity level by surface flooding method. Except
irrigation, all other activities and treatments were same for
irrigated and non-irrigated plots.
Each experimental plot consisted seven rows with 2m x
5m area. The row to row spacing is 30 cm and plant to
plant spacing is continuous. Later manual thinning
maintained approximately 10 cm plant to plant spacing.
Seed yield of irrigated plot (Yp) and non-irrigated plot (Ys)
was recorded after the final harvest of both years,
February, 2015 and 2016. After then drought resistance
indices were calculated based on the following formulas:
SN Drought index Formula Cited from
a Tolerance Index
(TOL)
Yp – Ys Rosielle and
Hamblin 1981;
Hossain, 1990
b Marginal
Productivity (MP)
(Ys+Yp)/2 Rosielle and
Hamblin, 1981;
Hossain et al., 1990
c Geometric Mean
Productivity (GMP)
√(Yp x Ys) Fernandez, 1992
d Stress
Susceptibility
Index (SSI)
[1 – (Ys/Yp)] /
[1 – (Ŷs/Ŷp)]
Fisher and Maurer,
1978
e Stress Tolerance
Index (STI)
(Yp x Ys) / Ŷp Fernandez, 1992
f Yield Index (YI) Ys/ Ŷs Lin et al., 1986
g Yield Stability
Index (YSI)
Ys/Yp Bouslama and
Schapaugh, 1984
h Percent Yield
Reduction (%YR)
(Yp-Ys)/Yp x
100
Choukan et al.,
2006
Where, Ys is the yield at stressed condition, Yp is the yield at
non-stressed condition, Ŷs and Ŷp are average yield at
stressed and non-stressed condition respectively.
Data were analyzed by using GenStat software. Means
were separated by Tukey’s test at 5% level of significance.
Sigma plot version 10 was used for graphics. Wilkinson
Test of normality was done. All data was found normal
distribution and normal data were subjected to ANOVA
analysis.
RESULTS AND DISCUSSIONS
Except the varieties ICT 2003-15 and ICT 2001-19 other
varieties yielded more than standard check variety in
irrigated condition in 2016. However, in stressed condition
only three varieties viz. ICT 2001-14, ICT-2010-3 and
Uttara yielded more than standard check variety (Figure
2). Similarly, in first year variety ICT 2010-3 yielded the
highest followed by ICT-2001-14, ICT 2003-15 and Goldee
Tori in stressed condition (Figure 1b).
Comparing yield only with the standard check might be
misleading during selecting the drought tolerant varieties.
So, various drought indices are calculated.
In the first year, tolerance index of ICT 2001-12 was found
the highest. Similarly, the highest marginal productivity
was obtained from ICT 2001-19 with the least yield
reduction from Goldee Tori. Rest of all drought indices viz.
Gross mean productivity, yield stability index, yield index
and stress tolerance index was found highest from variety
ICT 2010-3 with the least stress susceptibility index.
However, in second year variety ICT 2001-14 has the
highest marginal productivity, gross marginal productivity,
yield index and stress tolerable index (Table 2). Marginal
productivity, Gross marginal productivity, yield index and
stress tolerance index indicate the efficiency of the variety.
There exist highly significant positive correlation between
these indices (Table 3).

3. Rapeseed (Brassica napus) Varieties Performance under Soil Moisture Stressed and Non-stressed Condition in Terai Region of Nepal
World Res. J. Agric. Sci. 122
Figure 1: Boxplot showing the yield of rapeseed at non-stressed (figure 1a) and stressed condition (figure 1b), 2015. Numbers 1, 2,
3,..... , 11 in x-axis represent the varieties entry number (refer Table 1 for their respective varieties).
Table 1: Drought tolerance indices of different rapeseed varieties at ORP, Nawalpur, in 2015
Entry No. Varieties TOL MP SSI GMP %YR YI YSI STI
1 Goldee tori 123.58 458.69 0.69 454.51 21.45 1.05 0.76 0.62
2 ICT 2003 – 15 213.76 493.21 1.03 481.49 37.09 1.02 0.64 0.70
3 ICT 2001 – 14 187.60 506.85 0.90 498.09 32.55 1.10 0.69 0.75
4 ICT 2006 – 4 250.50 495.99 1.17 479.92 43.47 0.98 0.60 0.69
5 ICT 2001 – 19 255.51 513.53 1.15 497.38 44.34 1.02 0.60 0.74
6 ICT 2001 – 12 296.15 490.42 1.34 467.54 51.39 0.91 0.54 0.66
7 ICT 2010 – 3 139.72 534.12 0.67 529.53 24.25 1.23 0.77 0.84
8 ICT 2002 – 8 188.71 473.45 0.96 463.95 32.75 1.01 0.67 0.65
9 ICT 2002 – 25 280.56 509.35 1.25 489.65 48.69 0.98 0.57 0.72
10 Uttara 221.55 451.46 1.14 437.65 38.45 0.90 0.61 0.58
11 Preeti 33.00 316.50 0.29 316.07 5.73 0.80 0.90 0.30
TOL = Tolerence Index; MP = Marginal Productivity; SSI = Stress susceptibility Index; GMP = Gross Mean
productivity; %YR = percentage in yield reduction; YI = Yield index; YSI = Yield stability index and STI =
Stress tolerance index
Table 2: Drought tolerance indices of different rapeseed varieties at ORP, Nawalpur, in 2016
Entry No. Varieties TOL MP SSI GMP %YR YI YSI STI
1 Goldee tori 144.30 332.75 1.53 324.83 40.31 0.95 0.64 0.82
2 ICT 2003 – 15 20.30 267.75 0.31 267.56 5.67 0.94 0.93 0.56
3 ICT 2001 – 14 29.60 400.30 0.31 400.03 8.27 1.40 0.93 1.25
4 ICT 2006 – 4 170.40 260.00 2.12 245.64 47.60 0.64 0.51 0.47
5 ICT 2001 – 19 2.40 242.40 0.04 242.40 0.67 0.88 0.99 0.46
6 ICT 2001 – 12 106.50 299.55 1.30 294.78 29.75 0.90 0.70 0.68
7 ICT 2010 – 3 32.50 393.85 0.34 393.51 9.08 1.38 0.92 1.21
8 ICT 2002 – 8 173.60 329.00 1.79 317.34 48.50 0.88 0.58 0.79
9 ICT 2002 – 25 161.80 286.50 1.89 274.84 45.20 0.75 0.56 0.59
10 Uttara 47.30 354.55 0.54 353.76 13.21 1.21 0.87 0.98
11 Preeti 28.50 312.25 0.37 311.92 7.96 1.09 0.91 0.76
TOL = Tolerence Index; MP = Marginal Productivity; SSI = Stress susceptibility Index; GMP = Gross Mean
productivity; %YR = percentage in yield reduction; YI = Yield index; YSI = Yield stability index and STI =
Stress tolerance index
The highest tolerance index and yield stability index was
obtained from variety ICT 2001-19. Similarly, the lowest
stress susceptibility index and percentage yield reduction
was also obtained from variety ICT 2001-19. Tolerance
index, yield stability index, stress susceptibility index and
percentage yield reduction are consistency parameters for
Figure: 1a Figure: 1b

4. Rapeseed (Brassica napus) Varieties Performance under Soil Moisture Stressed and Non-stressed Condition in Terai Region of Nepal
Ojha et al. 123
Table 3: Simple correlation coefficient of different drought indices with yield of 11 varieties of rapeseed
Variables Ys Yp TOL MP SSI GMP YR YI YSI STI
Ys 1 .406ns -.642*
.865**
-.690*
.909**
-.642*
1.000**
.688*
.920**
Yp 1 .441ns .809**
.374ns .749**
.441ns .403ns -.379ns .728*
TOL 1 -.170ns .992**
-.265ns 1.000**
-.644*
-.993**
-.293ns
MP 1 -.238ns .995**
-.170ns .863**
.234ns .991**
SSI 1 -.331ns .992**
-.692*
-1.000**
-.356ns
GMP 1 -.265ns .908**
.327ns .997**
YR 1 -.644*
-.993**
-.293ns
YI 1 .689*
.919**
YSI 1 .352ns
STI 1
Ys = yield at stressed condition, Yp = yield at non-stressed condtion, TOL = Tolerence Index; MP = Marginal Productivity; SSI = Stress
susceptibility Index; GMP = Gross Mean productivity; %YR = percentage in yield reduction; YI = Yield index; YSI = Yield stability index, STI
= Stress tolerance index, * = significant at P<0.05, ** = significant at P < 0.01 and ns = non-significant
Figure 2: Boxplot showing the yield of rapeseed at non-stressed (figure 2a) and stressed condition (figure 2b), in 2016. Numbers 1,
2, 3,..... , 11 in x-axis represent the varieties entry number.
selecting variety against drought. There also exists a
perfect positive significant correlation between tolerance
index, percentage yield reduction and stress susceptibility
index (Table 3). It indicate the variety ICT 2001-19 is more
consistence and stable than other variety. The correlation
between the yield indices also follow the normal trend.
In mean of two year variety ICT 2001-14 is superior in
marginal productivity, gross marginal productivity, yield
index and stress susceptibility index. Similarly, variety ICT
2001-19 is superior in tolerance index, yield stability index,
stress susceptibility index and percentage yield reduction
(figure 3a and 3b) but considering yearly mean variety ICT
2010-3 shows both consistent and stable character in first
year which is not observed in second year.
A significant positive correlation found between non-stress
yields (Yp) and MP, GMP, YI and STI (Golabadi et al.,
2006; Shirani Rad and Abbasian, 2011) similar with our
findings. So, these indices are good indicator of drought
tolerant rather other indices. Drought tolerant cultivar must
have index partly high correlation with grain yield under
stress and non-stress condition (Farshadfar et al., 2001).
There are various research paper with similar conclusion
in different crops like Golabadi et al. (2006) in wheat,
Farshadfar and Sukta (2002) in maize and Fernandez
(1992) in mungbean. During selection of appropriate
drought severity index, the correlation between the yield
under stressed and non-stressed condition and several
drought indices should be taken into consideration. Shirani
Rad and STI, GMP and MP are best indicator to select
variety that produce high yield both under stressed and
non-stressed environment (Abbasian, 2011; Shafazadeh
et al., 2004).
Figure: 2a Figure: 2b

5. Rapeseed (Brassica napus) Varieties Performance under Soil Moisture Stressed and Non-stressed Condition in Terai Region of Nepal
World Res. J. Agric. Sci. 124
Figure: 3a
Figure: 3b
Figure 3: Two years average mean relationship between Ys, Yp and drought indices (figure 3a and 3b) of eleven
pipeline varieties of rapeseed. The values of Ys, Yp and drought indices are two year mean values.
Under moderate stress condition MP, GMP and STI were
best indices for selecting drought tolerant varieties (Sio-Se
Mardeh et al., 2006). But under very severe stress none of
indices are useful in selecting drought tolerant cultivars
(Shirani Rad and Abbasian, 2011). However, Anwar et al.
(2011) found significant positive correlation of Yp with MP,
GMP andSTI and Ys with MP, GMP, STI, YI, TOL, SSI and
YSI. So, they concluded all drought indices other than
TOL, SSI and YSI are better indicator for selecting drought
resistant varieties. Significant positive correlation of Yp
with MP, GMP and STI and Ys with MP, GMP, YI, YSI and
STI (Table 3) was found. Hence, MP, GMP and STI are
better predictor of potential yield under stress and non-
stress condition.
CONCLUSION
Among different drought indices marginal productivity,
geometric mean productivity and stress tolerance indices
are selective indices in our study to identify the stress
tolerant rapeseed varieties. In the first year, variety ICT
2010-3 has the highest MP, GMP and STI. However, in the
second year and two year average value, variety ICT
0
100
200
300
400
500
Goldee tori
ICT 2003 - 15
ICT 2001 – 14
ICT 2006 - 4
ICT 2001 – 19
ICT 2001 – 12ICT 2010 – 3
ICT 2002 – 8
ICT 2002 – 25
Uttara
Preeti
Ys Yp TOL MP GMP %YR
0.00
0.50
1.00
1.50
2.00
2.50
Goldee tori
ICT 2003 - 15
ICT 2001 – 14
ICT 2006 - 4
ICT 2001 – 19
ICT 2001 – 12ICT 2010 – 3
ICT 2002 – 8
ICT 2002 – 25
Uttara
Preeti
SSI YI YSI STI

6. Rapeseed (Brassica napus) Varieties Performance under Soil Moisture Stressed and Non-stressed Condition in Terai Region of Nepal
Ojha et al. 125
2001-14 showed the highest MP, GMP and STI in stressed
and non-stressed conditions. So, variety ICT 2001-14 is
recommended for drought prone (rainfed) area of inner
Terai ecological belt Nepal.
ACKNOWLEDGEMENT
Authors would like to thank Rajan Malla, technical officer
ORP; Mr. Kailash Pradad Bhurer, ex-chief, ORP; DK
Choudhary, senior scientist, ORP and entire team of ORP
for their valuable contribution during field work of this trial.
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Accepted 24 July, 2017.
Citation: Ojha RB, Timalsina HP, Malla R (2017).
Rapeseed (Brassica napus) Varieties Performance under
Soil Moisture Stressed and Non-stressed Condition in
Terai Region of Nepal. World Research Journal of
Agricultural Sciences, 4(1): 120-125.
Copyright: © 2017 Ojha et al. This is an open-access
article distributed under the terms of the Creative
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use, distribution, and reproduction in any medium,
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