沙漠研究 24-1, 169-174 (2014)
Ἃ₍◊✲ 24-1, 169 - 174 (2014)
Journal of Arid Land Studies
Journal of Arid Land Studies－ DT11 Refereed Paper －㸫DT11 Refereed Paper㸫

Physiological Response of Diverse Origin
Spring Safflower Genotypes to Salinity
Sukhbir SINGH1), Kulbhushan GROVER1), Sultan BEGNA1), Sangu ANGADI*1),
Manoj SHUKLA1), Robert STEINER1) and Dick AULD2)
Abstract: Increased salinity of irrigation water is a major constraint affecting crop productivity in the Southern High Plains ofUnited States of America. Adapting salt tolerant crops could be a viable option for the region. Yield formation and physiology ofdiverse spring safflower (Carthamus tinctorius L.) genotypes was studied under a range of salinity levels in a greenhouse experiment.
Five irrigation salinity levels of 0.5 (control), 2.5, 5.0, 7.5 and 10 dS m-1 along with five genotypes of diverse origin were arranged in arandomized complete block design with four replications. Seeds per head and harvest index were the most sensitive parameters tosalinity, declining 98% and 99% at 10 dS m-1 compared to control, respectively. In contrast, biomass per plant and 1000-seed weight
were reduced only 43% and 56% with the same 10 dS m-1. Plant height and head numbers were only affected at the highest salinity
level (10 dS m-1). Increasing salinity levels decreased relative water content (RWC), leaf water potential (Ȍ1), osmotic potential atfull turgor (Ȍʌ100), photosynthesis and transpiration. However, chlorophyll fluorescence was unaffected by salinity treatments. Salt
tolerance of PI199898, among all the genotypes, was manifested by higher 1000-seed weight and Harvest Index (HI); this tolerance
was associated with its ability to maintain higher Ȍ1, osmotic concentration, RWC, photosynthesis and transpiration. Safflower canbe planted under moderate salinity levels of < 5 dS m-1.
Key Words: Photosynthesis, Safflower, Salinity, Water potential, Yield formation

1. Introduction
Salinity is one of the major abiotic stresses affecting
agricultural productivity, particularly in arid and semi-arid
regions of the world including the Southern High Plains ofUnited States of America. Globally, about half of the irrigatedland or 20% of the cultivated land or 7% of the total land area
is affected by salinity (Sudhir and Murthy, 2004). Saline
irrigation water, high evaporation, and low rainfall are thecontributing factors to salinity problems in New Mexico andWest Texas. Adverse effects of salinity on plant growth anddevelopment are mainly due to osmotic stress, salt stress,
nutritional imbalance, and sometimes a combination of thesefactors (Ashraf, 1994). Salinity also restricts the supply ofphotosynthetic assimilates to growing tissues (Munns, 1993).
These adverse effects of salinity have made agriculture lesseconomical for farmers as low yields or sometimes complete
crop failures are quite common under saline conditions.
Hence, in the Southern High Plains where salinity is higher forsensitive crops, inclusion of salt tolerant crops in crop rotation
could be a viable alternative.
Safflower is generally considered as a moderately salt
tolerant crop and is grown in arid and semi-arid regions of the* Corresponding Author: angadis@ad.nmsu.edu

world where salinity can restrict the growth of many othercrops (Bassil and Kaffka, 2002). However genotypicvariation for salt tolerance has been reported in safflower in the
Middle East (Yeilaghi et al., 2012). Hence, a better
understanding of physiological aspects of salinity stress
tolerance mechanisms will not only help in identifying awell-adapted, salinity tolerant germplasm for the SouthernHigh Plains but also help breeders to use genes involved in salt
stress tolerance for crop improvement in saline conditions.
The objective of the current study was to assess physiologicaland yield formation responses of diverse spring safflower
genotypes collected from different geographic locations underrange of salinity levels.

2. Materials and Methods
2.1. Experimental site description
A greenhouse experiment was conducted at theAgricultural Science Center (ASC) of New Mexico State
University, located 23 km north of Clovis, New Mexico(34°35’N, 103°12’ W) at an altitude of 1348 m above sea level.
The study location is characterized as semi-arid climate withannual average precipitation of 445 mm, and the mean
maximum and minimum temperatures of 22°C and 7°C,
㸦Received, September 16th, 2013; Accepted, December 23rd, 2013㸧

2346 State Road 288, Clovis, NM 88101-9998
1) New Mexico State University, Las Cruces, NM

2) Texas Tech University, Lubbock, TX

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respectively (Contreras-Govea et al., 2011). The average airtemperature in the greenhouse during the whole experimentperiod was maintained at 30°C during day and 24°C at night.
The sunlit greenhouse used for the study transmitted most of
the sunlight, and mid-day light intensities were 1500 µmol m-2
sec-1. Sandy loam soil was used in the plastic pots of 15 kg
capacity. The bulk density and electrical conductivity (EC) of
the soil were 1.34 g cm-3 and 1.2 dS m-1, respectively.
2.2. Planting and experimental design
Five safflower genotypes PI199898, PI248866, PI304453,
PI304507, and S333 were collected from National Plant
Germplasm System (NPGS), Pullman, WA, USA. These
genotypes originated in different countries (India, Iran, Turkey
and United States). Before planting, pots were watered tofield capacity with domestic well water (§ 0.5 dS m-1). Fourseeds were planted on 21st March, 2012 in the middle of eachpot. After establishment, thinning was done to maintain twoplants per pot. Salinity treatments were imposed from 8th
May, 2012 to 30th June, 2012. Salt solutions were preparedby adding a calculated amount of NaCl per liter of domestic
well water. Five salinity levels of 0.5 (control), 2.5, 5.0, 7.5
and 10 dS m-1 were prepared. Salt solutions were applied
manually and EC was determined by an EC meter (Model
Orion Star A215, Thermo Scientific, Singapore). All pots
were maintained above 60% available water by frequent
weighing to avoid water stress to the plants. The experiment
was laid out in a Randomized Complete Block Design withfour replications.
2.3. Physiological measurements
All the physiological observations were recorded during
midday and pots were divided into two sets to complete
observations in four days. First set comprised of all fivegenotypes irrigated with two extreme salinity levels of 0.5 dS
m-1 (control) and 10 dS m-1. The second set included two
genotypes (PI304507 and PI248866), irrigated with all thesalinity levels (0.5, 2.5, 5.0, 7.5 and 10 dS m-1). Observations
were taken at 62 days after planting when salinity stress started
affecting plants.
Photosynthesis measurements were recorded using a
portable photosynthesis system (Model LI-COR 6400, Lincoln,
NE, USA) selecting the two youngest, fully expanded andilluminated leaves, one from each plant in the pot.
Chlorophyll fluorescence was measured simultaneously withphotosynthesis measurements. The ratio of variable tomaximal fluorescence (Fv/Fm) was measured after dark
adapting two leaves per pot for 30 minutes using a continuous
source fluorometer (Model OS 30p, Opti-Science, Hudson,
NH, USA).

Relative water content of two leaves per pot was measured
using the following equation Relative Water Content = (Freshweight - Dry weight / Turgid weight - Dry weight) × 100 (Eq.
1).
Pressure bomb (Model 615, PMS instrument company,
Albany, OR, USA) was used to measure leaf water potential(Ȍ1) (Turner, 1981) on two young branches per pot. At thesame time, two leaf samples were collected, frozen and later
thawed to measure leaf osmotic potential (Ȍʌ) of the expressed
sap using a pre-calibrated Wescor Vapor Pressure Osmometer(Model Wescor 5520, Logan, UT, USA). Relative watercontent was used to convert osmotic potential (Ȍʌ) to osmotic
potential at full turgor (Ȍʌ100) using the following formulaȌʌ100 = (Ȍʌ x RWC)/100 (Eq. 2).
2.4. Agronomic measurements
Plant height from the soil surface to tip of two plants wasmeasured at the end of the growing period. Both plants werehand harvested and oven dried at a temperature of 55°C for 3
days to measure the shoot dry weight. Data on number ofheads, number of seeds and seed weight was recorded and1000-seed weight was calculated. Harvest index wascomputed as the ratio of seed yield to the total dry matter yield(Eq. 3).
The analysis of variance was performed on all the datausing proc GLM procedure of SAS software (Version 9.2, SAS
Institute, Inc., NC, USA). The means were separated using
LSD at 5% significance level (P ‫ ޒ‬0.05).

3. Results
3.1. Effect of salt stress on safflower physiology
A significant salt stress effect was observed on safflower
leaf water relation characteristics (Ȍ1, Ȍʌ100 and RWC),
photosynthesis, transpiration and fluorescence (Tables 1 and 2)
as the salinity level increased from control (0.5 dS m-1) to 10
dS m-1.
Genotypes did not show any significant differences for
RWC when averaged across the salinity treatments (Tables 1
and 2). Average RWC for all safflower genotypes under low
salinity was 80.3%, which decreased to 69.9% at 10 dS m-1(Table 1). Mean RWC of two genotypes decreased with anincrease in salinity level (Table 2). The highest RWC wasobserved in the control which was not significantly different
than 2.5 and 5 dS m-1 salinity levels. The lowest RWC wasobserved when salinity increased above 7 dS m-1.
Genotypes differed significantly for Ȍ1 across salinity
levels (Tables 1 and 2). PI304507 was the most stressed inboth observations, while PI199898 was the least stressed
genotype across two extreme salinity levels. The mean Ȍ1 of

171

PI304453
PI304453
S333
S333
PI304507
PI304507
PI248866
PI248866
PI199898
PI199898
Salinity
Salinity

Ȍ
Ψ111

Ȍ
Ψʌ100
π100
π100

RWC
RWC

Pn
Pn

(MPa)
(MPa)

(MPa)
(MPa)

(%)
(%)

(µmol
(µmol m
m-2-2-2 sec
sec-1-1-1))†-1.50ab-1.50ab††-1.50ab-1.50ab-1.54b
-1.54b
-1.41ab-1.41ab-1.36a-1.36a-0.95a-0.95a-1.07ab-1.07ab-1.08ab-1.08ab-1.21b
-1.21b
-1.23b
-1.23b

71.6a
71.6a
74.4a
74.4a
76.0a
76.0a
75.3a
75.3a
78.2a
78.2a

23.8a
23.8a
18.7a
18.7a
20.4a
20.4a
20.7a
20.7a
23.5a
23.5a

Tr
Tr
(mmol
(mmol m
m-2-2-2
sec
sec-1-1-1))

13.7ab
13.7ab11.2b
11.2b
13.1ab
13.1ab
14.1ab
14.1ab
15.4a
15.4a

Fv/Fm
Fv/Fm

-1
-1
-1

(dS
(dSm
m ))
0.5
0.5
10
10
G
G xxSS-1.15a-1.15a-1.77b
-1.77b
NSNS-0.97a-0.97a-1.23b
-1.23b
NS
NS

80.3a
80.3a
69.9b
69.9b
NS
NS

23.1a
23.1a
19.7a
19.7a
NS
NS

15.7a
15.7a
11.3b
11.3b
NS
NS

0.800a0.800a0.809a0.809aNSNS͊ Values within each column followed by same letter are notsignificantly different at P0.05.
NS= Non-significant at P0.05.
Table 2. Effect of salinity levels on water potential (Ȍ1), osmotic
potential at full turgor (Ȍʌ100), relative water content(RWC), photosynthesis (Pn), transpiration (Tr) andfluorescence (Fv/Fm) of two safflower genotypes in 2012 at
Clovis, NM.

95

a

a

85

b

75

c

65

d

55
45
35

0.775c0.775c0.798b0.798b
0.813ab
0.813ab0.824a0.824a0.813ab
0.813ab

PI304453

S333

PI304507 PI248866 PI199898
Genotype

85
Plant height (cm)Ge
Genotype
notype105
Plant height (cm)

Table 1. Effect of salinity levels on water potential (Ȍ1), osmotic
potential at full turgor (Ȍʌ100), relative water content(RWC), photosynthesis (Pn), transpiration (Tr) andfluorescence (Fv/Fm) of five safflower genotypes in 2012 at
Clovis, NM.

a

a

a

2.5

5

75

a

b

7.5

10

65
55
45
35
0.5

-1
Salinity level (dS m )Fig. 1. Plant height of safflower genotypes as affected by different
salinity levels in 2012 at Clovis, NM. Bars with the same letterare not significantly different at P0.05.

͊ Values within each column followed by same letter are notsignificantly different at P0.05.
NS= Non-significant at P0.05.

above 5 dS m-1 (Table 2). Decrease in photosynthesis andtranspiration with increase in salinity is also observed in othercrops (Burman et al., 2003). Significant fluorescencedifferences were observed among the genotypes with
PI248866 showing the highest Fv/Fm (Tables 1 and 2).
However, the Fv/Fm was not affected by an increase in salinity(Table 2).
No significant genotype by salinity interactions wereobserved for RWC, Ȍ1, Ȍʌ100, photosynthesis, transpiration andfluorescence. This indicates that in spite of diverse origin,genotypes included in this study responded to salinity similarly.

two genotypes decreased with increasing salinity levels and thelowest Ȍ1 or the highest stress level was observed above 7.5 dS
m-1 salinity level (Table 2). Mean Ȍ1 values of five genotypes
also increased with higher salinity level (Table 1). An
increase in the solute accumulation was observed with thedecrease in Ȍ1 as the salinity level increased from control to 10
dS m-1 (Table 2). The lowest Ȍʌ100 was observed by
PI199898 across two extreme two salinity levels. Salt stressat the highest salinity level resulted in the lowest Ȍʌ100, which
was not significantly different from 7.5 dS m-1. The highestȌʌ100 was observed in the control.
No significant differences were noticed for photosynthesis
among genotypes (Tables 1 and 2). The average
photosynthesis for safflower ranged from 19.7 to 23.1 µmol
m-2 sec-1 for 10 dS m-1 and control, respectively (Table 1).
Although photosynthesis rate decreased with successive
salinity levels it was not statistically different at control, 2.5 and5 dS m-1 levels (Table 2). Transpiration variation among the
genotypes was also small (Tables 1 and 2). Decrease intranspiration with increasing salinity was significant only

3.2. Effect of salt stress on growth and yield
Plant height varied significantly among the genotypes.
Genotype PI304453 had the tallest plants with an averageheight of 93.4 cm, while genotype PI199898 had the shortest
plants with a height of 59.4 cm (Fig. 1). Only two safflower
genotypes PI304453 and S333 did not differ significantly inplant heights. Thus, genetic diversity for plant height among
the tested genotypes was large. The decrease in plant heightwith increase in salinity level was only significant at thehighest salinity level (10 dS m-1) and the interaction effect was
not significant.
Genotype S333 produced the highest number of heads perplant while the lowest was observed in PI304507 (Table 3).
Genotypes PI248866, PI304453 and PI199898 did not differ
for number of heads per plant, but differed significantly fromthe highest and the lowest head producing genotypes. A
significant decrease in number of heads per plant was observed
only above 7.5 dS m-1 salinity level with the lowest number
recorded at 10 dS m-1.
Number of seeds per head was affected by genotype,

Salinity
Salinitylevelevell(dS(dS m
m-1-1-1))

0.5
0.5
2.5
2.5
55
7.5
7.5
10
10

Ȍ
Ψ111

Ȍ
Ψʌ100
π100
π100

RWC
RWC

Pn
Pn
(µmol
(µmol m
m-2-2-2
sesecc-1-1-1))

Tr
Tr
(mmol
(mmol m
m-2-2-2
sec
sec-1-1-1))

(MPa)
(MPa)

(MPa)
(MPa)

(%)
(%)

†††

Fv/Fm
Fv/Fm

-1.13a-1.13a-1.38b
-1.38b-1.70c-1.70c-1.96d
-1.96d
-2.03d
-2.03d-1.07a-1.07a-1.24ab-1.24ab-1.26ab-1.26ab-1.41b
-1.41b
-1.44b
-1.44b86.6a
86.6a
80.3ab80.3ab
75.8ab
75.8ab
72.5b
72.5b
72.2b
72.2b

27.7a
27.7a
26.1ab26.1ab
23.6abc
23.6abc
22.9bc22.9bc
20.6c
20.6c

17.8a
17.8a
16.3ab
16.3ab
17.5a
17.5a
14.9b
14.9b
15.3b
15.3b

0.819a0.819a0.815a0.815a0.813a0.813a0.812a0.812a0.821a0.821a-1.72b
-1.72b
-1.53a-1.53aNSNS-1.22a-1.22a-1.32a-1.32a
NS
NS

76.2a
76.2a
79.5a
79.5a
NS
NS

24.3a
24.3a
24.0a
24.0a
NS
NS

16.7a
16.7a
16.0a
16.0a
NS
NS

0.805b
0.805b
0.827a0.827aNS
NS

Genotype
Genotype
PI304507
PI304507
PI248866
PI248866
G
G xxSS

172

Table 3. Yield attributing characters of five safflower genotypes
under different salinity levels in 2012 at Clovis, NM.
Heads
Heads

Se
Seeds
eds

1000
1000 see
seedd

plant
plant-1-1

head
head-1-1

Wt
Wt (g)(g)

Plant
Plant-1-1 (g)
(g)

(%)
(%)

PI304453
PI304453
S333
S333
PI304507
PI304507

†
9.9b
9.9b†
11.0a
11.0a
7.7c
7.7c

13.7a
13.7a
8.9b
8.9b
9.4b
9.4b

26.7c
26.7c
28.8bc28.8bc33.9ab
33.9ab

30.1a
30.1a
27.5a
27.5a
20.3b
20.3b

12.3b
12.3b
10.0b
10.0b
12.3b
12.3b

PI248866
PI248866
PI199898
PI199898
Salinity
Salinity

9.8b
9.8b
9.1b
9.1b

7.0b
7.0b
9.1b
9.1b

34.8ab
34.8ab35.1a
35.1a

18.9bc18.9bc
16.9c
16.9c

13.9ab
13.9ab
16.8a
16.8a

9.6a
9.6a
10.1a
10.1a
10.3a
10.3a
9.6a
9.6a
7.9b
7.9b

19.3a
19.3a
19.3a
19.3a

27.3a
27.3a
28.4a
28.4a

7.0b
7.0b
2.2c
2.2c
0.3c
0.3c

46.9a
46.9a
35.7b
35.7b
25.9c
25.9c
23.8c
23.8c
20.5c
20.5c

22.9b
22.9b
19.5c
19.5c
15.6d
15.6d

29.6a
29.6a
23.6b
23.6b
9.3c
9.3c
2.5d
2.5d
0.3d
0.3d

NS
NS

**

NS
NS

**

NS
NS

Genotype
Genotype

-1
(dS
(dS m
m-1))
0.5
0.5
2.5
2.5
55
7.5
7.5
10
10

G
G xxSS

Biomass
BiomassHI
HI

͊ Values within each column followed by same letter are notsignificantly different at P0.05.
*, NS Significant and non-significant at P0.05, respectively.
PI-304453
S-333
PI-304507
PI-248866
PI-199898

Biomass (g pl-1)

40
35
30
25
20
15

B

30

Seeds head-1

25
20
15
10
5
0

A
0.0

2.5

5.0

7.5

10.0

Salinity level (dS m-1)

minimum 1000-seed weights, respectively. A rapid decreasein 1000-seed weight across all genotypes was noticed witheach stress level up to 5 dS m-1 and after that, decrease was
non-significant. The highest salinity level exhibited 56%
decrease in mean 1000-seed weight of all genotypes over thecontrol.
Genotype, salinity level and their interactions significantly
affected total aboveground biomass production (Table 3).
Averaged across salinity levels, genotype PI304453 produced
the highest biomass while PI199898 produced the lowest
biomass which was almost half of the former. Averaged overgenotypes, a significant reduction in biomass production wasobserved as the salinity level increased above 2.5 dS m-1 andthe lowest biomass production was recorded at 10 dS m-1
salinity level. Two higher biomass producing genotypes,
PI304453 and S333, showed rapid declines in biomass as
salinity increased above 2.5 dS m-1, while other threegenotypes did not differ in their biomass across salinity levels(Fig. 2B). Biomass of PI304453 was significantly higher
compared to the three lowest biomass producing genotypes up
to 5 dS m-1, but biomass production did not differ among
genotypes at salinity levels above 5 dS m-1.
Significant differences in biomass partitioning into seed or
HI were noticed with genotype and salinity (Table 3). Acrosssalinity levels, PI199898 recorded the highest HI, which wassignificantly higher compared to all other genotypes except
PI248866. A rapid decrease was noticed in average HI ofgenotypes with increase in salinity, particularly above 5 dS m-1,
which indicates the role of biomass partitioning on seed yieldat higher salinity levels.

Fig. 2. Interactions of safflower genotypes and salinity on (A) seeds
per head and (B) biomass production in 2012 at Clovis, NM.
Vertical bar is LSD at P0.05.

4. Discussion

salinity level and genotype x salinity interactions (Table 3).
In general, genotypes did not differ in the number of seeds perhead except for PI304453. Mean seeds per head did notchange up to 2.5 dS m-1 and started declining with further
increase in salinity. Number of seeds per head was a sensitive
parameter to salinity in this study. Among all the genotypes,
S333 recorded the highest number of seeds per head, however,decrease in seeds per head at 2.5 dS m-1 showed its sensitivity
to salinity (Fig. 2A). In the rest of safflower genotypes,
decline in seeds per head started after 2.5 dS m-1, whichindicated moderate salinity tolerance.
Negligible seedproduction was noticed under higher salinity levels (7.5 and 10
dS m-1) in all genotypes.
Effect of genotype and elevated soil salinity was observed
on 1000-seed weight (Table 3). PI199898 and PI304453,
averaged across salinity levels, showed the maximum and the

Negative effects of increasing salinity on Ȍ1 and RWC
were observed in this study. Reduction in RWC of safflower
plants with increase in salt content in soil was also reported by
Siddiqi and Ashraf (2008). Higher salt concentration in thesoil might be resisting the extraction of enough water tomaintain its water status. Decrease in Ȍ1 with increase insalinity was also observed, which is also supported by resultsof Bassil and Kaffka (2002). Decline in Ȍʌ100 under salt
stress conditions was observed in the present study. Soluteaccumulation or osmotic adjustments due to salinity in plant
cells is an important mechanism for salt tolerance of plants(Ashraf, 2004). The highest salt accumulation along withmaintenance of higher Ȍ1 in the PI199898 genotype suggests
its superior salt tolerance under salinity conditions among all
the genotypes.
Photosynthesis and transpiration of safflower genotypes
were only affected by salinity levels above 5 dS m-1. Even at

173

the highest salinity level used in this trial, photosynthesis andtranspiration decreased by 26% and 14%, respectively.
Reduction in stomatal and mesophyll conductance to CO2
diffusion of salt stressed leaves results in low CO2
concentration in the chloroplast which inhibits photosynthesis
under stress conditions (Delfine et al., 1999). Genotype
PI199898 maintained higher photosynthesis and transpiration
among all the genotypes. Maintenance of net photosynthesis
and stomatal conductance is related to salt tolerance (Lakshmi
et al., 1996). Salt stress could not affect the dark adapted
fluorescence in this experiment, which suggests that thephotochemistry of photosynthesis was not directly affected bysalt stress (Brugnoli and Lauteri, 1991).
Biomass production by safflower genotypes was stable up
to 2.5 dS m-1 and started declining gradually at higher salinity
levels. Reduced photosynthesis at higher salinity levels was
driving the decline in biomass production (Siddiqi et al., 2009).
At the highest salinity level used in this trial, biomass declinedby 43% compared to control which was similar to observationsof Bassil and Kaffka (2002). Interestingly, plant height was
stable across salinity levels except at 10 dS m-1, where it wassignificantly reduced by 7%. However, genetic variation wasobserved among genotypes for photosynthetic rate andbiomass production relationship. Pooled over salinity levels,
PI304453 recorded the highest photosynthesis rate andproduced the highest biomass under lower salinity levels. But,
it was also one of the more sensitive genotypes under higher
salinity levels. On the other hand, PI199898 had stablebiomass under a wide range of salinity levels.
Results showed that HI, an indicator of biomass
partitioning into seed, was sensitive to salinity in this trial.
PI199898 recorded the highest HI among genotypes. Lack ofgenotype by salinity interaction for the parameter suggested
that HI of all genotypes responded similarly. The HI at thehighest salinity level of 10 dS m-1 was reduced by 99%
compared to control, while biomass production reduced byonly 43%. Among the yield formation traits, averaged overgenotypes, heads per plant and 1000-seed weight wererelatively stable and recorded 18% and 56% reductions with 10
dS m-1 salinity over control. Feizi et al. (2010) reported
52.3% reduction in 1000-seed weight under high saltconditions (11.2 dS m-1) which is very similar to our findings.
Across salinity levels, PI199898 showed higher 1000-seedweight than other genotypes. Averaged across genotypes,
seeds per head reduced rapidly at higher salinity levels andrecorded 98% reduction with the highest salinity level.
Similar results were reported by Francois and Bernstein (1964).
Genotypes varied in their response and seeds per head declined
most rapidly in S333 at higher salinity levels, while it wasalmost stable in PI199898. Thus, in the current trial, sourceof photosynthate production was less affected by increased
salinity levels, while sink for photosynthate assimilation was
more affected. Among sink parameters, number of seeds andnot number of heads or inflorescence was more sensitive.
Considering agronomic data discussed above, PI199898
showed more salt tolerance due to higher HI, 1000-seed weight
and less fluctuation in biomass production under different
salinity levels than other genotypes. Head and seedproduction of PI199898 was also comparable with othergenotypes. This salt tolerance of PI199898 was associatedwith its ability to maintain higher Ȍ1, osmotic concentration,
RWC, photosynthesis and transpiration. It is thus apparent
that a combination of characters like higher osmotic adjustment,
higher water status leading to higher photosynthesis andtranspiration contribute to salinity tolerance of safflower
genotypes. Further assessment of PI199898 is needed toassess the salinity response in depth and potential to use it indeveloping commercial cultivars.
Acknowledgement
Financial support for the research from South Central Sun
Grant Program and from Agricultural Experiment Station of
New Mexico State University is acknowledged. Technicalsupport from Aaron Scott, Maria Nunez, Miguel Nunez, Eldon
Hays and Steve Brumfield is also much appreciated.

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