Abstract:
The principal objectives of the present investigation were to assess inter- cultivar
variation for salt tolerance in safflower, draw relationships of various physiological and
biochemical attributes to salt tolerance of safflower, identify selection criteria for further
improvement in salt tolerance of safflower through specific breeding programs and to
appraise whether or not salt stress alters the composition and quality of safflower oil.
Different experiments were carried out to assess variation in salt tolerance in 10
accessions (Safflower-31, Safflower-32, Safflower-33, Safflower-34, Safflower-35,
Safflower-36, Safflower-37, Safflower-38, Safflower-39, Safflower-78) of safflower
(Carthamus tinctorius L.) at varying levels of salt (NaCl) at different growth stages,
germination, seedling and adult stages. The results of the germination experiment showed
that salt stress had an inhibitory effect on germination percentage and seedling biomass
of all 10 accessions. A significant variation in the accessions was observed at the two
higher salt levels (180 and 240 mM). While ranking the accessions on the basis of their
potential for germination and producing seedling biomass at 240 mM NaCl, lines
Safflower- 31 and Safflower-35 were found to be tolerant, Safflower-33, Safflower-37,
Safflower-38 and Safflower-78 salt sensitive, and Safflower-32, Safflower- 34,
Safflower-36 and Safflower-39 moderately tolerant. To further evaluate safflower lines
for their performance at later growth stages, an experiment was conducted using two salt
levels (0 control, 150 mM NaCl). Salt stress caused a marked reduction in biomass
production, photosynthetic pigments, leaf water relations, gas exchange characteristics,
proline content, mineral nutrients, activities of some key antioxidant enzymes, different
fatty acids, tocopherol contents and yield attributes. A significant inter-cultivar variation
was found in the set of 10 diverse safflower accessions at the adult stage. Although
variation for salt tolerance was found at all growth stages, that found at the germination
and seedling stage was not maintained at the vegetative or adult growth stages. On the
basis of shoot biomass production at the vegetative stage, accession Safflower-37 was
ranked as tolerant, while Safflower-31, Safflower-32, Safflower-34, Safflower-39, and
Safflower-78 as salt sensitive. In contrast, in terms of seed yield, accessions Safflower-
32, Safflower-34, and Safflower-39 were ranked as tolerant, while Safflower-31,
Safflower-33, Safflower-35, Safflower-36, and Safflower-38 as salt sensitive. A positiveassociation of net photosynthetic rate (A) with growth and seed yield was observed in the
10 diverse safflower lines under saline conditions, and thus it could be used as an
effective
selection
criterion
for
salinity
2
tolerance
in
safflower.