Abstract:
Canopy temperature (CT) is used as a selection tool
to improve crop adaptation to
drought. The aim of this work was to investigate as
sociation of some photosynthetic
characters with
CT
during grain filling in three cereal species. For
this objective, a two-
year study (2009-2011) was carried out in Kurdistan
Province in western Iran. Four
genotypes of triticale, three cultivars of bread wh
eat, and a new variety of barley were
compared under well watered (WW,
Ψ
soil water
= -3 bar) and deficit water (DW
,
Ψ
soil water
= -
12 bar) conditions in a randomized complete block d
esign (RCBD) with a split-plot
arrangement. Compared with well-watered plants, wat
er stressed plants displayed 1.44°C
higher canopy temperature irrespective of plant spe
cies. Under water stress condition, the
high yielding genotypes had lower canopy temperatur
e than low yielding ones by 1.23°C.
Results showed that under water deficit condition t
riticale relative to commercial cultivar
of wheat and barley had a higher adaptability to dr
ought as indicated by its higher yield
(59.5 g m
-2
more than average) and lower
CT
(0.28°C lower than average). The main
physiological traits correlated with canopy tempera
ture under DW treatment were
stomatal conductance (g
s
) (r= -0.73*), photosynthetic rate (P
n
) (r= -0.76*), the maximal
quantum yield of primary photochemistry (F
v
/F
m
) (r= - 0.71*), chlorophyll content at
grain filling (r= -0.72*) and leaf temperature (LT)
(r= 0.82**). Thus, canopy temperature
seems to play an important role in the physiologica
l basis of grain yield in different cereal
species, and can be used as a selection tool in bre
eding programs under water deficit
condition in Iran.
Keywords:
Barley, Chlorophyll fluorescence, Drought stress,
Net photosynthetic rate, Triticale.
