Evaluation of drought tolerance in rapeseed varieties based on physiological and agronomical characteristics at Yazd region

Document Type : Research Paper

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Abstract

In order to study of drought stress on physiological and agronomical
characteristics of rapeseed varieties, an experiment was carried out as split plot based
on randomized complete block design with three replications at Yazd region during
of 2011-2012. Irrigation treatments was designed in two levels as main plot including
irrigation after 80 mm evaporation from evaporation pan, class A (control treatment)
and drought stress as withholding irrigation from flowering stage, and varieties lilian,
Cooper and Savannah as sub plots. Sampling stages was done 7, 12 and 26 days after
treatment. The results indicated that drought stress significantly decreased the
stomatal conductivity, relative water content (RWC), plant height, silique per plant,
1000 grain weight and grain yield, whereas, in comparison with control SPAD value
was higher. Lilian indicated the higher stomatal conductivity (196 mmol m-2 s-1) and
RWC, silique per plant (300 silique), 1000 grain weight (4.06 g) and grain yield
(1411 kg.ha-1). In this study, Geometric mean productivity (GMP) and Stress
tolerance index (STI) had the high correlation with grain yield in normal and drought
stress conditions. Also, Bi-plot diagram based on two principal components
indicated that Lilian variety with higher GMP and STI indices in addition with higher
GMP and STI both in stress and non stress environment had the highest grain yield.

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