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DROUGHT TOLERANCE
STUDIES THROUGH WSSI AND STOMATA IN UPLAND
COTTON
MUHAMMAD JURIAL BALOCH1*,
NAQIB ULLAH KHAN2, WAJID ALI JATOI1, GUL HASSAN2, ABDUL AZIZ KHAKHWANI3,
ZAHOOR AHMAD SOOMRO1 AND NASREEN FATIMA VEESAR1
Abstract:
Water stress
susceptibility index (WSSI) and stomatal conductance were used to
determine the stress tolerance of 10 upland cotton cultivars during 2009
at Sindh Agriculture University, Tandojam, Pakistan. The experiment was
conducted in spilt plot design with irrigations as main plots and
cultivars as sub-plots. Two irrigation treatments were used i.e. one has
two irrigations (water stress) and other has eight irrigations
(non-stress). Analysis of variance revealed significant genotypic
differences about WSSI for all the traits. Non-significant interaction
between irrigations and cultivars for seed cotton yield and boll weight
exhibited varietals stability over irrigation regimes, whereas
significant interactions between above parameters for plant height and
bolls per plant suggested genotypic instability over irrigation
treatments for these traits. Overall, cultivars mean performance for all
the traits in stress conditions was poor as compared to non-stress
conditions, nevertheless some cultivars exhibited nonsignificant mean
differences in both irrigation regimes, thus showing higher stress
tolerance. The WSSI values of seed cotton yield as displayed in biplot
revealed that cultivars CRIS-477, CRIS-483 and CRIS-486 were found
highly susceptible to water stress. Cultivars CRIS-476, CRIS-482,
CRIS-487 and NIAB-78 were characterized as highly susceptible with
minimum production even under optimum irrigation conditions. Cultivar
CRIS-9 was moderately tolerant as produced low production. However,
cultivars CRIS-485 and CRIS-484 were found highly stress tolerant
because of minimum WSSI value and lower stomatal conductance. Negative
correlations between water stress and WSSI for seed cotton yield and
plant height revealed that any increase in the degree of stress caused a
corresponding decrease in WSSI.
1Sindh Agriculture University, Tandojam, Pakistan.
2Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan.
3Department of Agronomy, Faculty of Agriculture, Gomal University, Dera
Ismail Khan, Pakistan
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