Responses of early and latepotatocultivars to moderatedrought conditions: agronomicparameters and carbon isotope discrimination

Deblonde, P.M.K. and Haverkortb, A.J. and Ledenta, J.F. (1999) Responses of early and latepotatocultivars to moderatedrought conditions: agronomicparameters and carbon isotope discrimination. European Journal of Agronomy, 11 (2). pp. 91-105.

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Our main objective was to test under moderatedrought conditions the hypothesis that earlycultivars behave better than latecultivars under conditions of drought occurring late in the season whereas latecultivars would be less susceptible to a drought occurring early in the season. Agronomicparameters [tuber dry weight, harvest index, dry matter content, tolerance to a decrease in water supply (TDWS) and carbonisotopediscrimination (Δ)] were measured in six potato genotypes (Solanum tuberosum L.) subjected in two field trials (1995 and 1996) to three levels of water supply (treatments: 1, rainfall+irrigation; 2, rainfall only; 3, rainfall reduced to stemflow during early growth). In both years, treatment 3 (lower water supply) reduced significantly tuber dry yield and harvest index in comparison with treatment 1 (higher water supply). Tuber dry matter content was increased significantly only by treatment 3 in 1996. For these parameterscultivars did not differ in their response to the lower water regimes except in the case of tuber dry matter content during one year (1996). TDWS defined as tuber dry weight of treated plots relative to the tuber dry weight of treatment 1 allowed more discrimination among the behaviour of cultivars in case of moderatedrought than yield and Δ. Our TDWS results confirm partly the hypothesis tested: in 1996, TDWS values of mid–latecultivars were higher than those of earlycultivars in the case of earlydrought (treatment 3), indicating that latercultivars support better a drought stress in the early part of the season. Differences among cultivars in the responses of Δ to the different water regimes could not be shown, and there was no difference between the values of Δ observed for early and latecultivars. In our moderatedrought conditions an escape mechanism of earliercultivars could not be confirmed through the consideration of the Δ values observed. The linear regression of Δ on TDWS gave a positive slope significantly different from zero (n=24) but the R2 values were low (R2=0.41).

Item Type: Article
Additional Information: We wish to thank Mr. G.W. Valkenburg of the DLO Research Institute for Agrobiology and Soil Fertility (AB-DLO) at Wageningen for the carbon analysis.
Uncontrolled Keywords: Solanum tuberosum L.; Stable isotope; Water stress; Water use efficiency
Author Affiliation: Laboratoire d'Ecologie des Grandes Cultures, Université Catholique de Louvain,Belgium DLO Research Institute for Agrobiology and Soil Fertility,Netherlands
Subjects: Soil Science and Microbiology
Crop Improvement
Divisions: Other Crops
Depositing User: Mr Arbind Seth
Date Deposited: 07 Oct 2012 13:47
Last Modified: 07 Oct 2012 13:47
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