Constitutive water-conserving mechanisms are correlated with the terminal drought tolerance of pearl millet [Pennisetum glaucum (L.) R. Br.]

Kholova, J and Hash, C T and Aparna, K and Kočová, M and Vadez, V (2010) Constitutive water-conserving mechanisms are correlated with the terminal drought tolerance of pearl millet [Pennisetum glaucum (L.) R. Br.]. Journal of Experimental Botany, 61 (2). pp. 369-377.

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Abstract

Pearl millet, a key staple crop of the semi-arid tropics, is mostly grown in water-limited conditions, and improving its performance depends on how genotypes manage limited water resources. This study investigates whether the control of water loss under non-limiting water conditions is involved in the terminal drought tolerance of pearl millet. Two pairs of tolerant3sensitive pearl millet genotypes, PRLT 2/89-33–H77/833-2 and 863B-P2–ICMB 841-P3, and near-isogenic lines (NILs), introgressed with a terminal drought tolerance quantitative trait locus (QTL) from the donor parent PRLT 2/89-33 into H77/833-2 (NILs-QTL), were tested. Upon exposure to water deficit, transpiration began to decline at lower fractions of transpirable soil water (FTSW) in tolerant than in sensitive genotypes, and NILs-QTL followed the pattern of the tolerant parents. The transpiration rate (Tr, in g water loss cm22 d21) under well-watered conditions was lower in tolerant than in sensitive parental genotypes, and the Tr of NILs-QTL followed the pattern of the tolerant parents. In addition, Tr measured in detached leaves (g water loss cm22 h21) from fieldgrown plants of the parental lines showed lower Tr values in tolerant parents. Defoliation led to an increase in Tr that was higher in sensitive than in tolerant genotypes. The differences in Tr between genotypes was not related to the stomatal density. These results demonstrate that constitutive traits controlling leaf water loss under well-watered conditions correlate with the terminal drought tolerance of pearl millet. Such traits may lead to more water being available for grain filling under terminal drought.

Item Type: Article
Divisions: UNSPECIFIED
CRP: UNSPECIFIED
Subjects: Mandate crops > Millets
Depositing User: Library ICRISAT
Date Deposited: 17 Aug 2011 07:03
Last Modified: 04 Sep 2017 08:41
URI: http://oar.icrisat.org/id/eprint/240
Official URL: http://dx.doi.org/10.1093/jxb/erp314
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: The authors thank Mr M Anjaiah for expert technical support for the experiments and Ms Rekha Badham for support with the statistical analysis. Support for the senior author came from a grant from DFID-BBSRC, Research Contract BB/F004133/1 and from Grant No. MSM0021620858 from the Ministry of Education, Youth and Sports of the Czech Republic.
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