Shridhar Rao, J and Vadez, V and Bhatnagar-Mathur, P and Narasu, M L and Sharma, K K (2012) Better root:shoot ratio conferred enhanced harvest index in transgenic groundnut overexpressing the rd29A:DREB1A gene under intermittent drought stress in an outdoor lysimetric dry-down trial. Journal of SAT Agricultural Research, 10. pp. 1-7. ISSN 0973-3094
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Abstract
An outdoor confined trial was conducted during the postrainy season of 2009 for physiological evaluation of induced drought tolerance in transgenic plants of groundnut variety JL 24 overexpressing a transcription factor, DREB1A driven by the stress-inducible promoter of the rd29A gene, both from Arabidopsis thaliana. Lysimetric system was used for growing the plants, where intermittent drought stress was imposed at mid-flowering and peak pod-filling stages of the crop, by subjecting plants to a cycle of drying and re-watering. The lysimetric system facilitated complete recovery of roots, thereby, facilitating studies on variations in the root:shoot ratio induced across the genotypes under controlled wellwatered (WW) and imposed drought stress (DS) conditions. Under DS the root:shoot ratio showed a significant (P <0.005) positive correlation with pod yield and harvest index (HI), reflecting clearly the better performance of two transgenic events GNRD11 and GNRD33 than the untransformed variety JL 24. The transgenic event GNRD11, in particular, showed enhanced HI along with significantly higher (P <0.05) seed yield that was 22% and 25% higher than JL 24 and the elite breeding groundnut cultivar ICGV 86031, respectively. Better HI in these transgenic events, when compared to the untransformed control, was mainly due to the effective partitioning of the accumulated biomass, more towards roots and pods while relatively less towards shoot biomass, leading to higher root:shoot ratio and better yield, also suggesting better water use efficiency in the former compared to the latter.
| Item Type: | Article |
|---|---|
| Divisions: | UNSPECIFIED |
| CRP: | UNSPECIFIED |
| Subjects: | Mandate crops > Groundnut |
| Depositing User: | Mr Siva Shankar |
| Date Deposited: | 03 Dec 2012 08:14 |
| Last Modified: | 03 Dec 2012 08:14 |
| URI: | http://oar.icrisat.org/id/eprint/6249 |
| Official URL: | http://ejournal.icrisat.org/index.htm |
| Projects: | UNSPECIFIED |
| Funders: | UGC, India |
| Acknowledgement: | We gratefully acknowledge Dr Kazuko Yamaguchi-Shinozaki of JIRCAS Japan for kindly providing gene construct used in this study. |
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