Yield, transpiration efficiency, and water-use variations and their interrelationships in the sorghum reference collection

Vadez, V and Krishnamurthy, L and Hash, C T and Upadhyaya, H D and Borrell, A K (2011) Yield, transpiration efficiency, and water-use variations and their interrelationships in the sorghum reference collection. Crop and Pasture Science, 62 (8). pp. 645-655. ISSN 1836-5795

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Sorghum is well adapted to water-limited conditions, but the traits responsible for this enhanced adaptation under drought conditions remain unclear. In this study, yield, transpiration efficiency (TE) and water extraction were assessed in 149 germplasm entries from the sorghum reference set (plus three control cultivars) using a lysimetric system under terminal water stress and fully irrigated conditions outdoors. A 10-fold range for grain yield and harvest index (HI), 2-fold range for TE and a 1.25-fold variation for water extraction were observed under terminal water stress conditions. Transpiration efficiency and water extraction under water stress related poorly to that under fully irrigated conditions, reflecting a large genotype-by-water treatment interaction. Under drought stress, total water extraction varied by ~3 L plant–1 among germplasm. Entries from the Durra race had highest water extraction capacity, whereas Caudatum-Bicolor and Caudatum-Durra intermediate races had poor water extraction. Durra, Caudatum and Caudatum-Guinea races had highest TE, whereas the Guinea race had the lowest. Although yield was closely related to HI, at any level of HI there were substantial yield differences that remained unexplained, and these residual yield variations were closely related to TE (R2 = 0.60). Similarly, substantial yield variations that were still not explained by HI or TE were closely related to the total water extracted under water stress (R2 = 0.35). A multilinear regression analysis confirmed these results and showed the importance of water extraction during grain filling. Therefore, next to HI, the yield differences under terminal drought in sorghum were driven by TE, and then next by water extraction. The large genetic variation for TE and water extraction offer great breeding opportunities and in particular, highlight the Durra race as a critical source of variation.

Item Type: Article
Uncontrolled Keywords: germplasm reference set, pre-anthesis water use, roots, water uptake profile
Subjects: Mandate crops > Sorghum
Depositing User: Users 6 not found.
Date Deposited: 15 Sep 2011 04:53
Last Modified: 30 Nov 2011 06:11
URI: http://oar.icrisat.org/id/eprint/1537
Official URL: http://dx.doi.org/10.1071/CP11007
Funders: Australian Centre for International Agriculture Research, Generation Challenge Programme
Acknowledgement: Work was funded by a grant from the Australian Centre for International Agriculture Research (ACIAR) (CIM-2007-120) and by a grant by the Generation Challenge Program (G4008.02 – SP1). Authors are thankful to Dr Neil C. Turner for critically reading the manuscript. Authors are grateful for the expert technical help from Mr N. Pentaiah and Mr M. Anjaiah.
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