Has long-term selection for yield in durum wheat also induced changes in leaf and canopy traits?

Giunta, F. and Motzo, R. and Pruneddu, G. (2008) Has long-term selection for yield in durum wheat also induced changes in leaf and canopy traits? Field Crops Research, 106 (1). pp. 68-76.

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Over the last century, most of the genetic gain in the grain yield of Italian durum has been achieved by an increase in the harvest index and promotion of flowering time. We report the indirect effects of this long-term selection on a number of leaf and canopy traits associated with photosynthesis. In a 2-year experiment, using different sowing dates and nitrogen regimes, these characters were assessed for a set of 20 cultivars released between 1900 and 2000. Leaf area, specific leaf area, specific leaf nitrogen content and stomatal resistance were all negatively correlated with year of release, whereas canopy temperature showed a positive correlation. The substantial reduction in plant height, by which the rise in harvest index was achieved, was partly responsible for the rise in canopy temperature, acting via its effect on aerodynamic resistance. Senescence, when expressed in thermal time after anthesis, was delayed for the modern cultivars, and this delay could be associated with a greater quantity of nitrogen allocated to the grain. The association of senescence onset with earliness suggests a likely role of increased earliness in delayed senescence. The yield increase over time was correlated with a decrease in stomatal resistance and in specific leaf nitrogen content.

Item Type: Article
Uncontrolled Keywords: Breeding; Canopy temperature; Durum wheat; Specific leaf nitrogen content; Stomatal resistance; Senescence
Author Affiliation: Dipartimento di Scienze agronomiche e Genetica vegetale agraria, Facoltà di Agraria, Università di Sassari, Via De Nicola, 07100 Sassari, Italy
Subjects: Crop Improvement > Plant Breeding
Divisions: Other Crops
Depositing User: Mr Siva Shankar
Date Deposited: 11 Sep 2013 04:52
Last Modified: 11 Sep 2013 04:52
Official URL: http://dx.doi.org/10.1016/j.fcr.2007.10.018
URI: http://eprints.icrisat.ac.in/id/eprint/11677

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