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Carbon Isotope Discrimination as a Tool to Improve Water‐Use Efficiency in Tomato
Author(s) -
Martin Bjorn,
Tauer Charles G.,
Lin Robert K.
Publication year - 1999
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1999.3961775x
Subject(s) - water use efficiency , lycopersicon , biology , dry weight , agronomy , horticulture , botany , mathematics , photosynthesis
Carbon isotope discrimination (Δ) is a property that may be used to improve water‐use efficiency (WUE). This study tested the association between Δ and WUE with plant materials and growth conditions likely to disrupt the link between Δ and WUE. The cultivated tomato, Lycopersicon esculentum Mill. cv. UC82B, a drought‐resistant related species, L. pennellii (Cor.) D'Arcy accession LA716, and the F 1 and F 2 generations of the L. esculentum × L. pennellii cross were grown in containers in wet and dry field environments. The wet environment was repeated in a second year and plants were split into groups terminated early and late in the season. The F 1 generation had greater mean WUE and dry weight (DW) than L. esculentum , but the DW advantage was not maintained in the F 2 generation. Low Δ of L. pennellii suggested that leaf WUE was high, but its whole plant WUE varied relative to the other plant materials in the different environments. There was a negative correlation between Δ and WUE in the F 2 generation, and WUE was generally positively correlated with DW. However, low Δ was associated with large DW in only one environment and with small DW in three environments. Averaged across environments, the top 10% of the plants ranked by WUE had 47% greater WUE than the bottom 10%. In comparison, the bottom 10% ranked by Δ had an average of 16% greater WUE than the top Δ group, but in three of the four environments the bottom group accumulated 33 to 47% less DW than the top Δ group. This study on tomato suggests that WUE can be increased by selecting low Δ, but selecting low Δ alone may identify a subpopulation of small plants. Dry weight could probably be increased by traditional breeding techniques.