Wheat yield progress associated with higher stomatal conductance and photosynthetic rate, and cooler canopies

Citation
Ra. Fischer et al., Wheat yield progress associated with higher stomatal conductance and photosynthetic rate, and cooler canopies, CROP SCI, 38(6), 1998, pp. 1467-1475
Citations number
33
Categorie Soggetti
Agriculture/Agronomy
Journal title
CROP SCIENCE
ISSN journal
0011183X → ACNP
Volume
38
Issue
6
Year of publication
1998
Pages
1467 - 1475
Database
ISI
SICI code
0011-183X(199811/12)38:6<1467:WYPAWH>2.0.ZU;2-W
Abstract
Grain yields of eight representative semidwarf spring wheat (Triticum aesti vum L.) cultivars released in northwest Mexico between 1962 and 1988 have i ncreased linearly across years as measured in this region during 6 yr under favorable management and irrigation. To understand the physiological basis of this progress and possibly assist future selection for grain yield, lea f traits were determined during 3 yr in the same study. Stomatal conductanc e (g(s)), maximum photosynthetic rate (A(max)), and canopy temperature depr ession (CTD), averaged over the 3 yr, were closely and positively correlate d with progress in the 6-yr mean yield. The correlation was greatest with g (s) (r = 0.94, P < 0.01). Compared with the overall yield increase of 27%, g(s) increased 63%, A(max) increased 23%, and canopies were 0.6 degrees C c ooler. Carbon-13 isotope discrimination was also positively associated with yield progress (r = 0.71, P < 0.05), but other leaf traits such as flag le af area, specific leaf weight, percentage N and greeness were not, nor was crop growth rate around anthesis. The causal basis of the leaf activity int errelationships is reasonably clear, with both increased intercellular CO2 concentration and increased mesophyll activity contributing to the increase in A(max). However, causal links to the yield progress, and the accompanyi ng increase in kernels per square meter, are not clear. It is concluded tha t g(s) and CTD should be further investigated as potential indirect selecti on criteria for yield.