Sink limitations to yield in wheat : how could it be reduced?
MetadataShow full item record
Further genetic gains in wheat yield are required to match expected increases in demand. This may require the identification of physiological attributes able to produce such improvement, as well as the genetic bases controlling those traits in order to facilitate their manipulation. In the present paper, a theoretical framework of source and sink limitation to wheat yield is presented and the fine-tuning of crop development as an alternative for increasing yield potential is discussed. Following a top-down approach, most crop physiologists have agreed that the main attribute explaining past genetic gains in yield was harvest index (HI). By virtue of previous success, no further gains may be expected in HI and an alternative must be found. Using a bottom-up approach, the present paper firstly provides evidence on the generalized sink-limited condition of grain growth, determining that for further increases in yield potential, sink strength during grain filling has to be increased. The focus should be on further increasing grain number per m2, through fine-tuning pre-anthesis developmental patterns. The phase of rapid spike growth period (RSGP) is critical for grain number determination and increasing spike growth during pre-anthesis would result in an increased number of grains. This might be achieved by lengthening the duration of the phase (though without altering flowering time), as there is genotypic variation in the proportion of pre-anthesis time elapsed either before or after the onset of the stem elongation phase. Photoperiod sensitivity during RSGP could be then used as a genetic tool to further increase grain number, since slower development results in smoother floret development and more floret primordia achieve the fertile floret stage, able to produce a grain. Far less progress has been achieved on the genetic control of this attribute. None of the well-known major Ppd alleles seems to be consistently responsible for RSGP sensitivity. Alternatives for identifying the genetic factors responsible for this sensitivity (e.g. quantitative trait locus (QTL) identification in mapping populations) are being considered.
NotePonència presentada al International Workshop on Increasing Wheat Yield Potential, CIMMYT, Obregón, Mèxic, del 20 al 24 de març de 2006.
Is part ofJournal of Agricultural Science, 2007, vol. 145, núm. 2, p. 139-149
European research projects
Showing items related by title, author, creator and subject.
Slafer, Gustavo A.; Elia, Mónica; Savin, Roxana; García, Guillermo A.; Terrile, Ignacio I.; Ferrante, Ariel; Miralles, Daniel J.; González, Fernanda G. (John Wiley & Sons Ltd.Association of Applied Biologists, 2015)Further improvements in wheat yields are critical, for which increases in grain number would be required. In the recent past, higher grain number was achieved through increased growth of the juvenile spikes before anthesis, ...
Influence of "historic" photoperiod during stem elongation on the number of fertile florets in wheat Miralles, D. J.; Slafer, Gustavo A.; Richards, R. A. (Cambridge University Press, 2003)Extending the duration of the late reproductive phase in wheat has been proposed as a possible avenue to improve spike fertility. There is a positive correlation between the number of fertile florets and the duration of ...
Quantitative developmental response to the length of exposure to long photoperiod in wheat and barley Miralles, D. J.; Slafer, Gustavo A.; Richards, R. A.; Rawson, H. M. (Cambridge University Press, 2003)The present study was designed to analyse the effect of the length of exposure to a long photoperiod imposed c. 3 weeks after sowing in spring wheat (cv. UQ189) and barley (cv. Arapiles) to (i) establish whether the ...