Manipulation of senescence, source-sink relationship and yield of wheat by growth regulating chemicals

When sprayed on the whole plant, IAA accelerated senescence (as determined by the loss of chlorophyll and protein) of the leaves and glumes (source) and reduced most of the physical yield parameters at harvest, although protein, free aminonitrogen of the seeds and mobilization index for protein (grain protein: flag leaf plus glume protein ratio) increased by this treatment. Kinetin, ABA, GA₃ and Dithane M-45 deferred senescence (ABA only increased chlorophyll level) of the source organs and increased most of the yield determining components, PMA, α-HPMS and CCC accelerated senescence and lowered the yield parameters at harvest.

Application of kinetin or ABA either on the lag leaf or on the ear deferred senescence of the treated leaf or the glumes and also increased yield attributes excepting when kinetin treated on the flag leaf. Protein levels were inversely related to the percentage of moisture levels of the seeds at harvest.