3D distribution of seed yield in alfalfa seed canopy
Huyghe C., Julier B., Bolaños-Aguilar E.D., Ecalle C.
Unité de Génétique et d’Amélioration des Plantes Fourragères, INRA, 86600 Lusignan, France.
The exhaustive description of the canopy structure is helpful in analyzing the seed yield components and in understanding the yield elaboration.
Spatial distribution of seed yield was investigated in canopies of cv. Europe. On 1 m2 plots, all the stems were collected. They were gathered in classes according to the number of fertile inflorescences carried on their main stem. The number of stems per class was variable across environments but whatever the canopy structure few stems had more than 11 mainstem inflorescences. The seed weight per inflorescence (SWI) was measured for each node position and stem class. The SWI for a given node increased with the number of fertile inflorescences. Along a stem, in a given class, it tends to decline at the upper position. It was shown that the inflorescences of stems carrying few inflorescences weighed similarly to the upper inflorescences of long stems. Thus, a unique relationship was developed between the SWI and the position of the inflorescence counted from the top. The dominant stems give an adequate image of this relationship.
The number of inflorescences carried by the branches of a given stem class is fully related to the number of mainstem inflorescences. The patterns were similar for different canopies with contrasting seed yield
Thus, there are strong physical and physiological rules regulating the seed yield elaboration within a canopy.