versión impresa ISSN 0365-2807
ZAPATA T., Cristian; SILVA C., Paola y ACEVEDO H., Edmundo. Grain yield and assimilate partitioning in wheat isogenic plant height lines. Agric. Téc. [online]. 2004, vol.64, n.2, pp. 139-155. ISSN 0365-2807. http://dx.doi.org/10.4067/S0365-28072004000200003.
The use of wheat varieties with dwarfing genes has permitted the achievement of great increases in production. Nevertheless, it is still unclear how these genes affect the yield and the physiology of the wheat. The objectives of this study were to evaluate the effect of plant height on yield, the stability of yield and the distribution of the assimilates of the distinct components of yield. The bread wheat cultivar Santa Helena and eleven close lines to isogenetic derivatives of this cultivar and carriers of the dwarfing genes Rht1 and/or Rht2 were utilized. The trial was evaluated over three seasons, two in Mexico and one in Chile. The semi-dwarf isolines yielded 21% more than the other groups in all environments, while the tall line only yielded above the average in the poorest environments. As well, the semi-dwarf plants obtained greater biomass (13,746 and 12,974 kg; P < 0.05) and a greater harvest index (0.40; P £ 0.05). This higher yield was due to an increase in the number of grains per spike (22%), which implied and larger number of grains per square meter. However, no differences were observed between isolines in the accumulation of biomass no in the magnitude of the radiation intercepted in the spike growing period. The weight of the grains reduced on reducing the height of the plant. The dwarf lines delayed an average of 4 days more in arriving at shooting and anthesis than the tall isoline and 2 days more than the semi-dwarfs.
Palabras clave : Rht genes; dwarfing genes; potential yield; wheat; Triticum aestivum L..