Status of wheat development (var. ProINTA Pincen) at last foliation and grain yield

The Pro INTA Pincen wheat variety is one of the best adapted for dual purpo se; a glasshouse experiment was carried out to determine how the degree of plant development when last defoliated affects grain production. The treatm ents were: no defoliation (T); defoliation with the apex at the double ridg e stage (DDA); defoliation at the beginning of stem elongation (DIE). Defol iations were done 7 cm above the soil surface, taking care to leave the ape x untouched. Defoliation at DDA produced the same amount of grains/spike as T, whereas defoliation at DIE produced a highly significant 50% grain redu ction (P <0,01). This constraint was attributed to the number of grains/spi ke, which sustained the same proportional decrease. Defoliating ProINTA Pin cen wheat variety at the beginning of stem elongation, would remove more le af area and produce a physiological stress that would reduce leaf area at a nthesis and grain yield.