SPRAYED ABA ENHANCES PHYSIOLOGICAL PARAMETERS AND YIELD COMPONENTS IN FIELD-CULTURED SOYBEAN

TRAVAGLIA C; REINOSO H; BOTTINI R

Puerto Vallarta, México

Congreso; IPGSA Conference; 2007

IPGSA

This work evaluated the effect of exogenous ABA on to the physiology and yield performance of field-cultured soybean during three years. The hypotheses were that ABA alleviates temporary water stress hence promoting growth, and it upholds carbohydrate re-mobilization towards seeds. ABA 300 mg L-1 was sprayed at the 7 leaves stage and repeated in anthesis. The results indicate that ABA increased stomatal conductance and transpiration rate in the mid term, with a lower leaf temperature. ABA also augmented the content of leaf pigments. By consequence aerial mass increased because of broad shoots and higher leaf area (although only significant in the upper part of canopy), and shoot soluble carbohydrates were enhanced. The main root of ABA-treated plants was shorter, but with more lateral roots and, importantly, the number and weight of effective nodules were not affected by the hormone. The number of pods per plant was also improved, and the average weight of grains was significantly enhanced. The seeds had higher oil content, without variation in proteins. The results suggest that ABA favored the photosynthetic activity by both, increases in leaf area and pigments. It also confirms results with other species (wheat) in incrementing assimilate export towards storage organs. Such effects were reflected in yield increases, without affecting the seed quality.