Agricultural composition of indoleacetic acid having increased photostability, process for the production and use thereof

A process for the production of an agricultural composition comprising the steps of:

• (a) fermenting a culture comprising one or more indoleacetic add (IAA)-producing bacterial strains in the presence of tryptophan in a culture medium for about 18 to about 96 hours, wherein the one or more IAA-producing bacterial strains comprise strains of Azospirillum brasilense;
• and
• (b) stabilizing the fermented culture under temperature and pressure conditions that promote the conversion of nitrogen sources and reducing sugars into melanoidin-type pigments via the Maillard reaction, wherein the stabilization is carried out for about 15 to about 120 minutes to obtain the agricultural composition that exhibits increased photostability relative to an IAA containing agricultural composition with no melanoidins.