ACCUMULATION OF DRY MATTER, IMBIBITION, VIABILITY AND GERMINATION OF IMMATURE SORGHUM SEEDS

Abstract

The achievement of the germination of physiological inmature seeds of sorghum [Sorghum bicolor (L.) Moench] could allow breeders to accelerate generations of inbreeding, mainly in those areas where temperature and water are not limiting factors, as it happens in the southem areas of México where this crop is getting more important. In order to know in which developmental stage of the grain filling period could inmature seeds be harvested, an study on viability, germination, dry matter accumulation and imbibition of seeds was carried out under laboratory conditions in four sorghum lines (PP 290, Tx 378, Tx 430 y Tx 625), which were harvested each seven day after anthesis. Seed viability and germination of PP 290 and Tx 625 harvested seven days after flowering were 75 and 71%, and 23 and 17%, respectively. Seeds of the four genotypes harvested 14 days after anthesis showed between 56 and 99% of viability and germination respectively; those harvested 21 days after anthesis showed germination values higher than 92%, while viability reached values statistically equal to 100%. Dry matter accumulation of seeds followed two types of behaviour depending upon de length of the grain filling period. In both patterns, however, the highest dry matter accumulation was reached one or two days before physiological maturity (black layer presence) was obtained. lmbibition correlated negatively with dry matter accumulation and with seed age; most of the water absorption occurred during the first 12 hours.