THERMAL REQUIREMENTS FOR GERMINATION OF SORGHUM SEEDS

LÁZZARI, CÉSAR; LEDESMA, CLAUDIA; LEDESMA, MARÍA MICAELA; FERNÁNDEZ, ELENA

La Falda

Congreso; XXI Annual Scientific Meeting; 2017

Knowledge of the thermal requirements for germination allows sorghum (Sorghum bicolor) genotypes to be sown at different moments, considering the environmental conditions at the time of sowing, and the conditions during the crop cycle. The objective of this study was to evaluate the germination response of five sorghum genotypes at constant temperatures during the process. The germinative power and vigor of the seeds of each genotype were analyzed.The germination test was conducted in growth chambers with constant temperaturesevery 2 °C in a range between 8 and 40 °C, and evaluated daily. The seed that developed a seedling with a 3 cm radicle and 2 cm coleoptilewas considered germinated. There were genotypic differences in the response to the parameters evaluated. The percentage of germination was not significantly modified over a wide temperature range, although there were differences between the genotypes. The mean time of germination was inversely affected by temperature; there was a turning point at 16°C, increasing significantly below this value. The germination rate decreased with low temperatures (10-14 °C), causing staggered germination. The base temperature varied between 9.4 and 11.1 °C, the optimum temperature, between 30.7 and 36.1 °C and the maximum temperature, between 38.2 and 41.1 °C, according to the genotype. Thermal germination time varied between 28.7 and 48.0 °Cd, according to the genotype.