Effect of the temperature and photoperiod during the germination and emergency of alfalfa (Medicago sativa L.) with different degrees of winter rest

Abstract

Alfalfa is the most widespread worldwide and national forage species.
The market offers a lot of varieties according to different characteristics. The aim of
this study was to evaluate the effect of temperature and photoperiod (simulating
autumn and spring conditions) on seed germination and seedling emergence
of different fall dormancy groups (FDG) of alfalfa. The assay was performed in
germination chamber and percentage of appearance of cotyledonary leaves,
unifoliate leaf and trifoliate leaf, and weight of seedlings was compared at
different days after sowing (DAS). The average temperatures used were; 10, 20
and 30 ºC, while the FDG were: intermediate (6) and extremely short (10). As
for temperatures, there were significant differences for 20ºC in favor of a higher
percentage of cotyledonary leaf appearance 5 DAS, of unifoliate leaf at different
DAS, and of trifoliate leaf at 55 DAS. The weight of seedlings was statistically lower
for 30ºC in all the stages analyzed, while the greater weight was measured at
20ºC for all phases, at 10ºC, no differences were observed, except in unifoliate
leaf stage. Regarding the FDG, significant differences were observed for higher
percentage of cotyledonary leaves and trifoliate leaf in FDG 6. In conclusion, when
the temperatures are lower than the optimum in sowing, intermediate to long
FDG should be used.