Comparative responses of Plicatula group of Paspalum to cold stress under controlled and field conditions

MARÍA LAURA VIDOZ; PATRICIO COWPER COLES; CARLOS A. ACUÑA; FRANCESCO MIGNOLLI

Congreso; 33° Reunión Argentina de Fisiología Vegetal; 2021

Cold stress is one of the major factors limiting crop productivity. Its intensity depends on how low temperatures are (chilling vs freezing). Freezing events in northeastern Argentina affect pasture quality and limit the use of forage species in livestock productions. Different Paspalum species have shown diversity in their response to cold stress. The aim of the present study was to validate an experimental assay for the identification of contrasting accessions of Paspalum (Plicatula group) regarding cold tolerance. A group of 28 different accessions was initially subjected to 15 °C for 15 h, followed by 5 °C for 4 h and finally to -3 °C for 3 h. A visual damage rating of the canopy was conducted 24 h after removal from the chamber, with leaf damage ranging from 100 % to 8 %. These data were compared with the Normalized Difference Vegetation Index (NDVI) measurements of plants under field conditions, which ranged between 69 % and 11 % of reduction in NDVI. The two most and the two least tolerant accessions were selected to study the chilling response, in order to see the effects of low temperatures on physiological traits. ML1 and U100 accessions, corresponding to P. plicatulum and P. guenoarum, were the cold tolerant selected materials, characterized by the survival and maintenance of greener leaves. While U44 and Q4334 accessions, corresponding to P. atratum and P. guenoarum, were the nontolerant selected materials, which leaves showed wilting, browning and desiccation.