Abstract:

The overall aim of our research is to improve saline-alkali land utilization efficiency and alleviate the competition between grain and forage production in the Ningxia Yellow River irrigation region. To this end， we evaluated and screened 103 triticale （×Triticosecale） germplasm at the germination stage to determine their salt tolerance. Preliminary trials were conducted under a NaCl gradient （0-300 mmol·L^-1）， and the results showed that 200 mmol·L^-1 NaCl was the optimal concentration for evaluation. Three principal components with a cumulative contribution rate of >80% were extracted from the salt tolerance coefficients of survival rate， plant height， shoot fresh weight， root length， and chlorophyll content. Integrated membership function and cluster analyses identified two salt-tolerant genotypes （QT-5， LJ-65） and two salt-sensitive genotypes （M90， M36）. Six representative accessions were further analyzed to determine their germination traits （germination potential， survival rate）， phenotypic parameters （plant height， shoot fresh weight， root length）， and physiological indices ［malondialdehyde （MDA） content， catalase （CAT）， peroxidase （POD） and superoxide dismutase （SOD） activities］. The results show that triticale leaves responded to salt stress earlier than roots. The increase in activities of antioxidant enzymes （CAT， POD， SOD） were greater in salt-tolerant genotypes than in salt-sensitive ones， whereas the MDA content only varied significantly when salt tolerance differed markedly. These findings suggest that the capacity to scavenge reactive oxygen species is crucial for salt tolerance. The results of this study identify elite germplasm resources for salt-tolerant triticale breeding in Ningxia and demonstrate the use of a robust physiological evaluation system to screen salt-tolerant materials.

Key words: triticale, evaluation of salt tolerance, membership function analysis, physiological and biochemical indicators