To accelerate the breeding of salt-alkali-tolerant alfalfa （Medicago sativa L.） varieties， in this study 19 alfalfa germplasms were used to establish a seedling-stage screening system for identifying salt-alkali-tolerant materials. By combining generation breeding， salt-alkali-tolerant alfalfa germplasms were rapidly propagated to obtain the first generation hybrid （F1）， which were subsequently evaluated for salt-alkali tolerance. The results showed that two-week-old alfalfa seedlings treated with 0.1 mol·L^-1 Na⁺ （NaCl∶NaHCO₃=1∶1， pH=8.5） for 72 h could be effectively used to screen salt-alkali-tolerant individuals. Evaluation of 19 alfalfa germplasms at the seedling stage revealed that cultivars ‘WL-168HQ’ ‘Galaxie Max’ and ‘Bara416’ exhibited significantly higher salt-alkali tolerance than the others. By adjusting the light quality ratio， the FCL5 light condition （450-465 nm （white light） 66.67%， 450-480 nm （blue light） 6.67%， 615-650 nm （red light） 26.66%） was identified as optimal， which supported healthy growth and high induction efficiency. Under FCL5 condition， 110 elite salt-alkali-tolerant plants were subjected to flowering induction and open pollination to produce F1 half-sib family seeds. Evaluation of six F1 half-sib families demonstrated that the proportions of salt-alkali-tolerant plants in ‘Octane’‘Bara416’ and ‘ZN-CT25’ families were significantly higher than those of unselected commercial cultivars. This study provides technical support and valuable germplasm resources for the breeding of new salt-alkali-tolerant alfalfa varieties.

Alfalfa  /  salt and alkali resistance  /  generation breeding  /  screening evaluation