Seed size effects on emergence, height growth, and shoot biomass of first-year alfalfa grown in saline media.

摘要

Rangelander lucerne grown from large, medium, and small size seed while subjected to saline rooting media was evaluated for plant emergence, height growth, and shoot biomass production. The experiment utilized Canada's Salinity Tolerance Testing Facility, featuring a controlled environment simulating field conditions. Test plants were grown in sand tanks flushed four times daily with hydroponic solutions consisting of nutrients and salts dominated by sulfate anions targeting electrical conductivity (EC_sol) treatments of 1.4 (nutrients only), 4, 8, 12, 18, and 24 dS m-1. Seed averaging 1.30, 1.70, and 2.16 g per 1000 kernels, representing small, medium, and large sizes, respectively, averaged 58.5, 65.4, and 74.8% in cumulative emergence and early survival of the best attainable from saline substrates within the 8, 12, 18, and 24 dS m-1 treatments. The vegetative growth of crop plants derived from large seed appeared to be less affected by the salinity than those emerging from smaller seed, but this advantage failed to fully compensate for the negative impact of the salinity. Shoot biomass yields from the first harvest cut of the forage grown from large lucerne seed exceeded yields from small seed by 9, 31, 30, 107, 154 and 717% in the respective root zone ECsol treatment solutions; the medium seed compared to the small size showed a similar trend with respective extra forage yields of 7, 30, 5, 29, 56 and 100%. Large seed improved seedling emergence and survival in slightly and moderately saline media by 7%, crop height after emergence by 0.5% per day, and first-year forage production by 7% in comparison to the values obtained from the lucerne grown from seed sown without size separation.