Document Type

Article

Publication Version

Version of Record

Publication Date

2018

Keywords

Lucerne, yellow-flowered alfalfa, saline soil, salinity, growth stage, emergence, seed germination, electrical conductivity

Abstract

Soil salinity limits plant growth and crop production. More than 20% of cultivated land worldwide is affected by salinity. The situation is becoming more severe due to shifts in precipitation and evaporation patterns and improper irrigation. There is an urgent need to develop salt-tolerant, economically valuable plants to minimize the loss of and to sustain agricultural production. Alfalfa is one of the most extensively cultivated forage crops. Some yellow-flowered alfalfa (Medicago sativa subsp. falcata) have exhibited morphological and physiological drought tolerance. Since soil salinity is associated with physiological drought, it is reasonable to expect that these drought tolerant falcata populations could be used for selecting potential parent materials for breeding salt-tolerant cultivars. Uniform seeds from eight alfalfa populations were selected, scarified, and inoculated with rhizobium before being seeded in pre-mixed salt-affected soil. Populations consisted of three falcata plant introductions (PIs), four predominately falcata, and one conventional-hay type as a control. Thirty-six seeds of each population were seeded in six rows per tray with four replicates. Emergence rate, survival, and growth stage were measured after 60 days. The results showed that relative emergence decreased as soil salinity levels increased. Relative emergence increased sharply then plateaued in low saline soil. In medium and high saline soils, relative emergence increased gradually and then also plateaued. PI631678 and PI502441 appeared to show characteristics in line with those of droughttolerant alfalfa under drought stress, having the most promise as potential parent materials. Most populations consisted primarily of growth stage classes one and two except for ‘Persist II’ and ‘Wind River’, which had a significant amount of advanced development at growth stage class three. Persist II and Wind River populations also had the highest relative emergence despite not being regarded as drought-tolerant populations. These unexpected results could be due to seed size rather than other genetic characteristics.

Publication Title

Proceedings of the South Dakota Academy of Science

Volume

97

First Page

93

Last Page

104

Publisher

South Dakota State University

Rights

In copyright

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