Assessment of diverse cicer milkvetch (Astragalus cicer L.) germplasm for agro-morphological traits under a stockpiling system

Abstract

Cicer milkvetch ( Astragalus cicer L.) is a non-bloating perennial forage legume suitable for stockpiled grazing in the fall because of its rapid regrowth and high nutritive value. Genetically diverse germplasm are needed for the development of improved cicer milkvetch cultivars that can provide consistent production across variable climatic conditions. The objective of this research was to assess the diversity and relationship of 27 cicer milkvetch populations to inform the selection of populations for future cultivars that have superior agro-morphological traits during summer and fall growth. A completely randomized field trial was established in 2019 near Clavet, Saskatchewan. In 2020 and 2021, forage dry matter yield (DMY), maximum stem length, leaf number per stem, rhizome spread, and stem density were recorded on 27 populations of cicer milkvetch in late June at a first harvest and mid-October at a stockpile harvest. All five traits were different ( p < 0.05) among the populations at both harvests except for leaf number per stem in late June. Principal component analysis identified that the first three principal components described 89% of the variation in agro-morphological traits at the first and stockpile harvests. Of the agro-morphological traits, maximum stem length had the greatest correlation with forage DMY at the first harvest ( r = 0.69) and stockpile harvest ( r = 0.6). Our research demonstrates that there is a high morphological diversity among cicer milkvetch populations, and plant introductions, PI 362266, PI 576963, PI 440143, and PI 362254 could be used as novel genetic resources for the development of climate-resilient cultivars.