Selection for Seedling Vigor in Astragalus cicer L.¹

Abstract

The use of cicer milkvetch (Astragalus cicer L.) as a forage legume is restricted because of relatively poor seedling vigor. If sufficient variation exists within the species for seedling vigor, it may be possible to improve this character through a breeding program. Therefore, the objectives of this study were to determine (1) the variability in speed of seed germination and total germination in the laboratory at two alternating temperature treatments, 5–20 C and 15–25 C; (2) the variability in speed of seedling emergence and total emergence in the greenhouse and field; and (3) the relationships among these characters. About 80 polycross progenies, representing 3 basic breeding populations, were evaluated. The populations comprised polycross progenies selected for superior, average, and below‐average vigor. Highly significant differences existed among progenies for speed of seed germination and seedling emergence over all environments. Simple correlation coefficients between the various characters generally were significant, but of a relatively low predictive value. There is a great need for a laboratory technique that will give a reliable measure of seedling vigor under field conditions. Variation among progenies for seedling vigor was large enough to indicate that improvement can be made in cicer milkvetch for this character.

A review of research progress on cicer milkvetch (Astragalus cicer L.)

“…This was confirmed by Townsend and McGuinnies (1972a); they found that forage legumes that were easy to establish in the field were those that germinated rapidly over a wide range of temperatures. Townsend (1974) used two alternating temperature regimes in growth For personal use only. chambers in testing for variation in speed of germination and total germination.…”

“…Of seven progenies that exhibited high rates of germination, emergence and total emergence, two each were from the low-and high-mature plant vigor classes and three from the large-seeded lot, indicating that mature plant vigor is not a reliable indicator of seedling vigor. Selecting at the lower temperature regime was therefore deemed a valuable tool for improving germination characteristics of a population (Townsend 1974) and growth cabinets were better for selection than greenhouses (Townsend and Wilson 1978).…”

Astragalus sect. Dissitiflori (Fabaceae) in Iran

“…The section was revised for the flora of the former Soviet Union (Gonarov et al 1946) and for certain areas, e.g. the flora of Turkey (Chamberlain & Matthews 1970) and the flora of Iraq (Townsend & Guest 1974). Now this section with 149 species is the largest section in bifurcate haired Astragali group (Lock & Simpson 1991, Yakovlev et al 1996, Maassoumi 1998.…”

Selection for Establishment Capacity in Reed Canarygrass

“…Seed size is a heritable trait that has responded to selection and is often positively correlated with seedling vigor (Berdahl and Barker, 1984;DeHaan et al, 2001;Trupp and Carlson, 1971;Twamley, 1974). Seedling vigor and/or germination rate have responded to selection in several species (DeHaan et al, 2001;Lawrence, 1977;Townsend, 1974;Voigt and Brown, 1969). Seedling vigor and/or germination rate have responded to selection in several species (DeHaan et al, 2001;Lawrence, 1977;Townsend, 1974;Voigt and Brown, 1969).…”

“…However, selection for larger seeds may be insufficient as a sole selection criterion to improve seedling vigor (McLean and Nowak, 1997). Seedling vigor and/or germination rate have responded to selection in several species (DeHaan et al, 2001;Lawrence, 1977;Townsend, 1974;Voigt and Brown, 1969).…”