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Plant Traits Associated with Grazing‐Tolerant Alfalfa
Author(s) -
Brummer E. C.,
Bouton J. H.
Publication year - 1991
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1991.00021962008300060014x
Subject(s) - cultivar , grazing , biology , agronomy , crown (dentistry) , hay , medicago sativa , medicine , dentistry
Most alfalfa ( Medicago sativa L.) cultivars cannot withstand longterm, continuous grazing. This study was conducted to determine if plant morphological traits differ among alfalfa cultivars and populations that vary in persistence under grazing stress. Hay‐type cultivars (Apollo and Florida 77), grazing‐type cultivars (Spredor II, Travois, and Alfagraze), and populations derived from these cultivars that survived continuous grazing for l or 2 yr were space‐planted in the field in 1987 and 1988. Plants were clipped biweekly for 16 wk. Decumbency, stem number and diameter, crown area, and herbage yield were measured at five 4‐wk intervals (Dates 1‐5). Crown buds were counted in the fall. Original populations from Spredor II and Travois had thinner stems, more decumbent growth, lower herbage yield, and more stems (at Date 1) when compared with populations from Florida 77 and Apollo. Alfagraze had many, thick stems, intermediate decumbency, and high herbage yield, indicating these traits can be realized along with grazing tolerance. Alfagraze and Travois had the most crown buds. Selected plants of some cultivars had fewer stems and more decumbent growth initially, but differed little from their original populations for these traits after 120 d of frequent clipping. Year‐2 selections from Sprdor II and Florida 77 had more crown buds than their original populations. Genetic coefficients of variation suggested that selection had resutled in little reduction in genetic variation and that further selection for all traits may be possible in each cultivar.