Leaf characteristic variation in hybrid lovegrass populations.
1994
Voigt P.W. | Tichler C.R.
Apomictic plant breeding is being practiced in several turf and forage grasses. Variation released during apomictic breeding has been discussed, but few reports have quantified this variation. Our objectives were to characterize variation among lovegrass, Eragrostis curvula (Schrad.) Nees, hybrids and their parents, compare parents and hybrids, and determine interrelationships among the characteristics studied. Twenty-nine hybrids from each of two populations, A and B, resulting from the cross of two sexual plants (full-sibs with low levels of epicuticular wax (wax) and narrow leaves) with an apomictic plant (high levels of wax and wide leaves) were studied in separate experiments conducted in 1989 and 1990. Leaf width and wax, moisture content (weight) per leaf area, and specific leaf weight (dry weight per leaf area) were studied. Parents differed and variation among hybrids was significant (P < 0.01) for all four characteristics in both studies. The range of the hybrids exceeded that of the parents in all cases. Transgressive segregation was observed only for greater wax, leaf width, and weight and could have resulted in part from extra chromosomes transmitted from the male parent, a plant with 2n= 7x = 70 chromosomes, compared to the 20 chromosomes expected from the tetraploid female parents. Hybrids that were recombinants, e.g., high wax and narrow leaves or low wax and wide leaves, were frequently observed. Both extreme individuals (transgressive segregants) and hybrids with less extreme but new combinations of characteristics (recombinant individuals) were available for selection even within these relatively small populations. Release of genetic variation during apomictic plant breeding can be extensive.
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