LEAF CHARACTERISTIC VARIATION IN HYBRID LOVEGRASS POPULATIONS

Apomictic plant breeding is being practiced in several turf and forage grasses. Variation released during apomictic breeding has been discus sed, but few reports have quantified this variation. Our objectives we re to characterize variation among lovegrass, Eragrostis curvula (Schr ad.) Nees, hybrids and their parents, compare parents and hybrids, and determine interrelationships among the characteristics studied. Twent y-nine hybrids from each of two populations, A and B, resulting from t he cross of two sexual plants [full-sibs with low levels of epicuticul ar wax (wax) and narrow leaves] with an apomictic plant (high levels o f wax and wide leaves) were studied in separate experiments conducted in 1989 and 1990. Leaf width and wax, moisture content (weight) per le af area, and specific leaf weight (dry weight per leaf area) were stud ied. 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 segre gation was observed only for greater wax, leaf width, and weight and c ould have resulted in part from extra chromosomes transmitted from the male parent, a plant with 2n = 7x = 70 chromosomes, compared to the 2 0 chromosomes expected from the tetraploid female parents. Hybrids tha t were recombinants, e.g., high wax and narrow leaves or low wax and w ide leaves, were frequently observed. Both extreme individuals (transg ressive segregants) and hybrids with less extreme but new combinations of characteristics (recombinant individuals) were available for selec tion even within these relatively small populations. Release of geneti c variation during apomictic plant breeding can be extensive.