SEEDLING-SELECTION EFFECTS ON MORPHOLOGICAL TRAITS OF MATURE PLANTS IN RED-CLOVER

Knowledge of the correlation between juvenile- and mature-plant traits is critical in determining the opportunities for early stage selectio n. The effects of early stage selection on mature-plant performance ha ve rarely been quantified. This study was conducted to identify seedli ng traints in red clover (Trifolium pratense L.) that correlate to mat ure-plant traits and to evaluate the effect of seedling selection on f orage yields and other mature-plant traits. The results showed that re lationships between most seedling- and mature-plant traits were weak ( r ranged from -0.170 to 0.239). Nevertheless, selecting the top 10% se edlings for petiole length, days from emergence to full expansion of t he 4th leaf (D4LE), or leaves per seedling, produced a mature-plant po pulation with higher individual plant dry weight (IPDW1) and higher an nual yield in 1993 (Y93). Selection for leaves per seedling increased IPDW1 by 23.2%. Selection for petiole length and the smallest D4LE inc reased Y93 by 15.7% and 13.8%, respectively. Furthermore, substantial expected genetic gains were obtained for IPDW1 and Y93 when selecting for some seedling traits. We conclude that plants and families with lo w potential yield can be eliminated at the seedling stage in red clove r. This will allow breeders to increase the number of superior plants to be field tested or to conduct a more rigorous evaluation of the sel ected plants. Among the five selection schemes tested for direct selec tion of mature-plant traits, mass selection produced the largest genet ic gain.