Growth Rate and Yield in Sericea Lespedeza in Relation to Seed Size and Outcrossing1
- Will A. Cope2
Sericea lespedeza seed were obtained from open-pollinated chasmogamous flowers and from self-fertilized cleistogamous flowers from both an outcrossed and a caged plant in each of 10 inbred lines. Chasmogamous seed are approximately 20% heavier than cleistogamous seed; thus, the four progenies in each line allowed comparison of both outcrossing and seed size effects. In a greenhouse test seed size superiority averaged nearly 8% for measurements over a 4-month period; in the field test initial values were similar but disappeared after 2 months. A superiority for outcrossing was apparent in each test only after several weeks, reaching a maximum of 8.5% over the maternal parents at the end of the first growing season in the field. The small increase from outcrossing possibly reflects both a low level of heterosis and a low percent cross-pollination. Within the 10 lines seed size was significantly correlated with seedling performance; thus selection for seed size involves genetic factors for growth rate other than seed size alone. Both seed size and heterosis require attention of the plant breeder; however, the levels of effects reported here place definite restrictions on progress to be expected and breeding systems to be used effectively.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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