GENETIC-PARAMETERS FOR OIL YIELD IN A POPULATION OF CUPHEA-LANCEOLATA

Cuphea lanceolata Ait. f. is a new oilseed crop being developed as a source of capric acid. Little is known about genetic variation for economically important traits in this or other Cuphea species. Our objectives were to estimate genetic parameters for oil yield, seed yield, seed oil content, and seed weight using half-sib families in two diverse environments and to devise a selection scheme for oil-yield improvement in C. lanceolata. In 1987, we derived 160 half-sib families from a broad-based synthetic population (LN-43). These families were grown in a replications-in-incomplete-blocks experiment design at Corvallis and Medford, OR in 1988. There were significant (P less-than-or-equal-to 0.05) additive genetic variances for all traits based on individual-location analyses and for all traits except seed yield based on combined-location analyses. Family X location variances were significant (P less-than-or-equal-to 0.05) for oil and seed yields. Family-mean heritabilities for oil yield, seed yield, oil content, and seed weight were 0.24, 0.20, 0.46, and 0.58, respectively. Additive genetic correlations of oil yield with seed yield, oil content, and seed weight were 0.93, 0.91, and 0.85, respectively. The significant additive genetic variances, moderate heritabilities, and positive expected selection responses observed in LN-43 for oil yield suggests this population has adequate genetic variation for increasing the mean oil yield per unit area of C. lanceolata. Selections for oil-yield improvement should be by direct selection based on results at Medford where the environment was more appropriate for the commercial production of C. lanceolata.