Flowering, capsule and seed characteristics in Cuphea

We modeled the flowering and capsule set dynamics, quantified the level of variation in seed characteristics, elucidated the inter-relationships between seed and capsule physical dimensions, and quantified their impact on single seed weight in the cuphea germplasm line PSR23. Temporal patterns of flowering and capsule set were largely time-dependent and highly auto-correlated, with significant autoregressive parameters of number of flowers (0.76) and number of capsules (0.74). Large numbers of seeds per capsule were associated with large coefficient of variation in single seed weight. Seed number and seed weight per capsule, when log-transformed, exhibited a slope of −0.65 indicating that cuphea plants have only a limited capacity to maintain seed weight by adjusting seed number if resources vary. Capsule tissue/seed weight ratio and number of seeds per capsule have the largest potential impact on single seed weight. Sensitivity analyses indicated that capsule perimeter (>76 mm), capsule major (>23 mm) and minor axes (>7.0 mm), capsule circularity (between 0.350 and 0.375), capsule area (<85 mm²), capsule tissue/seed weight ratio (<0.40), and number of seeds per capsule (∼9.0) would optimize single seed weight. This information would help plant breeders exploit genotypic variability in seed and capsule characteristics and agronomists identify optimum trait combinations to produce high yields of this potential oilseed crop.