Seed and pollen parents affect the weight of F1 seeds and the number of days until emergence in tea

Abstract

In tea breeding, the relationship between seed weight and growth after germination has implications for the selection of hybrid seedlings. We found that the seed weight was positively correlated with the fresh shoot weight of 6-month-old seedlings. No relationship was observed between the seed weight and the number of seeds per fruit in some of the populations derived from natural crosses. Both seed and pollen parents influenced the weight of F1 seeds. The influence of the pollen parent on the seed weight resembled xenia, a genetic effect of endosperm (3n). However, since tea seed is exalbuminous, and the cotyledons of the embryo occupy most of the volume and weight of the mature seed, the phenomenon of "pseudo-xenia" that we observed might correspond to the effects of the F1 embryo (2n). Both seed and pollen parents also influenced the number of days until the emergence of F1 seed. However, the seed weight did not play a major role in the time of emergence. Our results indicate that tea seed weight and the number of days until emergence are controlled independently by genetic factors of both seed and pollen parents.