Ovule positions within linear fruit are correlated with nonrandom mating in Robinia pseudoacacia.
Post-pollination processes can lead to nonrandom mating among compatible pollen donors. Moreover, morphological patterns of ovule development within linear fruits are reportedly nonrandom and depend on ovule position. However, little is known about the relationship between nonrandom mating and ovule position within linear fruit. Here, we combined controlled pollen competition experiments and paternity analyses on R. pseudoacacia to better understand nonrandom mating and its connection with ovule position. Molecular determination of siring success showed a significant departure from the expected ratio based on each kind of pollen mixture, suggesting a nonrandom mating. Outcrossed pollen grains, which were strongly favored, produced significantly more progeny than other pollen grains. Paternity analyses further revealed that the distribution of offspring produced by one specific pollen source was also nonrandom within linear fruit. The stylar end, which has a higher probability of maturation, produced a significantly higher number of outcrossed offspring than other offspring, suggesting a correlation between pollen source and ovule position. Our results suggested that a superior ovule position exists within the linear fruit in R. pseudoacacia, and the pollen that was strongly favored often preferentially occupies the ovules that were situated in a superior position, which ensured siring success and facilitated nonrandom mating.
Beijing Key Laboratory of Ornamental Plants Germplasm Innovation &Molecular Breeding; Beijing Laboratory of Urban and Rural Ecological Environment; National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, 100083, China.|National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Cunquan
C
Yuan
National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Yuhan
Y
Sun
National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.|Non-timber Forest Research and Development Center of Chinese Academy of Forestry, Zhengzhou, 450003, China.
Peng
P
Sun
Wenquan Nursery, Beijing Gardening and Greening Bureau, Beijing, 100095, China.
Yunfei
Y
Li
National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Ruiyang
R
Hu
National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Keqi
K
Zhao
National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Jinxing
J
Wang
National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Yun
Y
Li
D000818:Animals; D005638:Fruit / Q000033:anatomy & histology*; D056771:Ovule / Q000033:anatomy & histology*; D011058:Pollen / Q000502:physiology*; D012098:Reproduction; D031301:Robinia / Q000502:physiology*