Genetic composition and heterozygosity of gibberellin-induced 2n gametes evaluated by SSR markers in Populus

The artificial induction of unreduced (2n) gametes, due to first division restitution (FDR) or second division restitution (SDR), is an important method to produce triploids in higher plants. It is crucial to evaluate the genetic composition and heterozygosity transmission of induced 2n gametes with different formation mechanisms.

Here, we produced 110 triploids by pollinating the female inflorescence of Populus alba × P. glandulosa with gibberellin-induced 2n pollen of Populus bolleana. The genetic composition and heterozygosity of the induced 2n pollen were inferred from SSR marker analysis of the triploid offspring, using 27 primer pairs distributed across nine Populus chromosomes. This revealed that, among the 110 hybrid triploids, 70 triploids did originate from FDR-type 2n pollen and the other 40 from SDR-type 2n pollen. The FDR-type and SDR-type 2n pollen transmitted a substantially different level of parental heterozygosity (0.7545 and 0.3167, respectively) in P. bolleana. Additionally, compared with the low coefficient of variation (CV = 12.82%) for heterozygosity transmitted by FDR-type 2n pollen, there was much higher coefficient of variation (CV = 48.82%) for that transmitted by SDR-type 2n pollen.

Our findings provide a valuable reference point for bolstering suitable applications of 2n gametes in future research, and can help foster new strategies of triploid breeding in plants.

Not applicable.