BREEDING STRUCTURE OF A YUCCA FILAMENTOSA (AGAVACEAE) POPULATION

Area of Science:

• Ecology
• Evolutionary Biology
• Plant-Pollinator Interactions

Background:

• Yucca filamentosa and its pollinator, Tegeticula yuccasella, exemplify coevolved plant-pollinator mutualism.
• Moth behavior suggests limited dispersal, predicting high self-fertilization rates in Y. filamentosa.
• Previous mating system analyses indicated predominantly outcrossed breeding in Y. filamentosa.

Purpose of the Study:

• To investigate effective breeding patterns in natural Y. filamentosa populations.
• To analyze the breeding structure of Y. filamentosa using polymorphic allozyme loci.

Main Methods:

• Investigated 10 polymorphic allozyme loci in a natural Y. filamentosa population.
• Analyzed breeding structure and paternity using genetic markers.
• Quantified pollen movement distances and the number of pollen donors per fruit.

Main Results:

• Y. filamentosa is predominantly outcrossed, with fruits sired by multiple, distinct pollen donors.
• Effective number of pollen donors per fruit ranged from 1.56 to 3.13, indicating some correlated mating.
• Pollen moved between 6 m and 293 m (mean = 118 m), with at least 10% of progeny sired by pollen from outside the population.

Conclusions:

• Findings challenge predictions of limited moth dispersal and high self-fertilization.
• Demonstrates significant pollen movement and outcrossing in Y. filamentosa, supporting effective gene flow.
• Provides insights into the breeding system dynamics within the yucca-yucca moth mutualism.