On the Role of Xenogamy in the Development of Life Strategy for Fragaria vesca L. in Western Siberia

Abstract

A combination of xenogamy and autogamy in the breeding system is typical for natural Fragaria vesca L. populations. A natural experiment has been conducted to clarify the portion of xenogamy. During flowering, the plants of inbred line no. 08-2, marked by recessive c allele (light yellow colored berry), are placed in native populations of wood strawberry of two different biotopes. The plants of the native population form only red berries (a dominant trait). After the end of flowering period, the berries are collected from plants of line no. 08-2, the seeds are isolated, and seedlings are obtained. Genetic analysis by the “;berry color” marker sign is conducted among these seedlings. In the case of autogamy, the seed progenies have a light yellow berry; in the case of xenogamy, they have berries with a red skin (as a result of infusion of the pollen with dominant C allele from native F. vesca populations by pollinator insects). Genetic analysis demonstrates significant differences in regards to the ratio of crossing systems (autogamy and xenogamy) in a series of experimental plants. However, the integral value of xenogamy achieved in the seed progeny is close in both natural F. vesca populations (21%), while the average portion of autogamy is 79%. We assume that the indicated ratio of crossing systems for the F. vesca populations is optimal to maintain population heterogeneity and develop their life strategy under growth conditions. During xenogamy, a certain portion of heterotic heterozygotes able to develop new habitats (fulfilling the explerent strategy) is maintained in the population. Autogamy contributes to an increase in the portion of inbred genotypes (patients). Thus, the opportunities to achieve any three type of strategies (violents, patients, and explerents) are created for the F. vesca depending on the plant living conditions.