Original Article

Sexual Plant Reproduction

, Volume 18, Issue 4, pp 187-194

First online:

Pollen–pistil barriers to crossing in maize and teosinte result from incongruity rather than active rejection

  • Jerry L. KermicleAffiliated withLaboratory of Genetics, University of Wisconsin Email author 
  • , Matthew M.S. EvansAffiliated withDepartment of Plant Biology, Carnegie Institution of Washington

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Many popcorn strains cannot be fertilized by pollen of dent and flint strains although the reciprocal crosses are successful. Similarly, plants of some annual teosinte populations can fertilize maize but do not accept its pollen. Single genes or gene complexes govern these two unilateral barriers to crossing. Failure of fertilization could reflect active rejection by the pistil of pollen containing a contrasting allele (incompatibility). Alternatively, the pistil could require presence of a matching allele in pollen (congruity). To distinguish between these possibilities genetically, the receptivity to pollen having both alleles was determined. If there is active rejection, heteroallelic pollen would not be accepted; if presence of a matching allele is required, heteroallelic pollen would be accepted. In both the popcorn and teosinte crossing barrier systems, heteroallelic pollen functioned, consistent with the congruity model.


Cross incompatibility Incongruity Pollen–pistil interaction Zea mays L