CHROMOSOMAL DIFFERENTIATION AND SPECIATION IN DIPLOID AVENA. II. THE KARYOTYPE OF A. PILOSA

Abstract

The morphology, cross compatibility and chromosomes of Avena pilosa have been studied, its karyotype established, and designated as Ap . All attempts to hybridize A. pilosa with the other two diploid Avena species have failed, raising to three the number of reproductively isolated diploid species in Avena. The significance of the Ap karyotype in relation to the other two diploid karyotypes (A1 and As) has been discussed on the basis of Levitzky''s concept of karyotype evolution, geographical distribution and reproductive isolation.