Isozyme Variation in Avena sterilis L. Collected in Turkey

The National Small Grains (NSG) collection of Avena sterilis L. is an important germplasm resource for cultivated oat (A. sativa L. and A. byzantina C. Koch) improvement. Complete evaluation and utilization of the almost 7000 accessions will be protracted. In the interim, new accessions will be acquired. Previous studies showed that Turkish accessions of A. sterilis exhibited a broad array of isozyme phenotypes found in the wild collection and in over 400 cultivated accessions. The objectives of this research were (i) to determine if recent Turkish acquisitions of A. sterilis (Forsberg‐Simons collections of 1986) have contributed additional isozyme variation to that already in storage and (ii) to illustrate relationships among Turkish A. sterilis and cultivated germplasm. Zymogram phenotypes of 341 A. sterilis and 405 cultivated samples were recorded for 13 enzyme systems. The ll5‐plant sample from the Forsberg‐Simons collection included six phenotypes not previously observed in Turkish accessions in the NSG collection. Cluster analysis suggested that approximately 40% of the Forsberg‐Simons acquisitions differed from much of the existing NSG Turkish accessions. Both local and regional diversity occurred within A. sterilis germplasm. Isozyme patterns in cultivated germplasm were most similar to collections of A. sterilis with a wide geographical distribution.