HYBRIDS AND INDUCED AMPHIPLOIDS OF ELYMUS CANADENSIS X AGROPYRON LIBANOTICUM

Abstract

North American Elymus canadensis L., 2n = 28, and Asian Agropyron libanoticum Hack., 2n = 14, crossed with ease and yielded vigorous but sterile F1 hybrids, 2n = 21. Chromosome pairing in the hybrids averaged 9.47I, 5.38II, and 0.26III in 150 metaphase‐I cells. One genome of E. canadensis is more or less homologous with the A. libanoticum genome. Treatment of the F1 hybrids with colchicine produced 42‐chromosome amphiploids, C0, which were advanced through two seed generations, C1 and C2. More than half of the metaphase‐I cells in the C0 amphiploids contained 21II; and average associations were 1.09I, 20.16II, 0.07III, and 0.09IV in 116 cells. Meiosis became increasingly irregular beyond metaphase‐I; nevertheless, the C0 amphiploids produced 68% stainable pollen and averaged 0.75 seed per spikelet. Multivalent frequencies increased in advanced generations, and the C2 amphiploids averaged 1.11I, 19.00II, 0.23III, and 0.55IV in 100 metaphase‐I cells. Meiosis was essentially regular in the C1 and C2 amphiploids beyond metaphase I, and the C2 amphiploids averaged 73% stainable pollen and 2.28 seeds per spikelet. The amphiploids have an excellent chance of developing into a meiotically stable, fertile, new species. Forage characteristics of the amphiploids indicate that they have considerable economic potential as a forage grass.