Cytogenetic Analysis of Festuca Species and Amphiploids between Festuca mairei and Lolium perenne

Abstract

Intergeneric hybridization between Lolium and Festuca has been an interest of forage and turfgrass breeders because most agronomic and economically important traits found in Lolium and Festuca are complementary. However, low fertility of intergeneric hybrids has often been present and difficult to overcome. Synthesis of amphiploids from F1 hybrids was proven to be an effective way in restoring fertility of these intergenic hybrids. Amphiploids were used as bridging germplasm to improve forage quality and persistence in these two genera. In this report, amphiploids (LLM1M1M2M2) between F. mairei St. Yves. (M1M1M2M2, 2n = 4x = 28) and L. perenne L. (LL, 2n = 2x = 14) were produced from the F1 hybrid (F. mairei × L. perenne) through the treatment of colchicine and dimethyl sulfoxide (DMSO). Cytological analyses of pollen mother cells (PMCs) indicated that the amphiploids were unstable in meiosis with chromosome configurations of 9.75 I + 15.32 II + 0.43 III + 0.10 IV at metaphase I (MI). The pollen potassium iodide (KI) stainability of the amphiploids was 21%, while the F1 had only 0.1% pollen stainability. Interspecific hybrids were made through crosses between F. arundinacea Schreb. (6x) and F. mairei (4x). The pentaploid hybrids (PG1M1G2M2) had mean chromosome configurations of 6.47 I + 13.40 II + 0.30 III + 0.19 IV + 0.01 V at MI, indicating a close genomic relationship between F. arundinacea Schreb. (PPG1G1G2G2) and F. mairei (M1M1M2M2). The amphiploids and pentaploid hybrids were proposed to be used for improving drought persistence of tall fescue with incorporation of genes from drought‐tolerant F. mairei