A novel source of genetic variation in ryegrasses (Lolium multiflorum, L. perenne)

Abstract

A short period of colchicine treatment at the seedling stage induces changes in the capacity for tillering, vegetative growth and flowering time in inbred lines of Lolium multiflorum. The changes are heritable and are observable in the selfed-seed generation following that in which the treatment was given. Information is also given to confirm such changes in an additional ten inbred lines of Lolium perenne. INTRO D U CTI ONIn previous studies in which we have used colchicine as a chromosome doubling agent to produce tetraploids from diploid inbred lines of perennial ryegrass (Lolium perenne) we have observed that the colchichine treatment itself induces heritable changes in the undoubled diploids that were used as controls (Hague and Jones, 1987;Francis and Jones, 1989). The changes involved characters of agronomic significance such as tiller number and fresh and dry weight of leaf material. In the lines investigated so far we have found that these chages varied in their magnitude between lines, and that they were directional in that vegetative production was either increased or else the differences between the treated and untreated controls were nonsignificant. The changes were not random. We have further demonstrated that in perennial ryegrass these coichicine-induced changes are heritable, and that they are transmitted undiminished through a selfed-seed generation (Francis and Jones, 1989). In this publication we present new results for coichicine-induced heritable variations in Italian reygrass (L. multiflorum), and we also confirm the results for L. perenne using ten additional inbred lines that have not been previously studied. MATERIALS AND METHODSThe Italian ryegrass lines originate from experimental material produced by Professor G. Kobabe, University of Göttingen and the perennial ryegrass lines are from the inbred material which was originally produced at Hohenheim by Utz and Oettler (1978). The L. perenne lines have their origin in the German ryegrass varieties Odengrün and Odenwãlder. In both cases it can be assumed that we are dealing with pure breeding homozygous lines.Seeds from ten lines of Italian ryegrass and ten lines of perennial ryegrass were "sown" on moist filter paper in petri dishes in October 1986. The petri dishes were placed in a refrigerator at 4°C for one week to aid germination. When the seedlings had grown to 2-3 cm some of them were treated by total immersion in O2 per cent aqueous colchicine for 3 hrs at room temperature, and others were immersed in water as the untreated controls. After washing and recovery from treatment the two groups of seedlings were planted in John Innes Compost and grown on in plastic multitrays in a heated greenhouse for two weeks. The survival rate of the coichicine-treated material was of the order of 65 per cent.At 7 weeks of age the plants were transferred to 5-inch pots in John Innes Compost and grown on to flowering in an unheated glasshouse. Flowering occurred in May-June 1987 and all of the plants were then bagged for self-pollination. The co...

Colchicine-induced heritable variation in cell size and chloroplast numbers in leaf mesophyll cells of diploid ryegrass (Lolium perenne L.)

“…The results described in this paper augment our earlier findings on colchicine-induced heritable changes in Lolium perenne (Hague & Jones, 1987 ;Francis & Jones, 1989 ;Hassan et al ., 1989) . To the established effects of increases in tiller number, increases in fresh and dry weight of leaves, and increases in the length of the mature inflorescence and in the number of spikelets per inflorescence, we can now add two more characters which show the induced heritable response .…”

“…Observations from a second series of experiments using a different set of inbred lines from L . perenne, and also a set of inbred lines of Italian ryegrass (Lolium multiflorum L.), confirm the heritable nature of the effects in CT1 generation plants (Hassan et al ., 1989) .…”

Colchicine‐induced variation of cell size and chloroplast number in leaf mesophyll of rice

“…Similar types of induced change in ryegrasses are heritable and have also been observed in the C 1 plants grown from seed produced by sel®ng the C 0 (Francis and Jones 1989). Con®rmation of these induced heritable changes has been obtained in another series of experiments using C 1 plants from lines of both Lolium perenne and Lolium multi¯orum (Hassan et al 1989). The main ®ndings for the agronomic characters were that colchicine induced an increase in tiller number and fresh weight of leaves of the order of 25%, averaged over several lines, and that the changes were directional in the lines involved.…”

“…Colchicine treatment applied to seedlings has been shown to aect a wide range of quantitative characters in both perennial and Italian ryegrass (Hague and Jones 1987, Francis and Jones 1989, Hassan et al 1989, Francis et al 1990, Hassan and Jones 1994, 1995 and in rice plants (Hassan et al 1993). In general, the eects of treatment are positive and directional such that colchicine produces more, and more quickly as judged by heading date.…”

Long-range effects of colchicine sensitivity on meiosis in Lolium multiflorum L. (Italian ryegrass)

“…This is the same material as that used in earlier experiments on coichicine-induced variation in agronomic (Hassan et a!., 1989) and cell characters (Hassan eta!., 1991 Chiasma frequency and distribution patterns at metaphase I (Ml) were recorded for a sample of 20…”