Identification of interspecific barriers in the genus Lotus.
| Authors | |
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| Year of publication | 2005 |
| Type | Article in Proceedings |
| Conference | Acta Biologica Cracoviensia, series Botanica, 47 suppl. 1 |
| MU Faculty or unit | |
| Citation | |
| Field | Plant cultivation |
| Keywords | Lotus; interspecific barriers; clearing treatment |
| Description | The genus Lotus is a large group comprising approximately 200 species. Lotus corniculatus is a dehiscent species with an indeterminated growth habit. It is a valuable forage species exhibiting several advantageous characteristics, such as high nutritive value, wide adaptation to soil, pH, and moisture, and low bloat hazard. However, its use has been somewhat restricted because of high seed costs. Pod shattering has been a major problem as seed loss is high due to the continuous flowering and time of pod maturity. Shattering resistance is a character of high heritability and in Lotus is considered to be controlled by more than one gene. Classical breeding approaches to reduce shattering through recurrent selection were unsuccessful (Grant 1996). Some species of Lotus reported to be indehiscent, L. conimbricensis, L. uliginosus and L. ornithopodioides, could be potential sources of genes conferred pod indehiscence. Natural interspecific hybridization does not appear in the genus Lotus. There are pre- and post-fertilization barriers of crossability. One of the pre-fertilization barriers is the incapability of pollen to germinate on the foreign stigma and the incapability of pollen tubes to grow through the style. Post-fertilization barriers cover defects in the endosperm and embryo development. Interspecific hybridization has been carried out successfully in this genus using embryo culture procedures (ODonoughue and Grant 1988; Sharma et al. 1996). The aim of our research study is determination of barriers of crossability after interspecific hybridization. An interspecific hybridization programme was undertaken involving the nonshattering species Lotus conimbricensis (2n = 12), L. uliginosus (2n = 12, 14), L. ornithopodioides (2n = 14), and they were crossed with Lotus corniculatus (2n = 24). To study the pre-fertilization barriers, callose in growing pollen tubes were stained by aniline blue. To investigate the role of post-fertilization barriers, hybrid embryo viability was traced by a clearing treatment of immature seed using chloral hydrate (Mayer et al., 1993) after modification. |
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