Development of an Efficient Plant Regeneration System from Apomictic and Sexual Seeds of Guinea Grass (Panicum maximum) | Chapter 8 | Research Perspective on Biological Science Vol. 1

Guinea grass (Panicum maximum) is an important tropical forage crop. It is represented in nature by both of the tetraploid biotypes that can reproduce through apomixis, and the sexual one. If this trait can be applied, it is expected to be an epoch-making breeding method, such as significantly reducing the cost of seed production by fixing first-generation hybrids, significantly shortening the breeding period by fixing promising strains in the middle of breeding, and converting vegetatively propagated plants to seed-propagated plants. The authors have captured a candidate gene, ASG-1, from apomictic guinea grass.　For analysis of apomixis genes, as the first step, an efficient and simple plant regeneration system has been established using callus from apomictic and sexual seeds of guinea grass (Panicum maximum). This study was conducted at the Miyakonojo Campus of Minami Kyushu University in Miyakonojo City, Japan, located at 31 degrees north latitude. The best basic medium for callus formation from mature seeds of guinea grass was selected, and then, the best combinations of growth regulators on different media were selected for plant regeneration by indirect organogenesis. Guinea grass accessions of sexual and apomict seeds were used for culture. Seeds sterilized were cultured in Murashige and Skoog (1962) medium (MS) and in that proposed by Chu et al. (1975) (N6D) for callus formation. The best medium and the effects of L-proline and growth regulators’ type and concentrations on callus formation and plant regeneration in 3 accessions were examined, respectively. After the plantlets rooted in MS hormone-free medium, the complete plants were planted in pots for hardening. As a result, N6D medium has given better rates for callus formation, that is, 97.1% in sexual N68/96-8-o-5, and 91.7% and 84.6% in apomict N68/96-8-o-11 and ‘Natsukaze’, respectively. MS medium with 0.2 mg/l of Kinetin has given the best rate of plant regeneration among the 4 kinds of media. For each material, the best results were obtained on MS with 0.2 mg/l of Kinetin for N68/96-8-o-5, and MS with 2.0 mg/l of L-proline and 0.2 mg/l of Kinetin for ‘Natsukaze’. After hardening of the regenerated plants in soil, 100% of survival rates were obtained, and showed normal growth compared with the plants derived from seeds. As described above, it was established, as the first case, an efficient and simple plant regeneration system by using callus from apomictic and sexual seeds of guinea grass for analysis of apomixis genes, consisting of analysis of the best media, L-proline usages and phytohormone combinations for callus formation, plant regeneration and hardening in different stages, respectively. This finding provides important information not only for sexual but also for apomictic plants in constructing a plant regeneration system from calli derived from mature seeds.

 

Author (s) Details

 

Chen Lanzhuang
Faculty of Environmental and Horticultural Science, Minami Kyushu University, 3764-1, Tatenocho, Miyakonojo City, Miyazaki, 885-0035, Japan.

Nishimura Yoshiko
Faculty of Environmental and Horticultural Science, Minami Kyushu University, 3764-1, Tatenocho, Miyakonojo City, Miyazaki, 885-0035, Japan

 

Umeki Kazuma
Faculty of Environmental and Horticultural Science, Minami Kyushu University, 3764-1, Tatenocho, Miyakonojo City, Miyazaki, 885-0035, Japan.

 

Zhang Jun
Qinghai Academy of Animal Science and Veterinary Medicine, Xining, Qinghai, 810016, China.

 

Xu Chengti
Qinghai Academy of Animal Science and Veterinary Medicine, Xining, Qinghai, 810016, China.

 

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