Cytoplasmatically inheritance in determination of rice milling quality

Baibossynova S.M., PhD in Agricultural Science

Kazakh Rice Growing Research Institute. Corp LTD

Cytoplasmatically or extrachromosomal (extranuclear) inheritance - heredity, under which issue to genetic information is connected with localized in cytoplasms (plasmotype) hereditary element plasmogenes.

The study cytoplasmatically inheritance at present not less actual, than studies chromosomal heredity. Importance to their consists in that this with plasmotype can be linked the much different biological properties since through cytoplasmatic is realized of the genetic potential genome in plants ontogeny.

Extrachromosomal heredity of rice influences on immunity [1], salinity tolerance [2], cold tolerance [3], tolerance for transient low light stress in rice [4].

We studied the influence of cytoplasmically inheritance on the leading indexess of rice milling quality: hull content, translucent, cracking endosperm, the percentage of polished rice, percentage of head rice. The material of the study - an isogenic analogues 12 varieties (BC₁₅) and 24 hybrids topcrossing with substituted cytoplasm WA and Gam types. The donor alien plasmotype were wild type of the rice Oryza rufipogon (WA type) and African variety Gambiaca (Gam type).

The most direct effect plasmogenes noted at analysis translucent endosperm. High were also specific effects interaction "genotype x plasmotype". Maximum their influences is noted on phenotype variability of the percentage of polished rice, percentage of head rice, cracking endosperm. So, example, WA cytoplasm realistically reduced translucent and percentage of polished rice of the variety “Aist”, but positive effect existed beside variety “Prima”. In comparison with source varieties and their alloplasmatically isogenic analogue on cracking endosperm has shown presence cytoplasmic heterosis (the variety “Prikubanskiy”), depression (the “Aist”) and absence plasmotype sensitive gene control character (“Prima”, “VNIIR 1390” and others.).

Variability of the character quality typical and for cytoplasmically differing hybrids of topcrosses. So, the general reduction to intensities of the processes cracking endosperm hybrids with WA plasmotype promoted increase the percentage of head rice in contrast with Gam analogues. Will revealed essential dependency to expression chromosomal gene from plasmotype hybrids (the table).

Table. The analysis of the interaction nuclear genes with cytoplasm hybrids.

Character	Interactions		Standard error
	additive genes x cytoplasm	nonadditive gene x cytoplasm
Grain shape	0,102	0,012	0,0015
Hull content	2,06	0,41	0,14
Translucent	175,89	45,18	1,15
Cracking	11,71	5,25	0,38
Percentage of polished rice	2,19	0,25	0,13
Percentage of head rice	9,92	5,48	0,11

Obviously, that character of the genetic control main properties rice milling quality is predestined not only nuclear genomes, but also cytoplasmatically background of the plant, i.e. the whole combining hereditary factors.

Will discovered tendency to variability hereditary determination under influence plasmotype, conditioned from specialty of the characters. For example, WA-type cytoplasm greatly intensified the nonadditive of the interactions genes, determination general percentage of polished rice, percentage whole-grain rice, cracking endosperm i.e. properties, characterizing stability of the rice-grain to crushing at conversion and defining final productive productivity of the variety. But, on the other hand, hybrids with this plasmotype differed more expressing in contrast with Gam analogue additive effect genes, control translucent i.e. index to general consistency endosperm, phenotype which is defined by shape, size, structure and relation of the starched granules.

Thereby, extrachromosomic hereditary element cell (plasmotype) belongs to the important role in control rice milling quality. These phenomena necessary constantly to take into account in theoretical and applied breeding studies.

Literature

1. Durgapal J.C. "Albino" mutation in rice bacterial blight pathogen // Curr. Sci. India - 1996. - 70,1. - p.15

2. Mishra B., Akbar M. Genetics of salinity tolerance and ionic uptake in rice // Intern. Rice Res. Notes - 1996. - 21,1. - p.38-39

3. Ratho S.N. Pradhan S.B. Cytoplasmically control cold tolerance in a cytoplasmic-genetic male sterile line of rice // Euphytica - 1991. - 58,3. - p.241-244

4. Chen Y.F., Li C.G. Epigenetic control of tolerance for transient low light stress in rice // Intern. Rice Res.Notes - 1996. - 21,1. - p.39-40