EVALUATION OF REGENERATION POTENTIAL OF RICE (ORYZA SATIVA L.) HYBRID MATERIAL

Introduction . In vitro anther culture is an important source of linear material propagation for efficient breeding of rice ( Oryza sativa L.)  in particular due to the reduction of reproduction cycles and the production of homozygous plants. Given the strong variation in the regenerative ability of microspores in different hybrid combinations, it is desirable to cover the maximum number of combinations of hybrids of different generations. Aim. Evaluation of the haploproduction ability of microspores of promising breeding samples of rice. Methods . The anthers of five promising hybrid F 3 populations obtained at the Rice Institute ( Skadovsk ) as a result of hybridization of carriers of various resistance genes to pyriculariosis were used . The inflorescences with microspores at the mid-late stage of development were cut and pretreated for sterilization; the isolated anthers were explanted in Petri dishes on a solid nutrient medium and cultured in the dark until neoplasms were obtained, after which they were transplanted (stage I — after 4-5 weeks). The next transplant event (II stage - after 7-8 weeks) and further cultivation was carried out under lighting to obtain green regenerants. Results . The high sensitivity to in vitro cultivation conditions was shown for the five combinations of F 3 rice hybrids. The rate of neoplasm formation varied from 6.4% (Sirio / УіР4970) to 35% (Sirio / Marshal ). The ability to regenerate in the obtained neoplasms also varied greatly, since most of them were only capable of rhizogenesis, without forming shoots and leaves. Nevertheless the regenerant plants were obtained for each hybrid combination and the proportion of albinos among the total number of regenerants was relatively small. On average about 40% of the regenerants obtained in the culture die at the critical stage of adaptation of regenerated plants to ex vitro conditions; approximately the same number of plants die during the growing process, being unable to give seed generation. Conclusions . The most productive from the point of view of plant formation adapted to ex vitro conditions was the hybrid population F 3 Labelle / Malish (101 adult plants), and the least productive was Sirio / УіР4970 (5 adult plants) among the studied combinations. Thus, by androgenesis in anther culture, 336 plants adapted to ex vitro conditions were obtained.  At the moment, 193 plants are at the earing stage, which is 35.81% of the total number of green regenerants obtained in the culture. Key words: rice; androgenesis in vitro ; callus; regeneration