Morphological variability of haploid plants and doubled haploids of rice obtained on one callus line in anther culture in vitro was studied. The work was carried out on rice plants Oryza sativa L. subspecies japonica Kato varietу Cascade. Regenerant plants of one callus line obtained from one rice anther (four in total) were divided into two or three groups of 20-30 plants, depending on the sample size in order of their differentiation on callus and transplantation on the rooting medium. Two

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... lus lines (15.1 and 18.1) formed half of the haploids, half of the doubled haploids, and two other callus lines (5.1 and 7.2) numerous haploids. On callus lines with numerous haploids (5.1 and 7.2), as the regenant number increases, the size of plants decreases (plant height, number of flowers on the main panicle, number of panicles). On the lines 15.1 and 18.1 between groups of haploids and between groups of doubled haploids statistically significant differences absent. In breeding purposes for the induced doubling of the number of chromosomes in haploid regenerants with antitubulin substances such as colchicine, it is advisable to use plants that form on callus among the first. Between haploids of four callus lines and doubled haploids of two callus lines, statistically significant differences (at p=0.001) were revealed using the Hotelling's T2-criterion, calculated for the whole complex of biometric features. Haploids of different lines differed in three or four of them, doubled haploids on three of the five signs (length of panicle, productive bushiness and plant height). Varieties of interest to breeders may be improved by anther culture in vitro.