<p><strong>Objective.</strong> Assessment collection early-season of constant lines germplasm Iodent by morphological and biological parameters, level hypothetical heterosis in nursing crossings and their polymorphism as an integral component of the breeding cycle. <strong>Methods.</strong> Field, mathematical, and statistical. <strong>Results. </strong>The results to the research in the 2013-2015, found that sister hybrids of the least volatile yields grain by years of research were obtained by crossing lines DK744, MS555, DK216. Calculation of correlation coefficients between hypothetical heterosis and genetic distances found no significant association (ɤ=0,118-0,359), and between the yield of nursing hybrids and genetic distances (ɤ=0,167-0,351). Revealed that the line MS555 exceeded the yield of grain line control DK744 to 0,13 t/ha, and had less long period of stairs ̶ flowering 50% heads for 0,3 days. <strong>Conclusions. </strong>Assessment collection early-season of constant lines germplasm Iodent by the complex morphological and biological parameters helped identify the best samples MS555 and DK1274 compared with control DK744. Highlight sister hybrids with significant manifestation of a hypothetical heterosis DK714/195 (142,6%), DK237 (117,7%) DK234 (116,4%), and lowest - MS555 (61,6%), DK744 (78,2%), DK1274 (77,2%). Sister combination between the lines DK744, MS555, DK216 characterized highest stability yield in the years of research.</p>