Single cross (SC) hybrids of maize became a more widely used type in modern agriculture, that generates a superior expression of heterosis for grain yield, positive reaction to higher plant densities and nitrogen applications. An other important characteristic of SC hybrids is the perfect uniformity of plants. In Moldova, where seed production of early maize is affected by drought, modified single cross hybrids (MSC) would be an efficient solution. MSC hybrids are produced using related lines crosses for female parent, more vigorous and productive that inbred lines per se. Our investigations indicated that inbreds with 30-60% of genetic diversity index (DG) and phenotypic similarity make competitive and uniform hybrids. Hybrid Rosmold 202MRf, registered in Rusia since 2012, has been created with female parent MKP60cmsM x MKP61. Both inbred lines were developed from initial material with a common progenitor from Reid Iodent germplasm group and genetic distance (DG = 22,1%) indicating a close similarity. For a period of 7 years this related cross was statistically proved to be more productive for grain yield–4,79t/ha in comparison with the best line MKP60 – 3,98t/ha. It has been considerably higher for germination percentage of seeds in cold soil, uniform emergence and development of normal seedlings under a wide range of field condition, more vigorous growth of plants. Sizing of kernels into uniform standard lots (fractions) based on width, thickness and length demonstrated that inbreds have shorter seeds and the percent of discarded small kernels is higher, compared with related cross. This morphological characteristic of kernels from related cross permit to achieve commercial seeds with acceptable sizes (fraction nr.2 and nr.3) more solicited by customers. The second MSC hybrid of maize Bemo 203 developed with the same female parent has been registered in Belarus since 2015 year. At present inbred line MKP60cmsM has been changed by MKP601cmsM, derived from the next cycle of cumulative selection. It is used in related crosses with MKP61, MKP611, MKP612, and distanced genetically in interval 28-42%. Experimental dates from hybrids testing trails indicate a high yielding capacity and relative uniformity of plants between testcrosses of MKP63cmsMxMKP601 as female parent. Components of this related cross are genetically more distanced (DG>70%) and difference between them for flowering period is 5 days. This related cross was used as seed parent in a new maize hybrid Farmec transferred since 2018 for official state testing in Belarus. The studies of inbred lines from different heterotic groups indicated that Reid Iodent germplasm has been better adapted to the natural conditions of Moldova and is more preferable as female parent Related crosses formed in average 5,68t/ha grain in comparison with the 3,51t/ha for inbred lines from Reid Iodent heterotic group. The MSC hybrids in generally were closely to SC for grain yield and uniformity increasing significant the profitability of seed production.