Selection of early ripening corn lines with positive response on plant overcrowding

The studies were conducted to select starting material suitable for the selection of early ripening corn grain hybrids. The research was conducted in the Voronezh branch of the All-Russian Research Institute of Corn in 2018 and 2019. The reaction of 8 early-ripe (FAO 140-160) self-pollinated corn lines to the conditions of crops overcrowding according to the results of 28 diallel hybrids testing (F1) was studied. The test was carried out at overcrowding from the optimal density 60 to 90 thousand/ha with the interval of 10 thousand/ha. Significant influence of the increased density of plants standing on the number of spikes on 100 plants, yield, harvesting moisture of grain and selection index of studied group of diallel (F1) hybrids has been established. Lines B 305/70, B 305/1768 and B 50-4/2088 were identified, which contribute to the production of hybrids with a minimum number of infertile plants when overcrowed to 90 thousand/ha. Grain hybrids with the participation of lines B 50-4/2071 and B 50-4/2085 (0.7-0.9%) increase the moisture of the grain to the least extent, while the lines B 50-4/2088 and B 50-9/1791 (1.8-2.2%) increase the moisture of the grain most of all. Hybrids with lines B 50-4/2071, B 50-4/2074, B 50-4/2085 and B 50-4/2088 showed a high yield with a maximum density of 90 thousand/ha. Line B 305/70 allows the production of hybrids with a high yield in sowing in a wide range of densities. Taking into account the optimal combination in the genotype yield and harvesting moisture of the grain, promising lines B 50-4/2071 and B 50-4/2085 are identified, which contribute to the production of hybrids with high selection indices when crops are overcrowded up to 90 thousand/ha, recommended for inclusion in programs for the creation of early ripening grain hybrids.