Influence of maize plant stand density on seed productivity of parent components of Zea mays L. hybrids

Purpose. To investigate the effect of maize plant stand density on seed productivity of the parent components of Zea mays L. hybrids under the conditions of the Forest-Steppe of Ukraine.Methods. Field, laboratory, identification method: morphological description, statistical, estimated.Results. One of the criteria for yield formation is the optimal plant density per unit area. During the 2014–2017 period, three values of plant density were studied for simple hybrids (75,000, 85,000 and 95,000 plants per hectare), and three for parent components: self-pollinated lines (85, 95 and 105 thousand plants per hectare). Increasing plant density led to 9.7–13.0% increase in the height of the place of attachment of the productive cob. Under high plant density, productivity (the number of full cobs), cob weight and 1000-kernel weight reduced. The early-ripening hybrid ‘Rist SV’ provided a relatively high yield of 133.7 centners/ha with low moisture content at the harvesting at a density of 75,000 plants per hectare, which exceeded the yield in the treatment with a plant density of 85,000 and 95,000 plants per hectare by 9.1 and 14.4 centners /ha, respectively. A mid-ripening hybrid ‘Rushnyk SV’ provided the highest yield of 124.7 centners/ha at a plant density of 75,000 plants per hectare, which is by 3.2 and 6.2 centners/ha higher than in the treatments with 85,000 and 95,000 plants per hectare, respectively. The mid-early-ripening hybrid ‘Richka S’ showed the highest yield of 132.3 centner/ha at the plant density of 95 thousand plants per hectare which exceeded by 8.1 and 4.2 centner/ha the treatments with a plant density of 75,000 and 85,000 plants per hectare, respectively. Among the parent components of the hybrids, the self-pollinated early-ripening line ‘UR 9 zC’ provided the highest yield of 50.7 centners/ha at the plant density of 105,000 plants per hectare, which exceeded the yields at the plant density of 85,000 and 95,000 plants per hectare by 2.4 and 1.3 centners/ha, respectively. In the mid-ripening line ‘UR 331 SV’, the highest yield of 63.1 centners/ha was obtained in a treatment with plant density of 105,000 plants per hectare, which by 6.3 centners/ha exceeded the yield in the treatment with 85,000 plants per hectare and by 4.4 centner/ha in the treatment with 95,000 plants per hectare). The late-ripening line ‘UR 12 Zc’ provided the highest yield of 73.7 centners/ha at the plant density of 105,000 plant per hectare, which is higher by 7.4 (85,000 plants per hectare) and the yield of 6.7 centners/ha (95,000 plants per hectare).Conclusions. The results of the research demonstrate that the plant density of corn hybrids and self-pollinated lines affects seed productivity, depending on the group of the maturity of the parent components of the Zea mays L. hybrids under the conditions of the Forest-Steppe of Ukraine.