Combining ability of new maize lines according to grain productivity and its components

The most important indicator of the initial material’s value in breeding for heterosis is its combining ability. The purpose of the current work was to study the combining ability of new self-pollinated maize lines according to grain productivity and its main components. The study was conducted at the FSBSI “ARC “Donskoy”, located in the southern part of the Rostov region with unstable moisture, in 2021–2023. The objects of the studies were 9 new constant self-pollinated maize lines and the line ‘RD 329’, used as a standard. The objects of the studies were also 3 testers, simple maize hybrids ‘Kros 1’, ‘Kros 2’, ‘Kros 3’ and 30 new test-cross hybrids of maize. There have been identified new highly heterotic maize hybrids of practical interest ‘Kros1×Sl 303’ (5.05 t/ha), ‘Kros1×Sl 308’ (4.75 t/ha), ‘Kros1×Sl 309’ (4.84 t/ha). There have been identified new self-pollinated lines ‘Sl 303’ (gi = 0.56), ‘Sl 308’ (gi = 0.43) and ‘Sl 309’ (gi = 0.47) with high combining ability according to the trait ‘grain productivity’ and are recommended for use in programs of hybridization. Self-pollinated lines with high GCA according to grain productivity, as a rule, had higher GCA for such productivity traits as ‘a number of grains per ear’, ‘one ear weight’ and ‘a number of ears per plant’. This contributed to the formation of a large number of grains per ear in test-cross maize hybrids (623–655 pcs.), the formation of ears with a large weight (131–147 g), and the absence of sterile plants in dry conditions. The combining ability according to the trait ‘1000-grain weight’ had no effect on productivity of test-cross hybrids in dry conditions. The use of self-pollinated lines with high values of productivity traits and transmitting high values to hybrids made it possible to develop new productive hybrid combinations.