Breeding value of prolific maize varieties with nicking of parental lines

Background. Production of multiple-ear maize varieties is quite complicated because of asynchronous flowering in parents. Solving the problem of flowering asynchrony by breeding methods will allow breeders to improve the yield through increasing the number and quality of ears located lower than the top ears. Among the genetic reserves of the multiple-ear feature in maize are its wild relatives, such as teosinte (Zea mays L. subsp. mexicana (Schrad.) H.H. Iltis (basyonym Euchlaena mexicana Schrad.)) and eastern gamagrass (Tripsacum dactyloides L.).

Materials and methods. Phenological observations were conducted according to conventional procedures. Measurements and records were made on 10 plants and 10 ears in two repetitions. Statistical data processing was performed according to B. A. Dospekhov's technique, while biometric measurements and their description were provided according to the COMECON Unified Classifier. The sterile single-ear maize line GK26M bred at the Lukyanenko Institute of Agriculture was used as a tester. The Chalko teosinte from the VIR collection was the source of multiple-ear feature (i-350969).

Results. The analysis of the lines and their topcrosses helped to systemize all lines into 4 groups according to their ability to transfer the gene of the multiple-ear trait into F1. The research showed the breeding value of the prolific lines that could form more than one ear on a hybrid plant after hybridization with the singleear tester. It is important to select for flowering synchrony between the upper and lower rows of ears. Violation of this principle leads to a disproportion in morphological features of the structure of upper and lower ears, and decreases the productivity and quality of the lower ears.

Conclusion. The studied prolific maize lines developed by involving the Chalko teosinte genome appeared to be effective donors of the multiple-ear feature in crosses with single-ear maize. The developed lines Teo6758 (pk-4352 in the Provisional Catalogue); Teo67662 (pk-4349), Teo67130 (pk-4350), Teo671304 (pk-4353), Teo6740 (pk-4334), Teo674 (pk-4365), Teo674000 (pk-4333), Teo67251 (pk-4354), Teo67252 (pk-4348), Teo6715 (pk-4357), Teo67642 (pk-4359), Teo6767 (pk-4360), Teo6773 (pk-4363), Teo679933 (pk-4347), Teo671302 (pk-4338), Teo71303 (pk-4339), Teo67MP (pk-4342), Teo67143 (pk-4332), as the donors of the prolificacy gene, form multiple-ear hybrids in combinations with singleear testers.

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