Usefulness of temperate-adapted maize lines developed by doubled haploid and single-seed descent methods

Authors: GONCALVES DOS SANTOS, LARA - Universidade Federal De Vicosa; VERZEGNAZZI, ANDERSON - Iowa State University; Edwards, Jode; FREI, URSULA - Iowa State University; Boerman, Nicholas; TENELLO ZUFFO, LEANDRO - Universidade Federal De Vicosa; PIRES, LUIZ P - Kenya Wildlife Service; DE LA FUENTE, GERALD - Sesaco; LUBBERSTEDT, THOMAS - Iowa State University

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2022
Publication Date: 3/19/2022
Citation: Goncalves Dos Santos, L., Verzegnazzi, A.L., Edwards, J.W., Frei, U.K., Boerman, N.A., Tenello Zuffo, L., Pires, L.M., De La Fuente, G.N., Lubberstedt, T. 2022. Usefulness of temperate-adapted maize lines developed by doubled haploid and single-seed descent methods. Journal of Theoretical and Applied Genetics. 135:1829-1841. https://doi.org/10.1007/s00122-022-04075-2.
DOI: https://doi.org/10.1007/s00122-022-04075-2

Interpretive Summary: Corn production in the Midwest U.S. is dependent on corn hybrids with very little genetic diversity among them. The lack of genetic diversity among hybrids relied upon for corn production continues to increase the risk of genetic vulnerability. Increasing genetic diversity among corn hybrids almost always leads to reduced productivity making it very difficult to increase genetic diversity among hybrids grown by producers. Continued improvement of modern hybrids also depends on genetic diversity in breeding pools, and hence, lack of diversity in breeding pools also limits that rate of improvement of new hybrids introduced to the market. Researchers in Ames, Iowa, have tested new and more efficient breeding methods to develop new corn lines derived from highly diverse germplasm sources in fewer generations of breeding than traditional breeding methods. The new methods greatly reduce the time required to generate new lines, and thus make the breeding process much more efficient. The ability to generate new, and diverse, lines quickly will enable breeders to much more efficiently test sources of genetic diversity in order to increase diversity among available corn hybrids. These methods will benefit breeders, producers, and consumers of maize through improved cultivars.

Technical Abstract: Adapted exotic maize (Zea mays L.) germplasm, such as BS39, provides a unique opportunity for broadening the genetic base of U.S. Corn Belt germplasm. In vivo doubled haploid (DH) technology has been used to efficiently exploit exotic germplasm. It can help to purge deleterious recessive alleles. The objectives of this study were to determine the usefulness of BS39-derived inbred lines using both SSD and DH methods, to determine the impact of spontaneous as compared to artificial haploid genome doubling on genetic variance among BS39-derived DH lines, and to identify SNP markers associated with agronomic traits among BS39 inbreds monitored at testcross level. We developed two sets of inbred lines directly from BS39 by DH and SSD methods, named BS39_DH and BS39_SSD. Additionally, two sets were derived from a cross between BS39 and A427 (SHGD donor) by DH and SSD methods, named BS39×A427_DH and BS39×A427_SSD, respectively. Grain yield, moisture, plant height, ear height, stalk lodging, and root lodging were measured to estimate genetic parameters. For genome-wide association (GWAS) analysis, inbred lines were genotyped using Genotype-by-Sequencing (GBS) and Diversity Array Technology Sequencing (DArTSeq). Some BS39-derived inbred lines performed better than elite germplasm inbreds and all sets showed significant genetic variance. The presence of spontaneous haploid genome doubling genes did not affect performance of inbred lines. Five SNPs were significant and three of them located within genes related to plant development or abiotic stresses. These results demonstrate the potential of BS39 to add novel alleles to temperate elite germplasm.