Impact of donor QTL on grain yield and gray leaf spot of four recombinant inbred lines of maize

Abstract

Improved maize (Zea mays L.) hybrids must possess both high grain yield (GY) and disease resistance for commercial production. Four recombinant inbred lines (RILs) with resistance to a gray leaf spot (GLS, caused by Cercospora zeae-maydis Tehon & E. Y. Daniels) were developed from a cross between YML32 (resistant) and Q11 (susceptible). Three RILs (RL1_1, RL1_2, and RL2_1) contained a resistance-carrying DNA segment (RDNAS); the fourth RIL (RL2_2) did not possess RDNAS. Five testers (four RILs and Q11, male) were crossed with 13 maize lines (female) of three known heterotic groups and tested in 2016 (2016 experiment; results published in 2018). In the current study, we crossed the 21 lines (female, 13 previous lines plus eight new lines, 2018 experiment) with the same five testers (male). The objectives were (a) to determine if GY of the testcrosses, especially with RIL2_2, and GY heterosis were improved over the testcrosses with Q11, and (b) to compare the results of the 2018 and 2016 experiments to know if different years and/or additional maize lines affected GY. The GY of the crosses with the four RILs and the GY heterosis of testcrosses were improved over the crosses with Q11 in the 2018 experiment, mainly because of low GLS score. RIL2_2, lacking the RDNAS, possessed GLS resistance genes different from those in the three RDNAS-carrying RILs. We concluded that at least 20 lines representing different heterotic groups should be crossed with new RILs and that a second year of testing would be desirable to obtain reliable estimates of GY of the new RILs and to identify new high-yielding hybrids.

Identification of Candidate QTLs and Genes for Ear Diameter by Multi-Parent Population in Maize

“…This model offers significant advantages, as there is a large genetic difference between the three populations, allowing for targeted genetic improvements between the two groups without affecting the hybrid advantage between populations. This approach greatly improves breeding efficiency [ 33 ], and, using the “three heterotic group” pattern, has resulted in the successful breeding of excellent hybrids [ 30 , 31 , 32 , 34 , 63 ]. Among these hybrids, three excellent hybrids were selected from the multi-parent population parents, namely Yunrui88 (TRL02×Ye107/Reid×nonReid), Desan5 (D39×Ye107/Suwan1×Reid), and Yunrui62 (TRL02×D39/Suwan1×nonReid), all of which exhibited high GY and GY_MPH ( Table 4 ).…”

Putative genes for resistance to gray leaf spot of maize based on genomic resequencing using recombinant inbred lines

“…The four RILs were the same as used by the research group of Xingming Fan at the Yunnan Academy of Agricultural Sciences (Jiang et al., 2020; Li et al., 2018). The RILs were developed via marker‐assisted selection from the backcross population (YML32× Q11) × Q11.…”

“…Durable disease resistance is a quantitatively inherited trait because it is regulated by multiple loci (Wisser et al., 2006). Thus, the introgression of quantitative trait loci (QTL) for resistance to GLS from donors into elite maize germplasm is essential for developing GLS‐resistant cultivars, and progress has been made in this direction (Jiang et al., 2020).…”

High-density mapping for gray leaf spot resistance using two related tropical maize recombinant inbred line populations

“…Although there are many putative QTL located on different chromosomal loci in maize, none of the genes underlying them have been cloned. Maize lines originated in Suwan 1 (tropical germplasms) show good combining ability with Reid or non-Reid (temperate germplasms) heterotic groups and adopting these good combiners can remarkably improve maize breeding e ciency, especially for grain yield in southwestern China [23,24], tropical GLS-resistant germplasm resources have better application value and mean in breeding under abiotic and biotic stress [10,25]. Thus, screening additional germplasm, especially tropical maize germplasm, is of great signi cance for mining GLS resistance QTL.…”