Identification of QTL for ear row number and two-ranked versus many-ranked ear in maize across four environments

Abstract

Ear row number (ERN) is not only a key trait involved in maize (Zea mays L.) evolution but also an important component directly related to grain yield. In this report, 325 recombinant inbred lines (RILs, F 6:7 ) derived from a cross between B73 with 16 rows and SICAU1212 with four rows (two-ranked with two rows per rank) were utilized to detect quantitative trait loci (QTL) associated with ERN and two-ranked versus many-ranked ears (TR). Compared to modern maize that formed approximately 8-20 rows, SICAU1212 with four rows was the extreme case. A total of 12 and 8 QTLs were associated with ERN and TR across four environments through single-environment mapping, respectively. Each QTL responsible for ERN explained 2.33-21.28 % of the phenotypic variation. And the TR variation contributed by individual TR QTL ranged from 2.09 to 12.99 %. Notably, only three QTLs, qERN2-1 (bin 2.02), qERN8-1 (bin 8.02) and qERN8-2 (bin 8.04), were consistently detected in each environment and by joint analysis among all environments, which simultaneously influenced ERN and TR. One of the three QTLs, qERN8-1 was also identified as interacting with environment. In addition, nine pairs of significant epistatic interactions (two for ERN and seven for TR) were detected among all QTLs. The epistasis between qTR2-1 and qTR8-1 was consistent in most environments. This present study may provide the understanding of the genetic basis of ERN and TR and a foundation for further fine-mapping of these common QTLs.

Identification of QTL for maize grain yield and kernel-related traits

“…One pair of epistatic interaction involved in region near qHKW2-1 has been identified for GY under water-stressed conditions . Stable epistatic interactions involved in bin 2.03 region were detected for kernel row number in different environments (Cai et al 2014;Yang et al 2015). Sa et al (2015) showed that genetic interactions involved in bin 2.03 region were associated with plant height and HKW.…”

Detection of quantitative trait loci for ear row number in F2 populations of maize

“…ERN is one of the key traits that distinguish maize and teosinte (Doebley, 2004). QTL mapping has been conducted in many studies, and a large number of QTLs have been identified for ERN across generations and environments in all10 maize chromosomes (Doebley et al, 1990;Doebley andStec, 1991, 1993;Veldboom and Lee, 1994;Austin and Lee, 1996;Szabó and Burr, 1996;Upadyayula et al, 2006;Yan et al, 2006;Briggs et al, 2007;Li et al, 2007;Guo et al, 2008;Karen Sabadin et al, 2008;Li et al, 2011;Lu et al, 2011;Cai et al, 2014;Lemmon and Doebley, 2014;Li et al, 2014;Tian et al, 2014;Yang et al, 2015). In this study, three QTLs (qERN2-1, qERN4-2, and qERN8-1) were consistently associated with ERN.…”

“…The first QTL, qERN2-1 (bin 2.02), was also located onthe short segment of chromosome 2, indicating a potential QTL region near qERN2-1 that may not only play a novel role in affecting ERN during maize domestication (Doebley andStec, 1991, 1993), but may also be associated with ERN during later improvement processes. The second QTL (qERN4-2 at bin 4.08) significantly affects ERN (Austin and Lee, 1996;Li et al, 2011;Lu et al, 2011;Yang et al, 2015). In the genetic region of bin 4.08, one major QTL for ERN has been identified in an F 2:3 population, and explained the largest percentage (16.4%) of ERN variation (Cai et al, 2014).…”

“…With the rapid development of molecular genetic marker technology and quantitative genetics, segregation populationshave been used to detect QTLs for ERN, and have contributed to maize domestication and diversification (Doebley and Stec, 1991;Lauter and Doebley, 2002;Li et al, 2011;Lu et al, 2011;Lemmon and Doebley, 2014;Li et al, 2014;Yang et al, 2015). The most consistent result obtained from previous studies is that certain regions on the short segment of chromosome 2 have a large effect on ERN during domestication.…”

Genetic architecture of the maize kernel row number revealed by combining QTL mapping using a high-density genetic map and bulked segregant RNA sequencing

“…These traits are quantitatively inherited and influenced by genotypes, environments, and environment-by-genotype interactions. The KRN significantly contributes to grain yield and has the highest broad-sense heritability ( H 2 ) among the three components [2, 3]. Therefore, the investigation into the genetic architecture underlying KRN is helpful not only for understanding the genetic mechanisms underlying ear development but also for improving the maize grain yield.…”