Genetic dissection of leaf area by jointing two F_2 : 3 populations in maize (Zea Mays L.)

Abstract

Leaf area (LA) is the most important photosynthesis acceptor, and therefore, size of LA (especially the three ear-leaves) plays a vital role in dry matter accumulation and grain yield in maize. Genetic mechanisms on LA have a theoretical significance for breeding maize with high yield. However, the genetic control of LA remains unknown in maize. In this study, QTL for LA were mapped using two sets of connected F 2 : 3 populations with 229 and 245 families evaluated in two to three environments. Meta-analysis was used to integrate genetic maps and detect QTL across two populations. A total of 38 QTL were detected, 17 in population 1 and 21 in population 2. Thirty-eight QTL were integrated in 13 meta-QTL (mQTL). The novel mQTL2-1 was found to include two initial QTL, and mQTL5-2 to include four initial QTL. Both of them had one of the initial QTL with R 2 over 10%. Therefore, the chromosome regions for these two mQTL with high QTL co-localization might be hot spots for important QTL for LA. Seven key candidate genes controlling related traits of LA were observed to be coincided with five corresponding mQTL, including Arlng1, ArPFL2/OsH1, ArCLF/ArCyCB2;3(LL), ArCYCD3;2, and Osnrl. Especially, Arlng1 was mapped within the important mQTL2-1 interval. Fine mapping for genetic regions of such mQTL is worth further study and could be put into use in marker-assisted breeding. The results provide useful information for further researching and understanding of the molecular mechanisms with regard to LA.

Epistatic and QTL × environment interaction effects on leaf area‐associated traits in maize

“…In two F 2:3 populations in three environments, Ku et al. (2012b) identified 13 mQTL for LA, and five of these mQTL for LA were consistently detected using a set of 245 F 2:3 families derived from the cross Yu82 × D132 in two or three environments. However, only two QTL (qLA4‐1 and qLA4‐2) detected using the RIL population derived from the cross Yu82 × D132 in this study also were detected using the F 2:3 families derived from the same cross.…”

“…The ability to maintain adequate photosynthetic rates at higher plant densities should allow light to penetrate into the ear leaf area resulting in higher grain yield. However, few quantitative trait loci (QTL) mapping studies for LA in maize have been published (Ku et al 2012b). Thus, studying the molecular basis of leaf size has both academic and applied value.…”

“…Guo et al (2015) identified eight meta-QTL (mQTL) associated with the widths of leaves at different positions above the uppermost ear in four recombinant inbred line (RIL) populations. Ku et al (2012b) identified 13 mQTL for leaf area using two sets of connected F 2:3 populations evaluated in two or three environments. The results showed that leaf shape is genetically regulated by numerous genes/QTL for their normal marginal and plate identities.…”

“…However, few quantitative trait loci (QTL) mapping studies for LA in maize have been published (Ku et al. 2012b). Thus, studying the molecular basis of leaf size has both academic and applied value.…”

“…Ku et al. (2012b) identified 13 mQTL for leaf area using two sets of connected F 2:3 populations evaluated in two or three environments. The results showed that leaf shape is genetically regulated by numerous genes/QTL for their normal marginal and plate identities.…”