Zhizhai Liu

Stability of QTL Across Environments and QTL-by-Environment Interactions for Plant and Ear Height in Maize

Abstract Better understanding of genotype-by-environment interaction (GEI) is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments. To elucidate the genetic basis of the plant and ear height, 2 F 2:3 populations were derived from the crosses of Qi 319 × Huangzaosi (Q/H) and Ye 478 × Huangzaosi (Y/H) with 230 and 235 families, respectively, and their parents were evaluated under 3 diverse environments in Henan, Beijing, and Xinjiang, China during the year of 2007 and 2008, and all the lines were also evaluated under water stress environment. The mapping results showed that a total of 21 and 12 QTLs were identified for plant height in the Q/H and Y/H population, respectively, and 24 and 13 QTLs for ear height, respectively. About 56 and 73% of the QTLs for 2 traits did not present significant QTL-by-environment interaction (QEI) in the normal joint analyses for Q/H and Y/H population, respectively, and about 73% of the QTLs detected did not show significant QEI according to joint analyses for stress condition in Q/H. Most of the detected major QTLs exhibited high stability across different environments. Besides, several major QTLs were detected with large and consistent effect under normal condition (Chr. 6 and 7 in Q/H; Chr. 1, 3 and 9 in Y/H), or across 2 water regimes (Chr. 1, 8 and 10 for in Q/H). There were several constitutive QTLs (3 for Q/H and 1 for Y/H) with no or minor QTL-by-environment for the 2 populations. Finally, we found several genomic regions (Chr. 1, 10, etc.) to be co-located across the populations, which could provide useful reference for genetic improvement of these traits in maize breeding programs. Comparative genomic analysis revealed that 3 genes/genetic segments associated with plant height in rice were orthologous to these 3 identified genomic regions carrying the major QTLs for plant and ear height on Chr. 1, 6, and 8, respectively.

Detection of Consensus Genomic Region of QTLs Relevant to Drought-Tolerance in Maize by QTL Meta-Analysis and Bioinformatics Approach

Abstract Mapping consensus genomic regions for drought-tolerance is of great importance in molecular breeding of maize (Zea mays L.). This study aimed to integrate published quantitative trait loci (QTLs) relevant to drought tolerance under water stress that were identified in different experiments. Based on the high-density linkage map of IBM2 2008 Neighbors, a total of 79 Meta-QTLs (MQTLs) were screened out through the methods of “overview” and meta-analysis, of which 43 (54.4%) contained information of genes conferring drought tolerance according to bioinformatic analysis. By integrating the genetic map and the physical map of maize via Genome Brower in maize genome database ( http://www.maizegdb.org/ ), the physical map distance of MQTLs was estimated and the function of these candidate drought tolerance-related genomic regions was analyzed based on sequence information from the maize sequence database ( http://www.maizesequence.org/ ). The results showed that these regions contained abundant sequences of transcription factors such as MYB, bZIP and DREB, and a number of functional genes of LEA family.

Correlations and comparisons of quantitative trait loci with family per se and testcross performance for grain yield and related traits in maize.

Simultaneous improvement in grain yield and related traits in maize hybrids and their parents (inbred lines) requires a better knowledge of genotypic correlations between family per se performance (FP) and testcross performance (TP). Thus, to understand the genetic basis of yield-related traits in both inbred lines and their testcrosses, two F2:3 populations (including 230 and 235 families, respectively) were evaluated for both FP and TP of eight yield-related traits in three diverse environments. Genotypic correlations between FP and TP,

Identification of a QTL for Plant Height in a New Dwarf Germplasm of Maize

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QTL analysis for yield components and kernel-related traits in maize across multi-environments

(FP, TP), were low (0–0.16) for grain yield per plant (GYPP) and kernel number per plant (KNPP) in the two populations, but relatively higher (0.32–0.69) for the other six traits with additive effects as the primary gene action. Similar results were demonstrated by the genotypic correlations between observed and predicted TP values based on quantitative trait loci positions and effects for FP,

Increasing Maize Productivity in China by Planting Hybrids with Germplasm that Responds Favorably to Higher Planting Densities

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