Genetic dissection of plant architecture and yield-related traits in Brassica napus.

Chunyu Zhang,Chuchuan Fan,Yongming Zhou,Qian Yang,Guangqin Cai,Hao Chen,Qingyong Yang

doi:10.1038/srep21625

Abstract

An optimized plant architecture (PA) is fundamental for high-yield breeding but the genetic control of the important trait is largely unknown in rapeseed. Here plant architecture factors (PAFs) were proposed to consist of main inflorescence length proportion (MILP), branch height proportion (BHP), and branch segment proportion (BSP). Comparison of different genotypes in a DH population grown in diverse environments showed that an optimized PAF performance with MILP and BHP between 0.3–0.4 was important for high yield potential. In total, 163 unique quantitative trait loci (QTLs) for PA- and plant yield (PY)-related traits were mapped onto a high-density genetic map. Furthermore, 190 PA-related candidate genes for 91 unique PA QTLs and 2350 PY epistatic interaction loci-pairs were identified, which explain 2.8–51.8% and 5.2–23.6% of phenotypic variation, respectively. Three gene categories, transcription factor, auxin/IAA, and gibberellin, comprise the largest proportions of candidate genes for PA-related QTLs. The effectiveness of QTL candidate genes prediction was demonstrated by cloning of three candidate genes, Bna.A02.CLV2, Bna.A09.SLY2, and Bna.C07.AHK4. The study thus outlines a gene network for control of PA-related traits and provides novel information for understanding the establishment of ideal PA and for developing effective breeding strategies for yield improvement in rapeseed and other crops.

Highlights

Many of these genes are involved in hormone biosynthesis and regulation
To quantify variations in Plant architecture (PA)-traits, we divided a plant into three segments (Fig. 1): main inflorescence length (MIL), branch height (BH), and branch segment (BS)
These three segment measurements were divided by plant height (PH) so as to obtain three proportion values: MIL proportion (MILP), BH proportion (BHP) and BS proportion (BSP)

Summary

Introduction

Many of these genes are involved in hormone biosynthesis and regulation. Genes controlling plant height are related to gibberellin (GA) metabolism and signal transduction[4,11]. Quantitative trait loci (QTLs) and candidate genes involved in the genetic control of PA and their interactions with plant yield (PY) were identified. To evaluate the effects of PAFs on PY and PY-related traits, the DH lines with significant differences in PY were grouped into two pools (i.e., high-yield and low-yield pools) in each environment (Table 1).

Results

Conclusion