Jansen Constantin, Zhang Yongzhong, Liu Hongjun, Gonzalez-Portilla Pedro J, Lauter Nick, Kumar Bharath, Trucillo-Silva Ignacio, Martin Juan Pablo San, Lee Michael, Simcox Kevin, Schussler Jeff, Dhugga Kanwarpal, Lübberstedt Thomas
Department of Agronomy, Iowa State University, Ames, IA, 50011, USA.
Theor Appl Genet. 2015 Jul;128(7):1231-42. doi: 10.1007/s00122-015-2486-0. Epub 2015 Mar 12.
Exploring and understanding the genetic basis of cob biomass in relation to grain yield under varying nitrogen management regimes will help breeders to develop dual-purpose maize. With rising energy demands and costs for fossil fuels, alternative energy from renewable sources such as maize cobs will become competitive. Maize cobs have beneficial characteristics for utilization as feedstock including compact tissue, high cellulose content, and low ash and nitrogen content. Nitrogen is quantitatively the most important nutrient for plant growth. However, the influence of nitrogen fertilization on maize cob production is unclear. In this study, quantitative trait loci (QTL) have been analyzed for cob morphological traits such as cob weight, volume, length, diameter and cob tissue density, and grain yield under normal and low nitrogen regimes. 213 doubled-haploid lines of the intermated B73 × Mo17 (IBM) Syn10 population have been resequenced for 8575 bins, based on SNP markers. A total of 138 QTL were found for six traits across six trials using composite interval mapping with ten cofactors and empirical comparison-wise thresholds (P = 0.001). Despite moderate to high repeatabilities across trials, few QTL were consistent across trials and overall levels of explained phenotypic variance were lower than expected some of the cob trait × trial combinations (R (2) = 7.3-43.1 %). Variation for cob traits was less affected by nitrogen conditions than by grain yield. Thus, the economics of cob usage under low nitrogen regimes is promising.
探索和理解在不同氮素管理模式下玉米穗轴生物量与籽粒产量相关的遗传基础，将有助于育种者培育出两用型玉米。随着能源需求的增加和化石燃料成本的上升，来自可再生资源（如玉米穗轴）的替代能源将变得具有竞争力。玉米穗轴作为原料具有有益的特性，包括组织紧密、纤维素含量高、灰分和氮含量低。氮素是植物生长中数量上最重要的养分。然而，氮肥对玉米穗轴产量的影响尚不清楚。在本研究中，对正常和低氮条件下玉米穗轴的形态性状（如穗轴重量、体积、长度、直径和穗轴组织密度）以及籽粒产量进行了数量性状位点（QTL）分析。基于单核苷酸多态性（SNP）标记，对B73×Mo17（IBM）Syn10群体的213个双单倍体株系在8575个位点进行了重测序。使用包含10个辅助因子的复合区间作图法和经验性比较阈值（P = 0.001），在六个试验中对六个性状共检测到138个QTL。尽管不同试验间具有中度到高度的重复性，但跨试验一致的QTL较少，部分穗轴性状×试验组合的表型变异解释率总体水平低于预期（R² = 7.3 - 43.1%）。穗轴性状的变异受氮素条件的影响小于籽粒产量。因此，低氮条件下玉米穗轴利用的经济性很有前景。
