Meyer Rhonda C, Törjék Ottó, Becher Martina, Altmann Thomas
Max-Planck-Institute of Molecular Plant Physiology, Golm, Germany.
Plant Physiol. 2004 Apr;134(4):1813-23. doi: 10.1104/pp.103.033001. Epub 2004 Apr 2.
Heterosis has been widely used in agriculture to increase yield and to broaden adaptability of hybrid varieties and is applied to an increasing number of crop species. We performed a systematic survey of the extent and degree of heterosis for dry biomass in 63 Arabidopsis accessions crossed to three reference lines (Col-0, C24, and Nd). We detected a high heritability (69%) for biomass production in Arabidopsis. Among the 169 crosses analyzed, 29 exhibited significant mid-parent-heterosis for shoot biomass. Furthermore, we analyzed two divergent accessions, C24 and Col-0, the F(1) hybrids of which were shown to exhibit hybrid vigor, in more detail. In the combination Col-0/C24, heterosis for biomass was enhanced at higher light intensities; we found 51% to 66% mid-parent-heterosis at low and intermediate light intensities (60 and 120 micromol m(-2) s(-1)), and 161% at high light intensity (240 micromol m(-2) s(-1)). While at the low and intermediate light intensities relative growth rates of the hybrids were higher only in the early developmental phase (0-15 d after sowing [DAS]), at high light intensity the hybrids showed increased relative growth rates over the entire vegetative phase (until 25 DAS). An important finding was the early onset of heterosis for biomass; in the cross Col-0/C24, differences between parental and hybrid lines in leaf size and dry shoot mass could be detected as early as 10 DAS. The widespread occurrence of heterosis in the model plant Arabidopsis opens the possibility to investigate the genetic basis of this phenomenon using the tools of genetical genomics.
杂种优势已在农业中广泛用于提高产量和拓宽杂交品种的适应性，并且应用于越来越多的作物品种。我们对63个拟南芥生态型与三个参照系（Col-0、C24和Nd）杂交后的干生物量杂种优势的程度进行了系统调查。我们检测到拟南芥生物量生产具有较高的遗传力（69%）。在分析的169个杂交组合中，29个表现出显著的地上部生物量中亲杂种优势。此外，我们更详细地分析了两个差异较大的生态型C24和Col-0，其F(1)杂种表现出杂种活力。在Col-0/C24组合中，较高光照强度下生物量的杂种优势增强；我们发现在低光和中等光照强度（60和120 μmol m(-2) s(-1)）下中亲杂种优势为51%至66%，在高光强度（240 μmol m(-2) s(-1)）下为161%。虽然在低光和中等光照强度下，杂种的相对生长速率仅在发育早期阶段（播种后0 - 15天[DAS]）较高，但在高光强度下，杂种在整个营养生长阶段（直至25 DAS）都表现出相对生长速率增加。一个重要发现是生物量杂种优势的早期出现；在Col-0/C24杂交组合中，早在10 DAS时就能检测到亲本系和杂种系在叶片大小和地上部干质量方面的差异。模式植物拟南芥中杂种优势的广泛存在为利用遗传基因组学工具研究这一现象的遗传基础提供了可能性。
