Coupling anthesis date to the most suitable environmental conditions is critical for wheat (Triticum aestivum L.) adaptation and yield potential. Development to anthesis is controlled by temperature and photoperiod. Response to photoperiod is chiefly modulated by Ppd-1 genes, but their effect on the quantitative response to photoperiod of (i) time to anthesis and (ii) pre-anthesis phases remains largely unknown. A photoperiod-sensitive spring cultivar, Paragon, and near-isogenic lines of it carrying different combinations of Ppd-1a insensitivity alleles were tested under a wide range of photoperiods, including switches in photoperiod at the onset of stem elongation. Using multimodel inference we found that Ppd-1a alleles reduced photoperiod sensitivity of (i) emergence to anthesis and (ii) emergence to onset of stem elongation, both in a less than additive manner, while threshold photoperiod and intrinsic earliness were unaffected. Sensitivity to current photoperiod from onset of stem elongation to flag leaf and from then to anthesis was milder than for previous phases and was not related to variability in Ppd-1. However, 'memory' effects of previously experienced photoperiod on the duration from onset of stem elongation to flag leaf were related to variability in Ppd-1. The characterization and quantification provided here of the effects on development of Ppd-1 allelic combinations should help increase accuracy of genotype-to-phenotype models in predicting wheat phenology.

中文翻译：

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光周期敏感性基因（Ppd-1）：量化它们对小麦光周期反应模型的影响。

将花期与最合适的环境条件耦合对于小麦（Triticum aestivum L.）的适应和增产潜力至关重要。花粉的发育受温度和光周期的控制。对光周期的响应主要受Ppd-1基因调节，但是它们对（i）花期时间和（ii）花前期的光周期定量响应的影响仍然未知。在宽范围的光周期下测试了光周期敏感的春季品种Paragon及其携带Ppd-1a不敏感性等位基因不同组合的近等基因系，包括在茎伸长开始时光周期的转换。通过多模型推断，我们发现Ppd-1a等位基因降低了（i）对花粉的出芽和（ii）对茎伸长的发作的光周期敏感性，两者均以相加方式较少，而阈值的光周期和内在的早期不受影响。从茎伸长开始到旗叶以及从那时到花期对当前光周期的敏感性比以前的时期要温和，并且与Ppd-1的变异性无关。然而，先前经历的光周期对从茎伸长开始到旗叶持续时间的“记忆”效应与Ppd-1的变异性有关。此处提供的对Ppd-1等位基因组合发展的影响的表征和定量分析应有助于提高基因型-表型模型在预测小麦物候方面的准确性。从茎伸长开始到旗叶以及从那时到花期对当前光周期的敏感性比以前的时期要温和，并且与Ppd-1的变异性无关。然而，先前经历的光周期对从茎伸长开始到旗叶持续时间的“记忆”效应与Ppd-1的变异性有关。此处提供的对Ppd-1等位基因组合发展的影响的表征和定量分析应有助于提高基因型-表型模型在预测小麦物候方面的准确性。从茎伸长开始到旗叶以及从那时到花期对当前光周期的敏感性比以前的时期要温和，并且与Ppd-1的变异性无关。然而，先前经历的光周期对从茎伸长开始到旗叶持续时间的“记忆”效应与Ppd-1的变异性有关。此处提供的对Ppd-1等位基因组合发展的影响的表征和定量分析应有助于提高基因型-表型模型在预测小麦物候方面的准确性。