Department of Crop and Forest Sciences and AGROTECNIO (Center for Research in Agrotechnology), University of Lleida, Lleida, Spain.
John Innes Centre, Norwich Research Park, Colney Lane, Norwich, UK.
J Exp Bot. 2018 Apr 27;69(10):2633-2645. doi: 10.1093/jxb/ery105.
As wheat yield is linearly related to grain number, understanding the physiological determinants of the number of fertile florets based on floret development dynamics due to the role of the particular genes is relevant. The effects of photoperiod genes on dynamics of floret development are largely ignored. Field experiments were carried out to (i) characterize the dynamics of floret primordia initiation and degeneration and (ii) to determine which are the most critical traits of such dynamics in establishing genotypic differences in the number of fertile florets at anthesis in near isogenic lines (NILs) carrying photoperiod-insensitive alleles. Results varied in magnitude between the two growing seasons, but in general introgression of Ppd-1a alleles reduced the number of fertile florets. The actual effect was affected not only by the genome and the doses but also by the source of the alleles. Differences in the number of fertile florets were mainly explained by differences in the floret generation/degeneration dynamics, and in most cases associated with floret survival. Manipulating photoperiod insensitivity, unquestionably useful for changing flowering time, may reduce spike fertility but much less than proportionally to the change in duration of development, as the insensitivity alleles did increase the rate of floret development.
由于特定基因的作用，小麦产量与粒数呈线性关系，因此了解基于小花发育动态的可育小花数的生理决定因素是很重要的。光周期基因对小花发育动态的影响在很大程度上被忽视了。进行了田间试验，（i）描述小花原基起始和退化的动态，（ii）确定在携带光周期不敏感等位基因的近等基因系（NILs）中，哪些是决定小花数量动态的最关键特征，从而在开花期建立可育小花数的基因型差异。结果在两个生长季节之间有很大的差异，但一般来说，Ppd-1a 等位基因的导入减少了可育小花的数量。实际效果不仅受到基因组和剂量的影响，还受到等位基因来源的影响。小花数量的差异主要由小花世代/退化动态的差异来解释，而且在大多数情况下与小花的存活率有关。改变光周期不敏感，无疑有助于改变开花时间，但对穗部结实率的影响远小于发育持续时间的变化比例，因为不敏感等位基因确实提高了小花发育的速度。
