Transgenerational Paternal Inheritance of GFMs Expression Patterns Indicate a Way to Select Wheat Lines with Better Parameters for Yield-Related Traits.

Members of the gene family (GFMs) encode the cytokinin oxygenase/dehydrogenase enzyme (CKX), which irreversibly degrades cytokinins in the organs of wheat plants; therefore, these genes perform a key role in the regulation of yield-related traits. The purpose of the investigation was to determine how expression patterns of these genes, together with the transcription factor-encoding gene , and yield-related traits are inherited to apply this knowledge to speed up breeding processes. The traits were tested in 7 days after pollination (DAP) spikes and seedling roots of maternal and paternal parents and their F progeny. The expression levels of most of them and the yield were inherited in F from the paternal parent. Some pairs or groups of genes cooperated, and some showed opposite functions. Models of up- or down-regulation of GFMs and in low-yielding maternal plants crossed with higher-yielding paternal plants and their high-yielding F progeny reproduced gene expression and yield of the paternal parent. The correlation coefficients between GFMs, , and yield-related traits in high-yielding F progeny indicated which of these genes were specifically correlated with individual yield-related traits. The most common was expressed in 7 DAP spikes , which positively correlated with grain number, grain yield, spike number, and spike length, and seedling root mass. The expression levels of or in the seedling roots were negatively correlated with these traits. In contrast, the thousand grain weight (TGW) was negatively regulated by , , and in 7 DAP spikes but positively correlated with and in seedling roots. Transmission of GFMs and expression patterns and yield-related traits from parents to the F generation indicate their paternal imprinting. These newly shown data of nonmendelian epigenetic inheritance shed new light on crossing strategies to obtain a high-yielding F generation.