Teosinte, the progenitor of maize, is restricted to tropical environments in Mexico and Central America. The pre-Columbian spread of maize from its center of origin in tropical Southern Mexico to the higher latitudes of the Americas required postdomestication selection for adaptation to longer day lengths. Flowering time of teosinte and tropical maize is delayed under long day lengths, whereas ...

Daylength controls flowering in many plant species. Early in the twentieth century, Garner and Allard (1920) first described the phenomenon of plants that flower only when daylength is longer or shorter than a particular threshold, named long-day and shortday plants, respectively. Rice is a shortday plant; flowering (termed “heading” in rice and other cereals) is promoted by short daylength. Ho...

Daylength controls flowering in many plant species. Early in the twentieth century, Garner and Allard (1920) first described the phenomenon of plants that flower only when daylength is longer or shorter than a particular threshold, named long-day and shortday plants, respectively. Rice is a shortday plant; flowering (termed “heading” in rice and other cereals) is promoted by short daylength. Ho...

Daylength controls flowering in many plant species. Early in the twentieth century, Garner and Allard (1920) first described the phenomenon of plants that flower only when daylength is longer or shorter than a particular threshold, named long-day and shortday plants, respectively. Rice is a shortday plant; flowering (termed “heading” in rice and other cereals) is promoted by short daylength. Ho...

For 17 cultivars of winter wheat (Triticum aestivum L.) different vernalisation and photoperiod responses were detected. The effect of photoperiod sensitivity was not significantly changed by vernalisation; different vernalisation responses were probably due to the presence of multiple alleles at Vrn loci. The delay in heading depended on the vernalisation deficit exponentially: y = parameter (...

A major quantitative trait locus (QTL) controlling response to photoperiod, Hd1 , was identified by means of a mapbased cloning strategy. High-resolution mapping using 1505 segregants enabled us to define a genomic region of z 12 kb as a candidate for Hd1 . Further analysis revealed that the Hd1 QTL corresponds to a gene that is a homolog of CONSTANS in Arabidopsis. Sequencing analysis revealed...

The role of photoperiod sensitivity (PS) of flowering genes have become well recognized in rice, whereas little attention has been drawn to the non-PS component of these genes, especially to their influence on gene-by-gene interactions. Rice populations in which the photoperiod-sensitive allele at Hd1 has become insensitive to photoperiod but continued to affect heading date (HD) were used in t...

Rats were housed in either continuous lighting (LL), an extended photoperiod of 18 h light-6 h dark (LD 18:6) or a 12 h light-12 h dark (LD 12:12) lighting cycle. The effects of these various lighting regimens on the sensitivity of dorsal lateral geniculate neurones to iontophoresed noradrenaline and serotonin (5-HT) was examined. Exposure to either continuous lighting or to an extended photope...

A major quantitative trait locus (QTL) controlling response to photoperiod, Hd1, was identified by means of a map-based cloning strategy. High-resolution mapping using 1505 segregants enabled us to define a genomic region of approximately 12 kb as a candidate for Hd1. Further analysis revealed that the Hd1 QTL corresponds to a gene that is a homolog of CONSTANS in Arabidopsis. Sequencing analys...