The present invention relates to a seed comprising in its genome a modified NXS gene and/or modified regulatory sequences thereof. The modified NXS gene and/or modified regulatory sequences thereof provides the seed with the capability to germinate at a high temperature as compared to a wild type seed not having the modified NXS gene. The modification to the gene and/or its regulatory sequences may lead to the expression of the NXS gene being substantially reduced or prevented. In addition to or alternatively, the seed can have a reduced level, reduced activity or complete absence of NXS protein. The modified NXS gene may for example comprise a premature stop codon and/or encode an NXS protein that comprises one or more amino acid substitutions.