Influence of time of sowing, photoperiod, and temperature on supernumerary spikelet expression in wheat (Triticum)

Abstract

Three tetraploid (Triticum turgidum L. emend, gr. turgidum and gr. durum) and six hexaploid wheats (Triticum × aestivum L. emend aestivum) with reported tendencies for "branched" heads (supernumerary spikelets) exhibited variation for this character when grown under different photoperiod and temperature regimes. Wheats with a weak vernalization response under short photoperiod in an outdoor (low temperature) environment and those with a strong vernalization response under a long-photoperiod outdoor (low temperature) environment developed more supernumerary spikelets than under other photoperiods and temperatures. There was a variation among the nine wheats in the level and stability of supernumerary spikelet expression and in their fertility and grain number per head over the different times of sowing. This indicates the feasibility for selecting high and stable expression of supernumerary spikelets in breeding to increase spikelet number per head in wheat.