Influenza dello stress idrico sulla fertilita' delle spighe di alcune varieta' di grano

Four cultivars of durum wheat (Creso, Latino, Appio, Iapigia) and one of soft wheat (Manital) were grown in Apulia (Italy) for two consecutive years, under dry and well irrigated field conditions, to investigate the water stress influence on the spike fertility, during the grain formation stage. Close to the flowering stage, a sample of 40 spikes, derived from the main culm, was deprived of the spikelets located in the middle zone of the spike with the purpose of modifying the ratio between source and sink for assimilates. The change in source/sink ratio for assimilates aimed to test whether the spike fertility reduction, of the dry treatment relatively to the well irrigated one, was the consequence of the water stress preventing pollination and/or fecundation, or rather inducing a scarce carbohydrate availability provoking an embryonal abortion. The results showed the scarce carbohydrate availability, during the grain formation, to be the main factor responsible for the reduced spike fertility, under the occurring water stress intensity and distribution of the experiment.