Shiraz University Iran Agricultural Research 1013-9885 44 1 2025 04 01 The impacts of earlier flowering on grain yield of winter wheat cultivars under semi-arid conditions 89 102 8088 10.22099/iar.2025.52009.1661 EN Maryam Jahani Doghozlou Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, I. R. Iran Yahya Emam Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, I. R. Iran Afshin Zamani Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, I. R. Iran Journal Article 2024 12 28 The timing of wheat anthesis, often coinciding with late-season drought stress, can significantly reduce grain number and yield. Field and greenhouse experiments conducted at Shiraz University, Shiraz, Iran, during the 2019–2021 growing seasons investigated how early flowering may mitigate yield reduction. The study aimed to assess the impact of phenological timing on yield components and overall yield performance. Ten widely adopted cultivars, introduced over the past five decades, were used. The high-yielding cultivars (Baharan, Sirvan, and Chamran) exhibited significantly more grains per spike and a greater biological yield. This increased phytomass production was accompanied by a higher harvest index. Stem elongation began earlier in the superior cultivars, while cultivars with extended flowering periods (Navid, Bayat, and Shiraz) had the lowest grain yield. Floret development monitoring revealed that floret degradation occurred earlier and lasted longer in low-yielding cultivars, beginning from the yellow anther stage. In contrast, high-yielding cultivars experienced a shorter floret abortion period, from heading to anthesis. In semi-arid regions, early flowering and reduced floret abortion periods may enhance grain yield. Unlocking the full potential of superior cultivars requires a deeper understanding of the genetic mechanisms driving early flowering in these varieties. https://iar.shirazu.ac.ir/article_8088_2c7489e33dbf2d4ff1ce367d406993c6.pdf