ASSESSING THE PHOTOSYNTHETIC CAPACITY AND STAY-GREEN TRAIT OF BREAD WHEAT (Triticum aestivum L.) CULTIVARS AND LINES UNDER FIELD CONDITIONS

This study evaluated the chlorophyll dynamics and photosynthetic potential of 20 bread wheat cultivars and lines during the stem elongation and grain filling periods. Results showed a significant increase in chlorophyll content from an average of 42.5 SPAD in the stem elongation stage to 51.6 SPAD during grain filling. Among the evaluated genotypes (ranging from 39.8 to 54.4 SPAD), cultivars such as Qorasuv, Zarbuloq, Gurt, and lines GA №55/2024, KP-183/2017, AE №7/2020, and D-83/2024 demonstrated significantly higher photosynthetic activity compared to the standard cultivar Zamin-1 (48.0 SPAD). By maintaining stable chlorophyll synthesis under heat and moisture deficit, these superior genotypes guarantee stable grain yield and high quality, serving as valuable donors for future breeding programs.