Effects of Ppd alleles on heading and flowering time of wheat in climatic conditions of South-Eastern Europe

Photoperiod response (Ppd) genes play a key role in fine-tuning of heading and flowering time and adaptation of wheat to different agro -climatic conditions, which could increase crop yield. The aim of this study was to analyse genotypes carrying different Ppd-1 alleles and their influence on wheat phenology in growing conditions of the South-Eastern Europe. The experiment was conducted with 10 well-adapted Serbian wheat varieties and 54 NILs of cv. Paragon with single, double and triple doses of Ppd-1 alleles. The genotypes were sown in the plot size of 2 m 2 at the location of Rimski Sancevi (45°20`N, 19°51`E), in randomized complete block design with 3 replications. Heading and flowering time were recorded during three growing seasons (2014, 2015 and 2017). The results showed that the genotype, growing season and their interactions had significant effects on both analysed traits. The Serbian varieties (set 1) were significantly earlier regarding the heading and flowering time than cv. Paragon, and most of the NILs. The NILs with introgressed single (set 2) insensitivity Ppd-1 alleles were earlier than the original cv. Paragon in 2014 and 2015, but not in 2017. When the same alleles were introgressed in a double dose (set 3), they significantly reduced heading and flowering time in all seasons. The NILs with introgressed Ppd-1 null alleles and knock-outs (set 4) were significantly later than cv. Paragon, and all other sets of genotypes. All indicated changes caused by different Ppd-1 alleles were variable expressed in different growing seasons