EFFECTS OF MUTANT ALLELES OF THE PPD-1 GENE ON THE DATE TO HEADING UNDER NATURAL AND SHORTENED DAYLENGTH CONDITIONS

Abstract

The purpose of this work was to identify recombinant inbred lines from the hybrid of Orenburgskaya 48 //Cappelle Desprez/2B Chinese Spring and to evaluate the effects of recessive alleles of the Ppd-D1 and Ppd-A1 genes, as well as their interaction with the dominant allele of the Ppd-B1c gene, on heading dates under environment of natural and shortened photoperiods. The study was conducted on a population of 64 recombinant inbred lines and two parental genotypes. Five-days-old seedlings of each genotype were subjected to vernalization for 50 days and grown on the vegetation site under natural and artificially shortened to 10 hours photoperiods. During the growing season, the dates to heading (DH) of individual plants were recorded when the main spike appeared from the sheath of the flag leaf. Known allele-specific molecular markers were used for identifying carriers of Ppd-D1c, Ppd-D1d, Ppd-A1b and Ppd-A1b-del303 alleles. It was shown that mutant recessive alleles of Ppd-A1 and Ppd-D1 genes do not affect significantly the DH in winter bread wheat plants under environment of natural and reduced photoperiods. The dominant Ppd-B1c allele, regardless of the presence of certain recessive alleles of the Ppd-D1 and Ppd-A1 genes, contributes to the acceleration of the development (acceleration of DH) of plants at different day lengths compared to such carriers of the Ppd-B1b allele. The presence of the mutant recessive allele Ppd-A1b_del303 in the genotype of the line leads to a decrease in the effect of the dominant allele of the Ppd-B1c allele on the acceleration of heading. The interaction of the dominant allele Ppd-B1c in shortening the DH with the genes Ppd-A1b and Ppd-D1d revealed more effective on the reduced photoperiod, аnd with Ppd-A1b and Ppd-D1c on the natural day, and it was the least effective in both variants of the experiment for the combination of alleles Ppd-A1b Ppd -B1b Ppd-D1d. Allelic differences of the three Ppd-1 genes determined 54.2% of the diversity of RIL in terms of the DH under natural environment and 59.9% - at shortened days, it was to a greater extent observed due to allelic differences of the Ppd-B1 gene.