Allelic variation at the PPD-A1 locus and its associations with heading time and winter wheat (Triticum aestivum L.) agronomic traits in the northern Black Sea region

Abstract

Aim. The identification of Ppd-1-alleles in winter bread wheat varieties of various origin, including the ones of Ukrainian plant breeding and recombinant-inbred lines Orenburgskaya 48//Cappelle Desprez/2В Chinese Spring, and the evaluation of the effects of allele Ppd-А1_del303, including the interaction with different alleles of gene Ppd-B1, by the duration of the period before heading and the related agronomically valuable traits. Methods. DNA extraction, allele-specific PCR, agarose and polyacrylamide gel electrophoresis, phenological observations, evaluation of frost resistance in seedlings, and analysis of morphobiological traits and elements of yield structure. Statistical analysis of the obtained data was carried out in Microsoft Excel. The significance of the difference between samples was assessed by Fisher's F test. A difference of p < 0.05 was considered statistically significant for all indicators. Results. The marking of 30 varieties of different origin and 64 recombinant-inbred lines of Orenburgskaya 48//Cappelle Desprez/2B Chinese Spring winter bread wheat was carried out to identify the alleles of the Ppd-A1 gene. The polymorphism of varieties and populations of recombinant-inbred lines in the northern Black Sea region (Odesa) was evaluated for ten traits: frost resistance of plants in the seedling phase, winter hardiness, duration of the period before heading, plant height, grain number per spike, grain weight per spike, thousand grain weight, number of productive tillers per unit area, harvest index and grain yield. The comparison of the lines evaluation data in terms of agronomic traits and the results of the genotypes identification allowed us to identify the influence of Ppd-A1 gene alleles and various combinations of the alleles of Ppd-A1 and Ppd-B1 genes on these traits. Conclusions. A higher prevalence of the Ppd-A1_del303 allele was found both among varieties and recombinant-inbred lines. The genetic differences by the Ppd-A1 gene (Ppd-A1_del303 or Ppd-A1b) are significantly related only to frost resistance of seedlings in the absence of significant differences in other traits. The interaction between Ppd-A1b and Ppd-B1c alleles contributed to the acceleration of early maturity and the formation of the highest indicators of grain weight per spike, thousand grain weight, harvest index, and grain yield. The replacement of the Ppd-A1b allele with Ppd-A1_del303 led to a decrease in the effect of the dominant Ppd-B1c allele on accelerating heading and negatively affected the grain weight per spike, thousand grain weight, harvest index and grain yield compared to the Ppd-A1b Ppd-B1c genotype.