Genotypical and phenotypical characterization of old and modern bread wheat cultivars for agronomical and quality traits

This study was conducted to determine the genotypic differences among 189 registered bread wheat (Triticum aestivum L.) varieties, and 34 hulled wheat lines improved by selection breeding by using 22 molecular markers for adaptive and quality traits. In addition, the field experiments were carried out with 22 genotypes consisted of ancient, old and modern bread wheat varieties/candidates by randomized complete block design with three replicates in irrigated conditions in Ilgın/Konya during 2018-2019 and 2019-2020 growing seasons. In genotypic characterization conducted for adaptive traits such as vernalization and photoperiodic response, it was determined that the frequencies of alleles vrn-A1, vrn-B1, vrn-D1 and Ppd-D1a have been clearly increased from past to present. It was also determined that the frequency of the allele Rht-B1b has been considerably increased after the Green Revolution. On the other hand, the allele Rht-D1b was found only in 8 varieties. The frequency of the allele Rht-24b pronounced as the new Green Revolution gene in recent years was determined to be 50.2% among the genotypes studied. In genotypic characterization of the genes affecting grain quality, the allele NAM-B1a leading to high grain protein content was not identified in any of the genotypes. However, the most frequent allele combinations for puroindolines (Pin) were Pina-D1a/Pinb-D1a and Pina-D1a/Pinb-D1b (64.9% and 28.8%, respectively), followed by Pina-D1b/Pinb-D1a and Pina-D1a/Pinb-D1c (5.8% and 0.5%, respectively). It was also determined that the most frequent allele combinations for high molecular weight glutenin subunits (HMWG) were Ax2* (44.0%), Bx7 + By8 (42.3%) and Dx5 + Dy10 (64.9%), respectively. In addition, 48 bread wheat varieties had 10 points with high gluten quality according to quality scoring for high molecular weight glutenin subunit (HMWG) combinations. In the second part of the study, statistically important differences were found among the genotypes for all agronomical and quality traits based on two years data. In addition, cultivar × year interaction was also important for all traits except for spike length and number of spikes per square. Taking into consideration the obtained data for old and modern wheat cultivars/candidates, it was determined that while grain yield, harvest index, volume weight, sedimantation volume and gluten index have been increased from past to present, plant height and number of spikes per square have decreased. According to linear regression analysis, the genetic gain in plant height, number of spikes per square, grain yield, harvest index, volume weight, grain hardness, sedimantation volume and gluten index were calculated as -0.22 cm, -23.47, 18.5 kg/ha, 0.10%, 0.06 kg/l, 0.09 PSI%, 0.22 ml and 0.22%, respectively. Additionally, no differences was found in protein content and wet gluten ratio between old and modern varieties. In this study, it was revealed that the bread wheat varieties cultivated in Turkey changed genotypically and phenotypically to some extent from 1931 to present with breeding activities. Considering the effects of climate change especially on agriculture in the world and Turkey in recent years, it is expected that these findings will be beneficial to the bread wheat breeding studies carried out in the country.