جستجوی مقالات مرتبط با کلیدواژه "photoperiod genes (ppd)" در نشریات گروه "بیوتکنولوژی و ژنتیک گیاهی"

Early heading as an adaptation mechanism for end season heat and drought stress is an important goal in wheat breeding programs. Photoperiod (Ppd) and vernalization (Vrn) are the most important genes controlling early heading in bread wheat. The aim of the present study was to investigate the effect of Ppd and Vrn genes on early heading, grain yield and important agronomic traits in BC4F2 generation of Roshan (recurrent parent) and Excalibur backcross.

A BC4F2 population resulted from backcross of Roshan and Excalibur was generated in Shahid Bahonar University of Kerman. In this breeding program, early heading was transferred from Excalibur cultivar to Roshan (recurrent parent). This population, including 175 BC4F2 progenies, and their parents were cultivated in the research field of Shahid Bahonar University of Kerman in the 2019-2020 growing season. The progenies were genotyping using specific markers Vrn-B1, Vrn-D1 and Ppd-D1. In this population, early heading, grain yield and important agronomic traits were evaluated.

Excalibur and Roshan had Ppd-D1a, and Ppd-D1b alleles, respectively. The frequency of Ppd-D1a/Ppd-D1a and heterozygous genotypes in the evaluated population were 27.33% and 415%, respectively. In this population, Ppd-D1a/Ppd-D1a, which is photoperiod insensitive genotype, was 6 and 4 days earlier heading than Ppd-D1b/Ppd-D1b and Ppd-D1a/Ppd-D1b genotypes, respectively. There was no allelic diversity between progeny for Vrn-1 locus. Early heading had a significant negative correlation with grain yield, 1000-grain weight, spikes number and grains number per spike.

The results confirm the importance of Ppd-D1a gene in the early heading, grain yield and yield components. Selection for early heading increased grain yield, 1000-grain weight, spikes number, biological yield, stover biomass at harvest and spikes dry weight. Due to the large and significant effect of Ppd-D1a gene on grain yield and yield components, we recommend marker assisted selection of this gene in wheat breeding programs. Phenotypic selection was performed before BC4F2 generation and Vrn gene diversity was established in the population.

 Photoperiod controlling genes (Ppd) are the most important genes groups that modify early heading in bread wheat. The aim of this research was to evaluate Ppd genes in Iranian cultivars, and also assessing the effect of Ppd-D1a on earliness trait.

Material and methods

 Earliness was transferred from Excalibur to Kalhaydari, Roshan and Mahdavi cultivars using backcross method to generate BC1F3 generation. Three photoperiod controlling genes including Ppd-A1, Ppd-B1 and Ppd-D1 were assessed in Iranian cultivars using PCR by specific primers. Bulk segregation analysis of Ppd-D1 loci was done for early heading genotypes in three populations. Two years field evaluation were conducted to show the effect of selection for earliness on important agronomic traits of bread wheat.

 Mahdavi, Ghods, Kalhaydari, Sardari, Roshan, Kavir, Excalibur and Shahpasand were containing Ppd-A1b and Ppd-B1b. Kalhaydari, Sardari, Roshan and Kavir were containing Ppd-D1b, while Mahdavi, Ghods, Excalibur and Shahpasand were possessed Ppd-D1a. Bulk segregation analysis of 10% of the earliest heading BC1F3 populations showed that early heading progenies were possessing Ppd-D1a. Positive significant correlation was observed between early heading and earliness. Meanwhile, days to heading had a negative correlation with grain filling period. Longer grain filling period improved 1000-grain weight, grain number per plant and grain yield. Selection for early heading improved plant height, leaf size, spike number per plant, seed number per plant, 1000-grain weight and grain yield, while decreased spike length, awn length and infertile tiller number.

 Marker assisted selection or marker assisted backcross of Ppd-D1a gene could improve earliness in bread wheat. Early heading was improved in Roshan, Kalhaydari and Mahdavi background for 13, 14 and 1o days, respectively. Selection for early heading improved the most important grain yield related agronomic traits in Kerman condition.