توصيفگر ها :
پروفايل SRC , ژن NAM-B1 , سطوح پلوئيدي گندم , غني¬سازي زيستي , گندم¬هاي پوشينه¬دار , محلول¬پاشي برگي , محتواي پروتئين دانه , محتواي روي و آهن دانه
چكيده انگليسي :
Cultivated emmer wheat (T. turgidum ssp. dicoccum, 2n=4x=28) is generally belived to serve as the ancestor of modern wheat. Notably, it holds significant promise for improving durum wheat, particularly in terms of elevating grain protein content (GPC). The experiment was conducted as a split plot using a randomized complete block design with three replications. In this setting, the main factor was four levels of urea fertilizer (0, 50, 150, and 200 kg ha-1), and the 12 wheat genotypes were considered the sub-factors. The results of the analysis of variance showed that the effect of nitrogen fertilizer levels on days to physiological maturity, GPC percentage, nitrogen percentage, and nitrogen concentration in grains was significant (p<0.01). Emmer genotypes had higher means for spike number per square meter, GPC, nitrogen concentration in grain, and protein percentage than durum wheat genotypes. Also, to examine the possibility of concurrent improvement of the two species, the eight durum cultivars were crossed with the four emm Then, based on more GY, 84 higher-yielding genotypes from all three ploidy levels with different geographical origins were selected for grain zinc (Zn) and iron (Fe) measurements. In all three ploidy levels, hulled wheat showed higher Zn, Fe, and GPC and lower GY than modern cultivars. Then another experiment was conducted to investigate the reaction of selected species (from the 2018-2019 study) with different ploidy levels to foliar spraying of Zn and Fe under water stress conditions. The 35 selected wheat genotypes, including nineteen tetraploids from ten different species, ten hexaploids from five species, and six diploids from three species, were evaluated in the field (2019-2020) over two moisture regimes with the following four treatments: control, foliar Zn application, foliar Fe application, and foliar Zn+Fe application. The experiment used a split-plot scheme in a randomized complete block design with two replications in each moisture regime. Water stress negatively affected all measured traits, including GY and TKW. Foliar application of Zn and Zn+Fe significantly increased GY and TKW and alleviated their reduction caused by water stress. While the grain quality traits, including solvent retention capacity (SRC) values, GPC, Zn, and Fe content, increased. Zinc application increased SRC profiles for 4x and 6x genotypes. Remarkably, the Zn application alleviated yield reduction caused by water stress. Moreover, the Zn application increased grains' Zn, potassium content (K+), the ratio of potassium to sodium content (K+/Na+), RWC, Chl, Car contents, Pox, Aes, and Cat activities while significantly reducing MDA, HP, and Na+ contents compared with the control treatment. The results of this experiment indicated the effectiveness of Zn foliar spraying in improving agronomical and quality traits and reducing the effects of water stress. Finally, a study aimed at the association of the NAM-B1 gene with increased amounts of GPC, Zn, and Fe grain content. For this reason, 38 wheat accessions comprising ten hexaploids from five species and 28 tetraploids from nine species were evaluated in the field for two consecutive years (2018-2020), and the 582 first nucleotides of this gene were sequenced. The NAM-B1 gene was present in 21 tetraploids and five hexaploid accessions. These findings further support the possibility of simultaneously improving wheat GPC, Zn, and Fe content by a single gene crucial for human nutrition and health worldwide.
