Vernalization genes (Vrn), in addition to controlling the growth habit of wheat (spring and winter), play a key role in flowering time and early maturity of wheat. They are also of great interest in drought tolerance researches. To investigate the effect of Vrn genes on drought tolerance, four isogenic lines were developed. Isogenic lines were resulted from the crosses of the early heading Australian variety, Excalibur, with the late heading Iranian variety, Roshan, and followed by backcrossing with Roshan. Two experiments were conducted based on randomized complete block design with four replications under rainfed conditions of Sepidan during 2019-2020 and under well-watered conditions of Kerman during 2020-2021 cropping years. In the present research, seven important agronomic traits, including days to heading, days to ripening, grain filling period, spike number per meter square, grain number per spike, 1000-grain weight, and grain yield were assessed. Isogenic lines were assessed for drought tolerance using eight indices, including mean of productivity (MP), yield index (YI), stress tolerance index (STI ), geometric mean of productivity (GMP), stress susceptibility index (SSI ), yield stability index (YSI), and stress tolerance score (STS). The results of stress tolerance score (STS) showed that isogenic lines vrn-B1/Vrn-D1a and Vrn-B1a/vrn-D1 had the highest and the lowest stress tolerance score, respectively. In addition, the vrn-B1 and Vrn-D1a alleles, which cause early flowering, improve drought tolerance by utilizing an escape mechanism from dry conditions.

Considering the high production potential of quinoa plant, especially under stressful conditions such as drought and salinity, it is necessary to introduce new and high-yielding genotypes for cultivation in different regions of Iran. The objective of this research was to evaluate the diversity of 26 new and foreign quinoa genotypes in terms of morphophenological characteristics. The experiment was carried out in a completely randomized design with three replications in greenhouse of Rice Research Institute of Iran (RRII), Rasht, in 2021. The results of analysis of variance showed that there was a very significant statistical difference among the studied genotypes for all measured traits. Factor analysis using the principal components method identified three main and independent factors that explained 39.19, 24.63, and 15.94%, respectively, and in total about 80% of the total variance. In addition, cluster analysis based on Ward's minimum variance grouped the studied 26 quinoa genotypes into three separate clusters; including 14, 7, and 5 genotypes, which very largely corresponded to grouping of the principal components. In total, the results of the current study showed that among the studied 26 quinoa genotypes, genotype No. 12 with 1000-grain weight, panicle length, and grain yield higher than the other genotypes as well as dwarfism and earliness characteristics was the most valuable genotype of this experiment. Furthermore, genotypes No. 4, 8, 17, and 18 for grain yield, genotypes No. 7, 13, and 15 for earliness, and genotype No. 14 for dwarfism, were the promising genotypes of this research, which can be used to transfer earliness and dwarfism to high-yielding genotypes in future breeding programs.