Volume 13, Issue 1 (Number 1 - 2011)
Abstract
Maize improvement for high temperature tolerance requires the reliable assessment of parental inbred lines and their combinations. Fifteen maize inbred lines were evaluated during 2007 and 2008 in Shushtar city (Khuzestan Province). The inbred lines were planted at two dates: 6 July, to coincide heat stress with pollination time; and 27 July, as normal planting to avoid high temperature during pollination and grain filling period. In addition, 28 hybrids from a combination of eight selected lines, were evaluated under the same conditions in 2008. Five stress tolerance indices, including mean productivity (MP), stress tolerance (TOL), stress susceptibility (SSI), stress tolerance index (STI) and geometric mean productivity (GMP) were used in this study. Data analysis revealed that the SSI, STI and GMP indices were the more accurate criteria for selection of heat tolerant and high yielding genotypes. The positive and significant correlation of GMP and grain yield under both conditions revealed that this index is more applicable and efficient for selection of parental inbred lines in producing hybrids to be tolerant to high temperatures and high yielding under both conditions. Based on two years’ data and using the STI, GMP and MP indices, K166B, K166A and K18×K166B proved to be the most heat tolerant lines and hybrid. Biplot analysis allowed us to distinguish groups of tolerant and sensitive inbred lines and hybrids. Based on the results of this study, the hybrid K18×K166B can be recommended for the Khuzestan region.
Volume 25, Issue 5 (9-2023)
Abstract
The genus Stachys L., (Lamiaceae family) has several spicy and aromatic species. In order to investigate the diversity of aerial biomass, morphological traits, and essential oil yield, 47 populations out of five species including S. lavandulifolia, S. laxa, S. inflata, S. germanica and S. byzantina were evaluated during two years, at a research farm in Khorramabad, Iran. The traits such as plant height, leaf length, leaf width, stem number, stem diameter, vegetation cover, 1,000 seed weight, and aerial dry (DM) yield in all 47 populations were measured. The essential oil was extracted using the hydrodistillation method with a Clevenger-type apparatus. The essential oil compounds were detected using GC and GC/MS. Data were analyzed using nested ANOVA with Minitab16 software. The results showed that both S. germanica and S. byzantina had higher aerial biomass than the other species. The Saveh and Tehran populations of S. inflata, the populations of Qazvin and Qorveh in S. lavandulifolia, and the populations of Ardebil and Semirom in S. Byzantine were superior to the others for the measured traits. For essential oil yields (w/w), the highest and lowest values were 2.0 and 0.8%, obtained in S. byzantina and S. lavandulifolia, respectively. Phytochemical analyses of S. lavandulifolia identified 43 compounds. The main compounds were β-eudesmol (3.48%), germacrene-D (4.59%), δ-cadinol (4.69%), bicyclogermacrene (6.85%), δ-cadinene (9.69%), spathulenol (10.08%) and α-cadinol (12.86%). S. lavandulifolia, with early maturity and higher essential oil, was recommended for domestication and breeding of improved varieties.
