Aram Sharifi-Zagheh; Amir Gholizadeh; Behzad Sorkhilalehloo; Mostafa Khodadadi
Abstract
Development of drought-tolerant cultivars with high essential oil yield is important for production of medicinal plants. So far application of half-sib mating has not been used in the coriander breeding for high essential oil yield and drought tolerance. In this study, 14 half-sib families of coriander ...
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Development of drought-tolerant cultivars with high essential oil yield is important for production of medicinal plants. So far application of half-sib mating has not been used in the coriander breeding for high essential oil yield and drought tolerance. In this study, 14 half-sib families of coriander derived from poly-cross design were evaluated under three irrigation treatments including: well water, mild water deficit stress and intense water deficit stress. In each environment, the half-sib families were evaluated using a randomized complete block design with three replications. Six drought-tolerance indices, including stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HM), stress tolerance (TOL) and stress susceptibility index (SSI) were calculated based on essential oil yield under non-stress (YP), mild stress (YM) and intense stress (YS). The results of correlation coefficients and biplot analysis revealed that STI, GMP, MP and HM indices could be effectively used for screening of drought tolerant genotypes of the coriander. Selection by these indices can be useful to identify a genotype with desirable essential oil yield in both non-stress and stress conditions. According to the results of three-dimensional graphs and view of biplot, half-sib families’ No. 6, 7 and 14 under mild stress and half-sib families’ No. 6, 7 and 12 under intense stress were selected as drought tolerant, and with high essential oil yield under non-stress and stress conditions. Therefore, these half-sib families can be used as a source of elite parents for synthetic cultivars in the coriander.
Mohsen Ashrafi; Mohammad Reza Azimi Moqadam; Parviz Moradi; Farid Shekari; Ehsan MohseniFard
Abstract
Drought as the most important abiotic stress has deleterious effects on plants. Developing drought tolerant varieties can help produce plants in a sustainable way. This study was conducted to identify drought tolerant and drought sensitive thyme species including Thymus vulgaris, T. vulgaris (origin: ...
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Drought as the most important abiotic stress has deleterious effects on plants. Developing drought tolerant varieties can help produce plants in a sustainable way. This study was conducted to identify drought tolerant and drought sensitive thyme species including Thymus vulgaris, T. vulgaris (origin: Spain), T. carmanicus, T. daenensis and T. kotschyanus and to study the mechanism used by them to cope with drought stress. For this purpose, relative water content, water use efficiency, soil water depilation rate, root:shoot ratio, drought resistance index and a new criterion "FC ceased growth" were used. T. carmanicus and T. daenensis had the lowest and the highest reduction on relative water content, respectively. In terms of water use efficiency and soil water depletion curve, the highest and the lowest values were detected for T. daenensis and T. carmanicus, respectively. The most and the least root:shoot ratios were recorded for T. daenensis and T. vulgaris (origin: Spain), respectively. Analyses by drought resistance index and PCA revealed that T. carmanicus is drought susceptible, T. kotschyanus and T. vulgaris are semi-drought susceptible, and T. daenensis and T. vulgaris (origin: Spain) are semi-drought tolerant species. FC ceased growth analysis showed that T. carmanicus stopped its growth at higher FC, while T. kotschyanus stopped it at lower FC. Therefore, based on this criterion and considering the sustainability of growth under drought condition, T. carmanicus and T. kotschyanus are the least and the most drought tolerant Thymus species.