Document Type : Original Article

Authors

• Amir GHolizadeh ¹
• Hamid Dehghani ²
• Mostafa Khodadadi ³

¹ TMU

² Professor in Genetics and Plant Breeding Department, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

³ Ph.D graduated in Genetics and Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

Abstract

Introduction
Coriander is an annual herb belongs to the umbel family and is native from North Africa to south-western of Asia. Coriander is one of the important medicinal plants that used in the pharmaceutical industry and it mainly cultivated and widely distributed for the fruits. The dried fruits are widely employed as a condiment, especially for flavoring of sauces, meat products and bakery and confectionery items. Also, coriander fruits are as a source of essential oils and fatty oil. Water deficit stress is one of the most important factors limiting the growth and survival of the plants in arid and semi-arid regions in the world. Water is a major component of the plant materials and significantly influence the quantity and quality of plant production. Drought stress leads to significant changes in the yield and composition of essential oils in aromatic and medicine plants. So that, it was reported that water deficit increased essential oil content but decreased essential oil yield in coriander. Iran with an average annual rainfall of 240 mm is classified as arid and semi-arid regions of the world. However, Iran is one of the world’s commercial coriander producers. Coriander has been cultivated for many years in different parts of Iran. Therefore, development of drought-tolerant cultivars with high essential oil and fatty oil yield is important in coriander. Indirect selection through yield components and yield-related traits is one of the most effective methods for improving complex traits such as fruit yield. Therefore, this research was conducted in order to understand the genetic association between quantitative and qualitative traits and also to identify the indirect selection indices for selection appropriate genotypes in coriander.

Materials and Methods
F1 and F2 generations derived from half-diallel crosses between six endemic coriander genotypes including Isfahan, Hamedan, Bushehr, Mazandaran, Markazi and Alborz, along with with their parents were evaluated in three irrigation regimes through randomized complete block design with three replications in each experiment during the growing season in 2016. Plants were grown in different irrigation regimes: well-watered (WW), moderate drought stress (MDS) and severe drought stress (SDS). The plant height, leaf number, branch number per plant, umbel number per plant, fertile umbel number per plant, fruit number per plant, thousand fruit weight, fruit yield, biological yield, essential oil content, fatty oil content, essential oil yield, fatty oil yield, SPAD chlorophyll content, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, relative water content and ion leakage were measured.

Results and Discussion
Results showed that fruit yield had the significant positive genetic correlation with days to flowering, SPAD chlorophyll content, relative water content, fruit number per plant and thousand fruit weight. Therefore, these traits could be used as suitable criterion for selection to increase fruit yield in drought stressed conditions. Consideration, the genetics of early ripening and fruit yield and a significant positive genetic correlation between days to ripening and fruit yield, improving coriander fruit yield under drought stress may be possible through breeding for drought escape. There were the positive genetic correlations between fruit yield and other economical traits in different irrigation regimes. Therefore, improving fruit yield can simultaneously be led to improve in the economical traits.

Conclusion
Generally, the results indicated that traits of days to flowering, SPAD chlorophyll content, relative water content, fruit number per plant and thousand fruit weight could be used as suitable criterion for selection to increase fruit yield in drought stressed conditions. Also, improving fruit yield can simultaneously be led to improve in the economical traits in both the non-stressed and drought stressed conditions

Keywords

• Early maturty
• Genetic correlation
• Indirect selection
• Narrow-sense heritability