Document Type : Research Paper

Authors

• Mehdi Hadadi Nejad ¹
• hamidreza fanaei ²
• NadAli Bagheri ³
• Manni Marefatzadeh-Khameneh ⁴
• Noosheen Rahmani ³

¹ Horticulture Science, Sari Agricultural Sciences and Natural Resources University, Sari, Iran

² Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.

³ Horticulture Science, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.

⁴ Department of Genetics and National Plant Gene Bank of Iran, SPII., AREEO, Karaj, Iran

Abstract

Objective: The global shift toward phytotherapy has made the conservation of medicinal plant species critically important. One challenge in developing black cumin cultivation is the limited knowledge of traits influencing yield improvement, as well as the lack of populations or improved cultivars with suitable agronomic characteristics adapted to diverse ecological conditions. This research aimed to investigate the genetic diversity of native black cumin ecotypes using morpho-phenological markers and to identify suitable genotypes for cultivation in the Karaj region.
Methods: Twenty native ecotypes were evaluated in a randomized complete block design (RCBD) with three replications during the 2021-2022 growing season at the research farm of the Seed and Plant Improvement Institute (SPII) in Karaj, Iran.
Results: Analysis of variance revealed significant diversity among ecotypes for phenological traits (days to flowering and maturity), plant height, yield, and yield components (number of follicles per plant, number of seeds per follicle, and thousand-seed weight). Mean comparisons using Duncan's multiple range test (P ≤ 0.05) showed that the highest seed yield was recorded in ecotypes with the greatest longitudinal and transverse follicle diameters, highest number of follicles per plant, highest number of seeds per follicle, and highest thousand-seed weight. The lowest and highest seed yields belonged to ecotypes TN-82-191 (946 kg/ha) and TN-82-750 (1749 kg/ha), respectively, representing a 45.88% difference. Furthermore, ecotype TN-82-750 showed a 26.08% superiority over the average yield. Seed yield displayed a significant positive correlation with follicle length (r= 0.67), number of follicles per plant (r = 0.84), and number of seeds per follicle (r= 0.60). Cluster analysis grouped the ecotypes into three distinct classes. The first group contained late-flowering and late-maturing ecotypes with higher stem branch numbers, plant height, and follicle diameter. The second group exhibited the highest seed yield, which was possibly attributable to a longer seed-filling period (i.e., the interval between flowering and seed maturity). Factor analysis indicated that the first three factors accounted for 73.90% of the total variation, named as morpho-phenological traits factor, yield and yield components factor, and longitudinal growth index factor, respectively.
Conclusion: Ecotype TN-82-750 was identified as an early-maturing, high-yielding sample; TN-82-691, TN-59-224, and IPK as medium-maturing; and TN-59-254 as a late-maturing, high-yielding ecotype. These ecotypes can be recommended for different regions depending on available water and input conditions. Overall, a high potential for genetic diversity was observed among the ecotypes, which—given their native status and high adaptability—can serve as a valuable genetic resource in breeding programs.

Keywords

• Breeding strategies
• Cluster analysis
• Germplasm
• Morpho-phenological diversity