Biologia, Bratislava, 62/1: 19—23, 2007 Section Botany DOI: 10.2478/s11756-007-0001-z Gynomonoecy in Chenopodium quinoa (Chenopodiaceae): variation in inflorescence and floral types in some accessions Atul Bhargava, Sudhir Shukla & Deepak Ohri* Division of Genetics and Plant Breeding, National Botanical Research Institute, Lucknow–226001, India Abstract: Inflorescence structure and floral morphology has been studied in 19 accessions of C. quinoa. All the accessions show gynomonoecy and bear three basic flower types viz. hermaphrodite, chlamydeous female and achlamydeous female and number of types can be extended to five considering the size of flowers. Ten types have been classified on the basis of the proportion of hermaphrodite and female flowers and their arrangement, depending upon the number of divisions of the dichasium on the glomerule. Implications of these results in facilitating intervarietal crosses are discussed. Key words: C. quinoa; inflorescence; floral types; glomerule; gynomonoecy Introduction Quinoa (Chenopodium quinoa Willd.) is a pseudoce- real that has been used as an important grain crop in the Andean region since 3000 B.C. (Tapia 1982; Koziol 1993). Quinoa grain is a rich source of oil, starch, min- erals and vitamins, besides having an outstanding pro- tein quality (Koziol 1992; Oshodi et al. 1999; Ogung- benle 2003). The plant also has the ability to resist various abiotic stresses like soil salinity, frost, drought etc. (Jensen et al. 2000; Jacobsen et al. 2003). Due to its wide adaptability, the plant has been successfully in- troduced and acclimatized in various parts of the world like Europe, Africa and Asia (Mujica et al. 2001). Increasing grain yield of quinoa has been the prin- cipal aim of quinoa breeders worldwide. This requires a first hand knowledge of the floral structure and the breeding system of the flower, including the arrange- ment of flowers on the inflorescence. Many types of flowers are known to occur that range from unisex- ual to hermaphrodite (Risi & Galwey 1984). Inspite of the long history and recently evoked interest in the plant, studies on floral structure and breeding system in quinoa are rare (Risi & Galwey 1984). Therefore, the present study was undertaken to study the structure and the arrangement of various types of flowers on the inflorescence. Material and methods The accessions used in the study and their sources are given in Table 1. The inflorescences were collected at the same stage of growth from three plants of each accession grown under similar environmental conditions. The inflorescences were studied under a dissecting microscope. Results All the C. quinoa accessions studied are gynomonoe- cious i.e. the female and perfect flowers are present on the same individual. The inflorescence is a panicle, which is usually profusely branched having a princi- pal axis from which secondary and tertiary branches arise. Besides the terminal inflorescence, there are ax- illary inflorescences, which arise from the leaf axils on the lower parts of the plant and these show determinate growth being terminated by a hermaphrodite flower. The elongation of the inflorescence is due to the in- tercalary growth of the axis. Short branches bearing a group of flowers originate from third order (tertiary) axes, which are called glomeruli. The secondary and tertiary branches also bear a terminal hermaphrodite flower. Floral structure: The flowers can be divided into five types based on their being hermaphrodite or female, presence or absence of perianth and size. I. Terminal hermaphrodite flower: This is the termi- nal flower, 2 mm in breadth present on the main and axillary inflorescences, and on each cluster or group of flowers on the inflorescence. The number of perianth segments may vary from 5 to 6 with as many anthers. II. Lateral hermaphrodite flower: These are dispersed among the female flowers and are present termi- nally on the first, second or even third branching of the dichasium. These generally have pentamer- ous perianth and stamens. III. Chlamydeous female flowers-large: These have 5- * Corresponding author: ohri deepak@rediffmail.com c 2007 Institute of Botany, Slovak Academy of Sciences Unauthenticated Download Date | 7/27/18 8:45 AM