Medicinal and Aromatic Plants - vol 45 - Turmeric- The Genus Curcuma

16 Turmeric: The Genus Curcuma
2.9 Genetic Resources ..................................................................................................................41
2.9.1 Cultivar Diversity .......................................................................................................42
2.9.2 Variability ...................................................................................................................44
2.10 Crop Improvement..................................................................................................................55
2.10.1 Selection .....................................................................................................................55
2.10.2 Mutation Breeding......................................................................................................59
2.10.3 Somaclonal Variation..................................................................................................59
2.10.4 Hybridization ..............................................................................................................59
2.11 Future Strategy .......................................................................................................................59
References ........................................................................................................................................59
2.1 INTRODUCTION
Curcuma, a very important genus in the family Zingiberaceae, consists of about 110 species,
distributed in tropical Asia and the Asia–Pacific region. The greatest diversity of the genus occurs
in India, Myanmar, and Thailand, and extends to Korea, China, Australia, and the South Pacific.
Many species of Curcuma are economically valuable, the most important being Curcuma longa,
known as turmeric commercially. In spite of its economic importance, the genus is poorly understood,
botanically and chemically.
In addition to C. longa, the genus includes other economically important species such as C.
aromatica, used in medicine and in toiletry articles; C. kwangsiensis, C. ochrorhiza, C. pierreana, C.
zedoaria, C. caesia, etc., used in folk medicines of the Southeast Asian nations; C. alismatifolia, C.
roscoeana, etc., having floricultural importance; C. amada, used as a vegetable in a variety of culinary
preparations, pickles, and salads; and C. zedoaria, C. malabarica, C. pseudomontana, C. montana,
C. decipiens, C. angustifolia, C. aeruginosa, etc., used in the production of arrowroot powder.
This chapter summarizes the available information on botany, genetic resources, and crop
improvement aspects of turmeric.
2.2 TAXONOMY
2.2.1 CURCUMA L.
Linn. Sp. Pl. 2, 1753; Gen. Pl. ed. 5.3:1754; Roxburgh, Asiat. Res. 11:338, 1810; Fl. Indica. 1:20,
1820; Bentham in Bentham & Hooker f. Gen. Pl. 3:643, 1883; Dalzell & Gibson, Bombay Fl. 274,
1861; Baker in Hooker f. Fl. Brit. India 6:209, 1890; Trimen, Handb. Fl. Ceylon 4:240, 1898;
Schuman in Engler, Pflanzer. 4(46):99, 1904; Cooke, Fl. Pres. Bombay 2:729, 1907; Fyson, Fl.
Nilgiri & Pulney Hill Tops, 1:408, 1915; Fl. S. Indian Hill Stations 2:597, 1932; Fischer. Rec. Bot.
Sur. India 9:177, 1921; in Gamble, Fl. Pres. Madras 8:1481, 1928; Ridley, Fl. Malay Penin. 4:253,
1924; Holttum. Gard. Bull. Singapore 13:65, 1950.
Holttum (1950) gives the following description for the genus Curcuma:
Rhizome fleshy, complex, the base of each aerial stem consisting of an erect, ovoid or ellipsoid
structure (Primary tuber), ringed with the bases of old scale leaves, bearing when mature several
horizontal or curved rhizomes, which are again branched. Roots fleshy, many of them bearing ellipsoid
tubers. Leaf shoots bearing a group of leaves surrounded by bladeless sheathes, the leaf sheaths
forming a pseudostem; total height of leafy shoots 1 to 2 m. Leaf blades usually more or less erect,
often with a purple-flushed strip on either side of the midrib; size and proportional width varying
from the outermost to the innermost (uppermost) leaf. Petioles of outermost leaf short or none, of
inner leaves fairly long, channeled. Ligule forming a narrow up-growth across the base of the petiole,
its ends joined to thin edges of the sheath, the ends in most species simply decurrent, rarely raised
as prominent auricles. Inflorescence either terminal on the leaf shoot, the scape enclosed by the leaf