Rice

Rice: Taxonomy, morpho-anatomy and yield perspective

M A Baset Mia
Department of Crop Botany
Bangabandhu Sheikh Mujibur Rahman Agricultural University
Gazipur 1706, Bangladesh
E-mail: miabaset@bsmrau.edu.bd

Common name: Rice/Paddy

Scientific name: Oryza sativa L.

Local name/ (বাংলা নাম) : ‘Dhan’/ (ধান)

Taxonomic Position According to Cronquist (1988)

Botanical Description of Rice Plant

Habit: Annual herb

Root: Fibrous root system, rootlet and root hair present. The first form root is called seminal root, which is parsley branched and persist for a short time after germination. New roots are emerged soon after the destroyed of seminal root. The prop roots are arisen from the node of the above ground.

Stem: Hollow, cylindrical composed of node and internode, and called culm. Leaf and buds are arisen from the node. The tillers are arisen from the lower nodes as alternate manner.

Fig. Root Anatomy of Rice

Fig. Stem Anatomy of Rice

Leaf: simple, sessile composed of leaf sheath and leaf blade. Leaf sheath encircled the stem, and the leaf blade is flat. At the junction, a feathery structure is known as ligule and thread like structure is known as auricle. Auricles are ear-like appendages arises in pair from both sides. The terminal leaf is known as flag leaf.

Fig. Leaf Anatomy of Rice

Inflorescence: terminal, panicle.

Fig. Inflorescence of Rice

Spikelet: born on the pedicel which is morphologically a peduncle. The spikelet consists of a minute axis (rachilla) on which a single floret is borne in the axils of 2-ranked bracts. The bracts of the lower pair on the rachilla, being always sterile, are the sterile lemmas (“glumes,” “empty glumes,” “outer glumes”). The upper bracts or the flowering glumes consist of the lemma (fertile lemma) and palea. The lemma, palea, and the included flower form the floret. The filiform extension of the keel of the lemma is known as awn.

Flower: It is known as floret contains bracts lemma and palea. Flower is bisexual and zygomorphic.

Perianth: The calyx and corolla together form perianth and is known as lodicule. The lodicules are two wale-like, transparent, fleshy structures located at the base of the flower adnate to the palea.

Androecium: Stamens are six, located into two whorls, anther versatile.

Gynoecium: Carpel one, placentation basal, stigma feathery.

Fruit: Caryopsis, the rice fruit is a caryopsis in which the single seed is fused with the wall of the ripened ovary (pericarp), forming a seed like grain. The grain is the ripened ovary, with the lemma, palea, rachilla, sterile lemmas, and the awn, if present, firmly adhered to it. The lemma and palea and their associated structures such as the sterile lemmas, rachilla, and the awn whenever present constitute the hull or husk.

Rice seed: rice grain, commonly called a seed, consists of the true fruit or brown rice (caryopsis) and the hull, which encloses the brown rice. Brown rice consists mainly of the embryo and endosperm. The surface contains several thin layers of differentiated Tissues that enclose the embryo and endosperm. The palea, lemmas, and rachilla constitute the hull of indica rices.

Table 1 Rice varieties developed by BRRI, Joydebpur, Bangladesh

Table 2. Rice varieties developed by BINA, Mymensingh, Bangladesh

Table 3. Rice varieties developed by BAU, BSMRAU

 Table 4. Local Rice Varieties Grown in Bangladesh (বাংলাদেশে আবাদযোগ্য স্থানীয় জাত সমূহ)

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