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2.7. Spikelet A spikelet is a unit of the rice inflorescence borne on the pedicel which is morphologically a peduncle. It consists of two sterile lemmas, the rachilla, and the floret. The rachilla is the small axis between the rudimentary glumes and the fertile floret. The floret includes the lemma, palea, and the enclosed flower. The flower consists of six stamens and a pistil. The six stamens..

2.6. Panicle The major elements of a panicle are the base, axis, primary and secondary branches, pedicel, and spikelet. The panicle is borne on the uppermost internode of the culm. The extent to which the panicle and a portion of the uppermost internode extend beyond the flag leaf sheath determines the exsertion of the panicle. Varieties deffer in degree of exsertion and environmental condition..

2.5. Culm A culm is a jointed stem of rice made up of a series of nodes and internodes. The node is solid portion of the culm. The node or nodal region bears a leaf and a bud. From the axils of nodes on the culm may arise a leaf, a tiller, or crown roots. The bud is between the node and the base of a leaf sheath. The bud may give rise to a tiller. Internodes are the elongated parts between two ..

2.3.5. Leaves as food factories Leaves are the carbohydrate factories of rice plants. They are necessary for the interception and transformation of light energy to growth and yield. A leaf is the major organ for the photosynthesis. The photosynthesis takes place in mesophyll cell containing chloroplasts. Many mesophyll cells exist inside a leaf. Water from the soil and carbon dioxide from the a..

2.3.4. Growth of leaves The rice plant is composed of leaves that are physiologically different in age and activity. Leaves grow in sequence at the relatively fixed rate. A leaf emerges about every 5 to 6 days before the initiation of panicle primordia. However the last four to five leaves usually emerge 7 to 8 days. And the leaves are alternately arranged. The rate of leaf emergence is affecte..

2.3.3. Leaves of mature plant Rice plant commonly produces 14-17 leaves on the main shoot. These leaves are counted upward in order of their emergence. Therefore the leaf developing next to coleoptile is called the first leaf. The uppermost, last formed leaf is called the flag leaf or boot leaf. The number of leaves on the main culm is genetically determined according to different rice varietie..

2.3.2. Leaves of rice seedling Morphological structure of rice seedling during the short period after gemination is regarded as a transitory process from its status in the growth stage of embryo and germination to that of an adult. The coleoptile emerges at germination and grow about one cm. It is followed by the first leaf. The first leaf is often called an 'incomplete leaf' ..

2.3.1. The rice leaf A typical rice leaf is composed of leaf sheath, leaf blade, collar, ligule, and a pair of auricles. A leaf sheath is the basal part of the leaf originating from a node. It encloses the internode above it and sometimes the leaf sheath and blades of the succeeding internode. The leaf blade has a midrib with large and small parallel veins on both sides of it.The collar is the ..

2.4.3. Root functions Roots as major vegetative organs supply water, minerals, and substances essential for rice growth and development. Roots serve the rice plant in the following important ways which are absorption, anchorage, and transport. The absorption of water and minerals occurs primarily through the roots tips and hairs. Root hairs are tubular extensions on the outerm..

2.4.2. Crown roots Crown roots develop from each nodal portion higher in position than the coleoptile node. And they come out in order from the lower to the higher node. Many crown or adventitious roots emerge almost simultaneously around the node. Therefore they are crown-shaped, so the name is crown. They are growing from the rooting band just above and below the node in the case of rice. Cro..