TANAMAN PADI

RICE

Rice (Latin: Oryza sativa L.) is one of the most important crops in civilization. Although it primarily refers to the type of crop, riceis also used to refer to several types ofgenera (genus) of the same, which is commonly referred to as wild rice. Rice thought to have come from India or Indochina and into Indonesia carried by ancestorswho migrated from mainland Asia around 1500 BC. Worldrice production ranks third of all cerealafter maize and wheat. However, rice is themain source of carbohydrates for the majority of the world's population. The results of processing of paddy rice called.

CHARACTERISTIC FEATURES OF

Rice is included in the rate of grain or Poaceae. Terna annuals, fibrous roots, stems very short, rod like structure formed of a series of mutually supporting leaf midrib perfectly with the leaf sheath erect, lancet-shaped leaves, light green to dark green, parallel veined leaves, covered with short hair and sparse, the flowers arranged compound, branched panicle type, unit of flowers called florets spikelet located at one sitting on panikula, the type of grain or fruit that can not be distinguished kariopsis where fruit and seeds, almost round to oval shapes, sizes 3mm to 15mm, covered by palea and lemma which in everyday language is called chaff, the dominant structure of the usual rice dikonsuksi the type enduspermium.

REPRODUCTION

Each rice flower has six anthers (anther) and the stigma (stigma) forked shaped brush botol.Kedua sexual organs are generally ready to reproduce in a sari bersamaan.Kepala sometimes out of the palea and lemma if it has been cooked. In terms of reproduction, rice is berpenyerbukan plant itself, because 95% or more pollen to fertilize the egg of the same plant. After fertilization occurs, the zygote and the fertilized polar nuclei split soon developed diri.Zigot polar nuclei to form the embryo and become endosperm.Pada end development, mostly starch grains mengadung section endosperm.Bagi young plants, starch is used as a source of nutrition.

GENETICS AND BREEDING

A set of rice genome consists of 12 chromosomes. Since rice is a diploid plant, each cell has 12 pairs of chromosomes of rice (except sex cells). Rice is a model organism in plant genetics study for two reasons: its importance to mankind, and the relatively small size of the chromosomes, which is 1.6 ~ 2.3 × 108 base pairs (base pairs, bp) [2]. As a model plant, the rice genome has been sequenced, as well as the human genome.

Genetic improvement of rice has been going on since humans cultivate rice. From the results of this action is the knowledge of a wide range of local races, such as the 'Rajalele' from Klaten or 'Pandanwangi' of Cianjur in Indonesia or 'Basmati Rice' from northern India. People also successfully developed upland rice (upland rice) that do not require inundation or swamp rice that is able to adapt to the swamp water depth changes. In other countries also developed various types of rice.

New rice breeding systematically carried out since the establishment of IRRI in the Philippines as part of the modernization of the agricultural world, dubbed the Green Revolution. Since then arise various rice cultivars with high yield to feed the world. Two of the first modern rice cultivars is 'IR5' and 'IR8' (in Indonesia adapted into 'PB5' and 'PB8'). Although the results are high but many farmers refused because it was not tasty (pera). In addition, the outbreak of brown planthopper in the 1970's.

Thousands of crosses then designed to produce cultivars with high yield potential and resistance to various pests and diseases of rice. In 1984, the Indonesian government had won an award from the United Nations (FAO) for successfully increasing rice production in 20 years to be transformed from the world's biggest rice importer into the country self-sufficient in rice. This achievement can not be continued and new rebounded since 2007.

The presence of biotechnology and genetic engineering in the 1980's enabling improved quality of rice. Several teams of researchers in Switzerland developed a transgenic rice that can produce toxins for pest-eating grain in the hope of lowering the use of pesticides. IRRI, in collaboration with several other institutions, assemble "golden rice" (Golden Rice) that produce provitamin A in rice, which is directed to the alleviation of vitamin A deficiency in developing countries. A team of researchers from Japan are also developing rice that produces cholera toxin to bacteria [3]. It is expected that the resulting rice paddy cholera immunization may be an alternative, especially in developing countries.

Since the 1970's have cultivated the development of hybrid rice, which has a higher yield potential. Due to high manufacturing costs, cultivar types are sold at higher prices than rice cultivars that are assembled with other methods. In addition to improved yield potential, rice breeding objectives also includes plants that are more resistant to various pests of plants (OPT) and the pressure (stress) abiotic (such as drought, salinity, and acid soils). Breeding aimed at improving the quality of rice was also carried out, for example by designing cultivars containing carotene (provitamin A).

GENETIC DIVERSITY

Until now there are two species of humans cultivated rice in bulk: Oryza sativa originating from Asia and O. glaberrima originating from West Africa.
In the beginning O. sativa is considered consists of two subspecies, indica and japonica (synonym Sinica). Japonica rice are generally long-lived, high stature yet easy to fall, lemmanya has a "tail" or "feather" (Ing. awn), seeds tend to be rounded, and sticky rice. Indica rice, by contrast, lived shorter, smaller stature, lemmanya not air-"feather" or just short of it, and the grains tend to be oval to oblong. Although both members of this subspecies are able to fertilize, the percentage of success is not high. Famous example of this is a hybrid cultivar 'IR8', which were selected from a cross japonica (cultivar 'Deegeowoogen' Formosa) and indica (cultivar 'Map' of Indonesia). In addition to these two varieties, known javanica minor varieties which have properties between the two main types of the above. Javanica varieties found only on the island of Java.

Studies with the help of molecular biological techniques have now shown that in addition to the two subspecies of O. The main sativa, indica and japonica, but there are also minor subspecies adaptive Tempatan, such as wear (upland rice from Bangladesh), royada (pasang-surut/rawa rice from Bangladesh), Ashina (tidal rice from India), and aromatic (fragrant rice from South Asia and Iran, including the famous basmati rice). The grouping was done using RFLP marker assisted with isozymes. [4] study using genetic markers SSR to the nuclear genome of cells and two loci on the chloroplast genome suggests that indica and japonica differentiation is steady, but it turns japonica typically divided into three groups: temperate japonica (" japonica cool region "of China, Korea, and Japan), tropical japonica ('japonica tropical regions" of the archipelago), and aromatic. Subspecies wear a separate group.
     Based on the evidence of molecular evolution estimated indica and japonica large group separate from ~ 440,000 years ago from an ancestral population of species O. rufipogon. [5] rice domestication occurred in a different spot where the two groups are separate. Based on archaeological evidence of rice began to be cultivated (domesticated) 10,000 to 5,000 years BC