Question

A remarkable increase in rice production from $35$ million tonnes to $89.5$million tonnes during $1960 - 2000$ was mainly due to
(A) Improved semi dwarf varieties
(B) Introduction of golden rice
(C) Increased use of chemical fertilizers
(D) Cultivation of wild varieties

Answer 1

During$1960 - 2000$, a remarkable enhancement in the production of rice from $35$ tons to $89.5$ tons was observed mainly due to significant improvement in the semi dwarf varieties.

Complete answer:
- Some of the semidwarf varieties of rice such as m IR-8 and Taichung Native-$1$ were developed in$1966$. These semidwarf varieties exhibited immense properties and significantly enhanced the rice production during $1960 - 2000$.
- Moreover, as compared to the dwarf varieties the semi dwarf varieties exhibited smaller sized rice varieties and also showed increased production. Somehow the development in the semidwarf varieties of rice has shown significant revolution in cultivation of rice.
- The semi dwarf varieties of rice have an ability to resist water lodging, improved response for fertilizers, increased yield and high photosensitivity.
- In initial days, Dr. Khush developed $IR36$ (a semi dwarf variety of rice) by cross-breeding IR$8$ variety with thirteen varieties of parent types of rice isolated from $6$ different nations.
- The developed semi dwarf variety showed improved resistance towards major insects and diseases that elevated the yield of rice.
- The semi dwarf varieties have been derived from various parts of the countries. Some of the dwarf varieties include dee-geo-gen, of Japonica rice found in Taiwan.
- Apart from this, Taichung Native $1$ (TN$1$) was developed in Taiwan and IR$8$ was developed in Philippines, which later on were established in India. But after a few years these dwarf varieties were replaced with more developed semi dwarf varieties such as Jaya, Rama, and others found in India.

Note: The golden rice is a variety of rice that was developed with the help of genetic engineering technologies. This technique was used in the biosynthesis of beta-carotene in the edible parts of rice. On the other hand, the wild rice variety also recognized as Indian rice or water oats, is occasionally grown.