Rice Production: Chapter 3 - Varietal characteristics

Introduction

A vast number of rice varieties is grown around the world. While it is true that no "perfect" variety exists, for every combination of environmental features, management practices, and farmer preferences it is usually possible to select a suitable variety. This chapter describes the kind of things to look at when you select a rice variety. Like the farmer, you will find yourself relying both on tradition and on trial and error The traditional varieties provide the security of known response that have proven themselves over the years. The trials and errors are what make the work creative and offer the cope of improvement.

I. Varietal Characteristics

Listed below are the varietal characteristics most often considered by farmers in selecting a rice variety for cultivation:

a) Duration - most cultivated varieties range from 90-270 days in duration (germination to harvest) Importance:

*determines how many crops can be grown in one year

*important in coordinating the growing season with the availability of water

*important in coordinating the farming calendar with other family subsistence activities.

b) Height of the Plant - rice varieties are generally classified by height as follows:

tall	161 cm - 350 cm	(63" - 140")
medium	75 cm - 160 cm	(30" - 62")
short	below 75 cm	(below 30")

Importance:

*determines crop's ability to withstand deep flooding

*affects harvesting practices

c) Stature of the Plant - rice varieties are generally classified by stature as follows:

spreading

slightly spreading

spreading

Importance:

*affects spacing during planting

*determines plant's ability to shade out competing weeds.

d) Tillering Capacity - rice varieties are said to be either: high tillering (each seed produces 26-35 tillers)

medium tillering ( each seed produces 10-25 tillers)

low tillering (each. seed produces 2-10 tillers)

Importance:

*directly affects yield

*determines planting practices

*determines amount of seed nursed

*affects plant's ability to recover from damage inflicted by pests or weather.

e) Panicile Size/Grain Weight

Importance:

*directly affects yields

f ) Resistance to Toxicities

Importance:

*determines suitability to local soil and water conditions

g) Resistance to Pests/Diseases

Importance:

*determines suitability to local rest/disease conditions

h) Response to Fertilizer - many improved varieties have been bred to respond favorably to fertilization with chemical fertilizers, i.e. they show a marked increase in growth rate, height, number of tillers, panicle size, and grain weight.

Importance:

*should be compatible with farmer's fertilization practices (or non-fertilization practices).

i) Milling and Cooking Characteristics - depending on the nature of the husk, rice varieties may be either easy or difficult to mill. Furthermore, cooked rices vary considerably in appearance, texture, taste, smell, and starch content.

Importance:

*significantly affects farmer's preferences

II. Traditional vs. Improved Varieties

In many parts of the world, farmers have been growing rice for hundreds or even thousands of years. During this time, many varieties have interbred or mutated and gradually adapted to local conditions. Conversely, through trial and error farmers have developed traditions of cultivation practices which assure consistent fair yields with relatively little management. The majority of subsidence farmers still rely on time-honored management practices -to cultivate their traditional varieties. Characteristics typically found in such varieties include:

- long, duration

- high tillering

- spreading stature

- resistance to drought/flooding;

- resistance to pests/diseases

- competitive with weeds

- adapted to low nutrient levels

- high milling and cooking quality.

Although the traditional varieties usually yield lower than the improved -varieties, the extension agent should be extremely careful about suddenly encouraging farmers to abandon a time-tried variety for one which differs considerably from what they are used to growing The single most important characteristic of most traditional varieties is their ability to produce sustained yield, however modest. The introduction of a new "miracle" variety, even if advantages is initially, may prove disastrous in the long run if the farming system over time proves incapable of providing the nutrient inputs necessary for the production Or sustained high yields. As a rule, high yields require high (fertilizer) inputs, and it is easy to make the mistake of either creating a fertilizer dependency or depleting a balanced farming ecosystem by introducing a variety which extracts nutrients faster than they are being replenished. The extension agent should not be afraid to experiment with new varieties - but s/he must be careful not to encourage the farmer to succumb to the short-sighted temptation to maximize present yields. The traditional varieties, however low-yielding, have endured over thousands of years because they are hardy, reliable, and ecologically safe.

III. Chart - Locally Available Varieties

Format chart for local varieties