Authors: Madhu Choudhary*, Kana Ram Kumawat, Ravi Kumawat and Pushpa kumari Yadav
Department of Plant Breeding and Genetics, S.K.N. Agriculture University, Jobner-303329, Jaipur (Rajasthan), India
*Corresponding Author E-mail: anamikaz0129@gmail.com
The ultimate aim of any breeding programme is to develop varieties superior to existing ones in yielding ability, disease and insect resistance and other characteristics. For commercial utilization, these strains have to be released as varieties by either the central or a state variety release committee. This release based on conclusive demonstration of the superiority of new strains over the best existing varieties in yield ability or in some other feature of economic importance, e.g. disease resistance, drought tolerance, salt tolerance etc. Therefore, new strains are extensively evaluated for performance, disease resistance and quality etc. in multilocation trials conducted under the concerned AICRP on various crops. But before the new strains are included in multilocation tests, the breeder should evaluate their performance at his own station to make sure that the new strain is superior to the existing varieties. The various activities and operations in the release of a strain as a variety may be grouped into the following three classes: (1) evaluation (2) identification and (3) release and notification.
Evaluation
Evaluation of a strain for release as a variety consists of various trials and tests to determine its superiority over the existing best variety in terms of yield and other agronomic traits and its suitability for consumption. In general, there are seven different types of trials/tests conducted during evaluation:
- Station Trial Station trial is conducted by the breeder who has developed the new strain(s); it is often referred to as preliminary yield trial and may be conducted for one or more years. The objectives of station trial are to make sure that the new strains developed by breeder are superior in performance (at that location) to the best available variety for the region before their inclusion in the multiplication trials. Therefore, to avoid disappointment and rejection in the early stages of testing, the breeder should himself make sure of the superiority of his strains.
- Multilocation Trials These trials are conducted under the respective All India Coordination Crop Improvement Projects. The objectives of these trials are to evaluate the performance of newly developed strains at several locations distributed over a region. Since the soil and climatic (agro-climatic) conditions show a large variation from one region of the country to the other, the country has been divided into several agroclimatic zones; each zone consists of areas having similar agro-climatic conditions. The number of zones and the zoning pattern vary considerably from one crop to the other. The various trials conducted under the coordinated projects, particularly in the case of wheat, may be grouped into the following four categories:
- Initial Evaluation Trial (IET) A new strain is first included in an initial evaluation trial within the zone, in which it was developed. A strain included in IET or URT is commonly termed as an entry. The IET is conducted at 10-12 locations within a zone. IET may be conducted for one or more years; it is then promoted to URT if its performance is outstanding, otherwise it is rejected. The objectives of IET are to eliminate relatively inferior entries so that their number is reduced to a manageable size for URT evaluations.
- Uniform Regional Trials (URT) The URT for any entry is conducted under the same conditions, under which it was evaluated in IET. URT is conducted at 25-30 different locations within the zone and may be continued for one or more years. Every year, entries poor in yield and/or disease resistance are rejected and new entries are included on the basis of their performance in IET of the previous year.
- Agronomic Trials An entry showing superior performance in URT during the first year is included in Agronomic Trials of the respective AICRP. The purpose of Agronomic Trials is to determine the suitable dates of sowing and the optimum number of irrigations. The data from these trials are generally not essential for consideration of an entry for identification, although they are included in the proposals for identification.
- Model Agronomic Experiments These experiments are conducted under the AICRP. In Model Agronomic Trials, only those entries are included those have been identified for pre-release multiplication by the workshops of the respective coordinated projects. These trials are conducted at all the centres of the Coordinated Agronomic Research Projects in the concerned zone.
- National Trials The National Trials are conducted throughout the country in all the zones. The entries in national Trials comprise one entry from each zone that ranked first in that zone in URT of the previous year.
| Crop | Evaluation procedure | Conditions of testing |
| Cereals | ||
| Wheat | IET, 1 Yr | 1. Timely sown (15-25 Nov.) irrigated |
| URT, 2 Yr | 2. Late sown (15-25 Dec.) irrigated | |
| AT, 1 Yr | 3. Rainfed (around 31 Oct.) | |
| Rice | PVT, 2 Yr | 1. Rainfed (direct-seeded) |
| UVT, 2 Yr | 2. Transplanted | |
| AT, 1 Yr | 3. Direct-seeded | |
| 4. Deep water | ||
| 5. Saline/alkaline soil | ||
| 6. Aromatic, slender grain | ||
| Millets | ||
| Pearlmillet | UVT, 3 Yr | 1. Bajra variety trials |
| AT, 1 Yr | 2. Bajra hybrid trials | |
| Sorghum | PST, 1 Yr | 1. Hybrid sorghum trials |
| AST, 3 Yr | 2. Varietal sorghum trials | |
| AT, 2 Yr | ||
| Pulses | ||
| Gram | IET, 1 Yr | 1. Timely sown, irrigated |
| CVT, 2 Yr | 2. Late sown, irrigated | |
| AT, 1 Yr | 3. Bold-seeded, irrigated | |
| 4. Kabuli, timely sown, irrigated | ||
| Mungbean | IET, 1 Yr | 1. Kharif, timely sown, irrigated/rainfed |
| CVT, 2 Yr | 2. Spring, timely sown, irrigated | |
| AT, 1 Yr | 3. Summer,timely sown, irrigated | |
| Oilseeds | ||
| Mustard | IET, 1 Yr | 1. Timely sown, rainfed |
| CVT, 1 Yr | 2. Timely sown, irrigated | |
| NET, 1 Yr | ||
| AT, 1 Yr | ||
| Groundnut | 4 Yr++ | 1. Rabi, irrigated |
| 2. Kharif, rainfed |
The National Trials serve as IET for an entry in zones other than that, in which it was developed and tested in URT. The purpose of National trials is to evaluate outstanding entries of one zone in the other agro-climatic zones to see if they perform well in other zones as well.
- Adoptive Research Trials These are conducted on research stations or farms of state governments. The entries identified for pre-release multiplication by the workshop of the concerned coordinated project are included in these trials. The agronomic practices used in Adoptive Research Trials are the same for which the concerned entry has been identified. The data from these trials are considered for release of the identified entry as a new variety.
- Minikit Trials The Minikit Trials are conducted in the farmer’s fields. These trials are conducted along with the Adoptive Trials in the crop season following the identification of the entry for pre-release multiplication. The Minikit Trials are conducted under the supervision of Director, High Yielding Varieties, Ministry of Agriculture and Irrigation, Government of India. These trials are conducted at 300-400 places within a zone. The objective of Minikit Trials is to popularise the new variety among the farmers of the zone. It also serves, another purpose; the seed of a good new variety reaches the farmers one year earlier than its certified seed would be available in the market.
- Disease and Insect Tests Entries are evaluated for disease and insect resistance throughout the period of testing i.e. during IET as well as URT. Disease and insect resistance is tested both under natural as well as artificial epidemic conditions. The disease reaction tests for different diseases of various crops are carried out at different places where epidemics of the concerned diseases occur regularly. The place where a disease occurs at a high intensity i.e. in an epidemic form, every year are known as hot spots for that disease. In any case, susceptibility to a disease would lead to economic losses to the farmers and often would lead to the rejection of a variety. In view of these, disease resistance of an entry is evaluated during each year, in which it is included in the various yield trials.
- Quality Tests Quality tests are conducted to determine the suitability of an entry for the various uses of its produce. The quality of a crop is not a simple character and is often not easy to determine. Therefore, several different tests have to be conducted, for which sophisticated equipments may be needed for speedy and reliable results. Quality tests are ordinarily carried out on all the entries included in URT/CVT.
Outstanding entries are identified for prerelease multiplication at the annual workshops of the coordinated research projects on the respective crops. The proposals for identification in some crops are considered ia an open forum by the participants in the workshop, while in some other crops e.g. wheat, they are examined by an Identification Subcommittee, which ordinarily has the following composition: (1) Deputy-Director General (Crop Sciences), ICAR, New Delhi (Chairman); (2) the project Director/Project Coordinator of the concerned coordinated project; (3) Principle Investigators for the different disciplines e.g. Agronomy, Pathology, Quality, Entomology, Physiology etc. of the concerned coordinated project; and (4) up to 5-6 persons actively involved in the project. Proposals for identification of entries are prepared by the respective breeders, who had developed the concerned entries. They are prepared according to the prescribed performa and include performance of entries in URT for at least two years, data from pathological, entomological, quality tests etc. and those from Agronomic trials.
An entry considered suitable for release as a variety by the concerned workshop is said to have been identified for prerelease multiplication or simply as identified. The criteria for identification of entries vary considerably from one crop to other. However, an entry immune to disease but significantly inferior to the check in yield is not identified since yield is the most important breeding objectives in any crop. In addition, one of the essential requirements for identification of a strain is that the breeder must be able to spare 10 Q seed of the proposed strain. This seed is supplied to State Farms Corporation of India (SFCI) for prerelease multiplication as well as for distribution for Adoptive and Minikit Trials.
Release of a Variety by the Central Subcommittee on Crop Standards and Release of Varieties
After identification, a variety is tested for at least one year in Adoptive Research Trials. During this period, disease tests and quality tests are also conducted. Based on the data from Adoptive Trials and disease and quality tests, the breeder who had developed the concerned entry submits a proposal for its release as a new variety for consideration by the Central Subcommittee on Crop Standards and Release of Varieties. After a variety has been released for a zone, notifies the concerned authorities of the states within that zone for seed multiplication and distribution of the variety; this is known as notification of the variety. A variety must be notified by the Ministry of Agriculture, Government of India, before its seed can be certified. In addition to the Central Subcommittee on Crop Standards and Release of Varieties, each state has its own variety release committee. The State Variety Release Committee usually requires a separate set of trials conducted at the Regional Research Stations of the state, in addition to the data from coordinated Multilocation trials.
Multiplication
When an entry is identified by the workshop of the concerned project, the breeder begins seed multiplication of that entry in the following crop season. The seed produced by the breeder after an entry is identified but before it is released as a variety is termed as the stock seed. The stock seed itself is known as breeder seed once the identified entry is released as a variety and notified. In the crop season following the release of a variety, certified seed of the variety is produced. Thus, the farmer is able to obtain certified seed of a newly released variety for commercial cultivation only in the third crop season following the release and notification of the variety.
References:
1. Singh, B. D. (2015). Plant breeding principles and methods. Tenth Revised Edition, Kalyani Publishers, New Delhi.
2. Singh, P. (2010). Essentials of plant breeding. Fourth Revised Edition, Kalyani Publishers, New Delhi.
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