Plant Breeding & Genetics
The main emphasis of Rice breeding is on the development of Basmati and non-Basmati high yielding varieties of rice with wider adaptability possessing desirable quality characteristics and resistant / tolerant to insect / pest and diseases. Development of rice hybrids. Development of short duration varieties. Pre-basic and basic seed production of approved varieties. Adaptability study of exotic material received from IRRI etc.
This section is conducting farmers participatory development, refinement and disseminate the production technologies for both medium and fine grain varieties. Besides efficiency and suitability for pre and post emergence herbicides. Studies on cropping pattern, draught tolerance and planting geometry are also being carried out.
Screening of rice varieties / lines against salinity and to conduct research trial to determine the effects of application of macro nutrients (dose, method and time of application and residual effects) on yield, yield components and quality of new rice lines / varieties.
The section of entomology conduct research work on the appropriate dose and time of pesticide application for the control of rice stem borer, rice leaffolder and white backed plant hopper. Furthermore, population study of different insect pests under field conditions.
Plant pathology section is involved in the identification o genetic against lea blight, blast, bakanae and stem rot through screening and utilization of resistant sources in the breeding programme. It also conduct research on the chemical and cultural disease management for devising integrated disease management of rice disease.
To screen breeding material for desirable quality characteristics. To evaluate effect of different level and time of input application on grain quality. To study the effect of various cultural practices and post harvest handling on grain quality.
STRATEGIES FOR INCREASING YIELD ON SUSTAINABLE BASIS
1. Conventional hybridization:
Modern Indica cultivars especially Basmati rice have a narrow genetic base for yield and other characters of interest. Rice gene pool are widened through hybridization of crop varieties with wild species, weedy rices as well as intersubspecific crosses. There is a need to collect the wild relatives of rice to transfer useful genes i.e., resistance to blast and bacterial leaf blight into locally developed rice varieties.
2. Ideotype breeding
(modification of plant architecture i.e New Plant Type (NPT) with the characteristics of:
- Low tillering (9-10 tillers for transplanted crop)
- No unproductive tillers
- 200-250 grains per panicle
- Dark green, thick and erect leaves
- Vigorous and deep root system
- Three NPT lines have been released in China and two in Indonesia.
NPT characteristics should be incorporated in Basmati and coarse rice varieties to break the yield barrier of these varieties. NTP in basmati background should also be developed.
Marker assisted selection (MAS) has also been employed from moving genes from pyramided lines into NPT as well as improved varieties in the world.
3. Development of Super rice hybrids.
- Rice hybrid with yield advantage of 10-15% over the best inbred varieties were introduced in China in 1970s and planted over 50% of rice land of that country. China has even developed super rice hybrids with the yield potential of 19 t /ha. Whereas the yield potential of the locally developed and imported rice hybrids have the yield potential of 12 t/ha.
- Super rice hybrids should be developed in three and two lines system having excellent grain quality.
4. Development of Bacterial leaf blight resistant /tolerant basmati rice varieties
- Super Basmati and Basmati 2000 are very popular among farmers, millers, exporters and consumers for high yield, better cooking and qualities. Super Basmati covers about 70 percent rice area in the Punjab. Unfortunately, both of these varieties are susceptible to Bacterial leaf blight (a major threat to basmati rice production).
- Marker-Assisted Breeding is done through out the world for the incorporation of resistant genes against blast and BLB to save time and money.
- Marker assisted selection (MAS) is being used for pyramiding genes i.e., Xa 4, Xa13, & Xa21 into a single breeding line for resistance to BLB. India has developed Pusa 1460 (improved Pusa Basmati 1) BLB resistant variety having genes xa13 and Xa21 through DNA marker-assisted pyramiding of BLB genes.
- BLB resistant basmati varieties should be developed using both conventional and molecular techniques to save time and money.
5. Development of Bt rice.
- Major targets of rice improvement through genetic engineering are diseases and insects.
- A major target of Bt deployment in transgenic rice is the yellow stem borer. Bt rice has been tested under field conditions and has excellent resistance to diverse populations of yellow stem borer.
- Besides Bt genes other genes for insect resistance such as those for proteinase inhibiter, α-amylase inhibitor (natural plant defense system) and lectins are also receiving attention.
6. Development of Aerobic rice
- One of the biggest constraints in maintaining rice productivity growth is a looming shortage of water. Per capita water availability has decreased from 5660 m3(1960) to 1400 m3(2006)
- We can overcome this water shortage by the developing drought tolerant rice varieties and / or Improving water use efficiency in rice crop
- Studying the minimum water requirement for rice i.e. only at critical stages without reducing yield
- There are two principal rice technologies being developed to improve water use efficiency. In the alternate wetting and drying (AWD) system, conventionally transplanted lowland) rice fields are allowed to drain between irrigations, retaining a water layer only during sensitive crop stages like flowering. IRRI-developed guidelines on AWD can reduce water use by 15–20%, with little yield loss.
- The aerobic production system is a more radical approach that reduces water use by up to 50%. The governments in South Asia have made development of water-saving, drought tolerant varieties a high research priority. The Pakistan Agricultural Research Council (PARC) identified the development of water-efficient rice cultivars as one of five major research thrusts for collaboration between Pakistan and IRRI.
7. Value addition
- Rice grain does not contain beta carotine, the precursor of vitamin A. Therefore children who derive most of their calories from rice suffer from vitamin-A deficiency.
- It is anticipated that varieties with beta carotine called Golden rice is going to be released soon. Golden rice will help reduce child mortality (100 million).
- Two billion of the world’s population suffers from iron (Fe) deficiency. High iron content ( 2 times more) variety has been released by conventional breeding and through genetic engineering in the world.
- Some very important by-products such edible oil and glucose can also be obtained from rice varieties in future.
- Pakistan has potent ional to produce up to 0.18 million ton of rice bran edible oil of worth rupees up to 3600 million
- There is need to explore the high quality edible oil from rice bran for commercial use which is at present being fed to the animal or urt as fuel, which is most prestigious and highly favorable to cholesterol and heart patient
- Genes for beta carotene and high iron contents should be incorporated in to basmati varieties besides the work on quantification of aroma in basmati rice varieties.
8. Improving soil health
- Presently our soils are very low in Organic Matter on an average 0.5%
- Organic Matter level is consistently decreasing due to high cropping intensity and burning the crop residue
- incorporation of rice straw will increase the Organic Matter
- Organic Matter increase the N and Carbon of soil, micro & macro nutrienrs along with improving the soil health.
- Organic matter can be added through Green Manu ring and crop residue incorporation
- We need to explore how many grams of soil organic Carbon and N per Kg of Rice straw incorporated in the soil
- How much yield will increase for rice-rice & for rice-wheat system through straw incorporation
- How much N fertilizer application will reduce by straw management
9. Direct seeding
- Advantages of direct seeding: save labour; Save water up to 30%; More economical than transplanting; overcome the low plant population, delayed and aged rice nursery transplanting
- But there is a weed problem in direct seeding. It is need to explore the weeds control, selection of suitable rice varieties for minimum water requirement without scarifying the yield and quality.