Unit II
Commercial Plant Breeding & Seed Industry
Contents
Genetic purity test of commercial hybrids. Advances in hybrid seed production of maize, rice, sorghum, pearl millet, castor, sunflower, cotton pigeon pea, Brassica etc.
Genetic purity test of commercial hybrids
Genetic purity testing is a crucial step in the production and marketing of commercial hybrids. It ensures that the hybrid seeds being sold to farmers are true to their genetic composition and free from any contaminating or off-type materials. The genetic purity test helps maintain the quality and performance of the hybrid, which directly impacts the yield and uniformity of the crop for the farmers.
Methods of Genetic Purity Testing:
- Visual Inspection: This is a preliminary assessment where trained personnel visually inspect the plants for any morphological differences. Off-type plants are identified based on their appearance and removed from the seed lot.
- Molecular Markers: Molecular marker techniques are advanced methods used to analyze the genetic composition of the seed samples. These techniques are highly accurate and can detect even small variations in the DNA of the seeds.
- Cytoplasmic Male Sterility (CMS) Test: In some hybrids, male sterility is an essential trait, and CMS is used. The CMS test confirms the presence of the CMS gene in the hybrid seed, ensuring its male-sterile characteristic.
- Field Testing: Field trials are conducted to evaluate the performance and characteristics of the hybrid in comparison to known standards. Any deviation from the expected traits could indicate impurity.
Steps in Genetic Purity Testing:
- Sampling: A representative sample is collected from the seed lot. The sample size must be adequate to ensure reliable results.
- Isolation Plot: A small isolation plot is established where the sample seeds are sown separately. This plot should be far enough from other plots or fields to prevent contamination.
- Planting: The seeds are sown in the isolation plot, and the plants are allowed to grow and produce seeds.
- Visual Inspection: The plants in the isolation plot are visually inspected to identify any off-types or variations.
- Harvesting: The seeds from the isolation plot are harvested separately from each plant to maintain their genetic identity.
- Laboratory Testing: The harvested seeds are sent to the laboratory for molecular marker analysis and other tests if required.
Importance of Genetic Purity Testing:
- Assurance of Quality: Genetic purity testing ensures that farmers receive high-quality hybrid seeds with the promised traits and performance.
- Farmers' Confidence: Certified genetic purity instills confidence in farmers, encouraging them to adopt modern hybrid varieties and invest in improved agricultural practices.
- Brand Reputation: Seed companies build their reputation on providing genetically pure and reliable hybrid seeds, enhancing their credibility in the market.
- Sustainable Agriculture: Maintaining genetic purity supports sustainable agriculture practices by delivering seeds that perform as expected, contributing to increased yield and overall productivity.
Advances in Hybrid Seed Production of Various Crops:
Hybrid seed production has revolutionized modern agriculture, providing farmers with high-yielding and uniform crops. Advancements in hybrid seed production have significantly contributed to increased productivity, better pest resistance, and improved overall crop performance. Let's explore some of the advances in hybrid seed production for specific crops:
1. Maize:
- Advances in Breeding Techniques: Marker-assisted breeding and genomic selection have accelerated the development of superior maize hybrids with specific traits like drought tolerance, disease resistance, and improved nutritional content.
- Double Haploid Technology: This technique allows for the rapid development of pure breeding lines, streamlining the process of creating new hybrids.
2. Rice:
- Two-Line Hybrid System: The two-line hybrid system has been widely adopted for rice hybrid seed production, ensuring genetic purity and maintaining the male-sterile trait efficiently.
- Hybrid Varieties with Submergence Tolerance: Breeding efforts have led to the development of rice hybrids with enhanced tolerance to submergence, benefiting farmers in flood-prone regions.
3. Sorghum and Pearl Millet:
- Cytoplasmic Male Sterility (CMS) System: CMS-based hybrid seed production has become prevalent in sorghum and pearl millet, ensuring high seed purity and yield potential.
4. Castor:
- Inbred Line Development: Efforts to develop inbred lines with stable genetic traits have led to the production of high-yielding and disease-resistant hybrid castor varieties.
5. Sunflower:
- Genetic Engineering: Genetic modification has been used to introduce traits such as herbicide tolerance and enhanced oil content in sunflower hybrids.
6. Cotton:
- Bt Cotton Hybrids: The incorporation of Bacillus thuringiensis (Bt) genes into cotton hybrids has provided effective resistance against major insect pests, reducing the need for chemical insecticides.
7. Pigeon Pea:
- Hybrid Pigeon Pea Varieties: Advances in hybrid pigeon pea production have led to improved yields, pest resistance, and adaptability to diverse agro-climatic conditions.
8. Brassica (Mustard):
- CMS-Based Hybrids: Brassica hybrids produced through cytoplasmic male sterility (CMS) systems have shown improved yield potential and uniformity.
Benefits of Hybrid Seed Production Advances:
- Increased Yield: Advanced hybrid varieties have demonstrated higher yield potential, meeting the increasing demand for food and raw materials.
- Pest and Disease Resistance: Hybrid seeds with built-in resistance to pests and diseases reduce the need for chemical pesticides, promoting sustainable agriculture.
- Better Adaptability: Modern hybrid varieties are bred to be adaptable to varying climatic conditions, ensuring stable production in diverse environments.
- Quality Improvement: Advances in hybrid seed production have enhanced crop quality, such as improved nutritional content, oil content, and fibre strength.
📚 For comprehensive notes on other chapters of the subject, please visit the website Agricorn - Commercial Plant Breeding & Seed Industry