🧬 Field Pea — Breeding for Yield and Disease Resistance

This lesson links classical pea genetics with present-day breeding objectives for disease resistance, architecture, and stable yield under rabi conditions.

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Origin and Botany

Field pea (Pisum sativum L., 2n = 2x = 14) belongs to the family Fabaceae and holds historical significance as the experimental organism used by Gregor Mendel for establishing the laws of heredity. The primary centre of origin is the Near East and Mediterranean region, with Ethiopia and Central Asia as secondary centres. India is a major producer, with cultivation concentrated in Uttar Pradesh, Madhya Pradesh, Rajasthan, and Bihar. Field pea is a cool-season legume, predominantly self-pollinated with less than 1% natural outcrossing. It is grown as a rabi season crop and serves as an important source of vegetable protein (20-25%), dietary fibre, and essential amino acids.

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Breeding Objectives

The major breeding objectives include yield improvement through development of plant types with increased pod number, seeds per pod, and 100-seed weight. Powdery mildew resistance is the most important breeding target, as the disease caused by Erysiphe pisi can cause yield losses exceeding 50%. Resistance to powdery mildew is governed by the recessive gene er1 (and its alleles er1 and er2), which provides complete resistance. Rust resistance (Uromyces viciae-fabae), Fusarium wilt (Fusarium oxysporum f. sp. pisi), and Ascochyta blight resistance are also targeted. Development of semi-leafless types (with tendrils replacing leaflets, controlled by the af gene) is a key architectural improvement, as these types are lodging-resistant, allow better light penetration, air circulation, and are suitable for mechanical harvesting. Early maturity for escaping terminal heat and fitting into multiple cropping systems is important. Tolerance to pod shattering for harvest stability and frost tolerance are additional objectives.

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Breeding Methods and Achievements

Being a self-pollinated crop, field pea is improved through pedigree method, bulk method, single seed descent, and backcross breeding. Hybridization involves emasculation of the keel petal to remove immature anthers before pollination. The small flower size makes crossing work technically demanding. Mutation breeding has contributed to development of early-maturing and semi-dwarf types. Key varieties developed in India include HUDP 15 (semi-leafless, powdery mildew resistant), Pant P 42, Rachna, IPFD 10-12, and Aman (early maturing). DDR (Pusa), Pantnagar, and IIPR Kanpur are major centres for field pea research. The introgression of er1 gene through backcross breeding has been highly successful in developing powdery mildew resistant cultivars. Molecular markers linked to the er1 locus (ScOPD10 and others) facilitate marker-assisted selection. Modern genomic tools including SNP arrays and genome-wide association studies (GWAS) are being deployed to identify novel QTLs for yield and stress tolerance.

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Summary Cheat Sheet

Quick Recall Points

• Field pea is 2n=14 and mostly self-pollinated.
• Powdery mildew resistance commonly uses er1-based introgression.
• Semi-leafless (af) plant type improves standability and mechanization.

Exam Traps

• Do not treat all mildew resistance genes as equivalent in durability.
• Semi-leafless architecture improves management but still needs trait balance for yield.

References

2 sources • [1] [2]

[1]

Pea Improvement and Production

Book

[2]

ICAR-IIPR pulse breeding resources

Official