🧬 Barley — Breeding for Yield and Malting Quality

This lesson connects barley botany with trait-specific breeding goals for yield, malt industry standards, and major disease resistance.

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Origin and Botany

Barley (Hordeum vulgare L., 2n = 2x = 14) belongs to the family Poaceae and is the fourth most important cereal globally after maize, rice, and wheat. The primary centre of origin is Ethiopia and South-East Asia (Vavilov). Barley is classified into two-row (H. vulgare var. distichon) and six-row (H. vulgare var. hexastichon) types based on the fertility of lateral florets. In two-row barley, only the central floret is fertile, producing plump, uniform grains preferred for malting. In six-row barley, all three florets at each node are fertile, resulting in higher grain number but variable grain size. Barley may also be classified as hulled or hull-less (naked) types. It is a diploid, predominantly self-pollinated crop with less than 1% outcrossing.

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Breeding Objectives

The major breeding objectives include yield improvement through development of semi-dwarf, lodging-resistant varieties with high tillering capacity. Malting quality is a premium breeding target, especially for the brewing industry. Key malting quality traits include high extract yield (>80%), adequate diastatic power (enzymatic activity), low protein content (9-12%), high starch content, plump and uniform grain size, low beta-glucan content, and husk adherence for proper filtration. Feed barley breeding focuses on high protein content, high lysine (as in Hiproly mutant), and hull-less types for improved digestibility. Disease resistance breeding targets stripe rust (Puccinia striiformis f. sp. hordei), covered smut (Ustilago hordei), loose smut (U. nuda), powdery mildew (Blumeria graminis), and net blotch (Pyrenophora teres). Tolerance to terminal heat stress, salinity, and drought are also important objectives for Indian conditions.

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Breeding Methods and Achievements

Being self-pollinated, barley is improved through pure line selection, pedigree method, backcross method, and mutation breeding. Hybridization is performed using the conventional emasculation and pollination technique or the hot water emasculation method. Mutation breeding has been particularly successful in barley, producing varieties like Jyoti (from NP 113 through gamma irradiation). Notable Indian varieties include RD 2035, RD 2552 (dual-purpose), BH 393 (six-row feed type), DWRB 73 (malt barley), and RD 2899 (rainfed conditions). The ICAR-Indian Institute of Wheat and Barley Research (IIWBR), Karnal, coordinates the All India Coordinated Research Project on Barley. Modern breeding incorporates doubled haploid (DH) technology using the bulbosum technique or anther culture for rapid fixation of homozygous lines. Molecular markers linked to malting quality QTLs are increasingly being deployed for marker-assisted selection.

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Summary Cheat Sheet

Quick Recall Points

• Barley is diploid (2n=14) and mainly self-pollinated.
• Two-row types are preferred for uniform malting quality.
• Malting targets include high extract, low beta-glucan, and suitable protein range.

Exam Traps

• Six-row barley can produce more grains but does not automatically imply better malt quality.
• Feed barley and malt barley breeding priorities are different.

References

2 sources • [1] [2]

[1]

Barley: Production, Improvement, and Uses

Book

[2]

ICAR-IIWBR barley programme

Official