DRRH6

Background:

 Rice is a critical food crop for India’s population and economy, but cultivation faces persistent challenges including delayed monsoon onset and terminal droughts/floods, labor and input shortages, need for short-duration varieties in intensive cropping systems. While early maturing inbred varieties offer timely harvesting, they generally lack hybrid vigor. Moreover, there is a limited availability of early-duration rice hybrids (<120 days) that combine high yield, broad adaptability, market-preferred grain quality, and the feasibility of large-scale seed production using cytoplasmic male sterile (CMS) lines with good outcrossing ability.

To address these challenges, DRRH6 an early duration hybrid (<120 days), developed using:

• IR68897A as the CMS line, based on the Wild Abortive (WA) cytoplasmic male sterility system. This CMS line exhibits excellent outcrossing ability, making seed production highly efficient.
• RPHR 6840-46 as the restorer line, an indica/tropical japonica-derived line developed through inter-subspecific hybridization, it confers broader adaptability and stress tolerance.

Importantly, the same CMS line (IR68897A) was used earlier to develop DRRH-2, a hybrid released in 2005 that became highly popular and was licensed to over 15 private seed companies. This hybrid (DRRH6) may help in replacing DRRH 2 which has been developed 20 years ago.

Targeted ecologies such as irrigated areas of eastern India (Bihar and Odisha) and parts of Uttar Pradesh. Ideal for rice–wheat, rice–pulse, multiple cropping systems. Meet the current demands of farmers operating under short season windows and resource constraints.

 Technology Details:

DRRH6 effectively addresses the key challenges in Indian rice cultivation, such as the demand for early maturity, high yield, blast resistance, and compatibility with intensive cropping systems. As an early-duration hybrid (<120 days), it offers a balanced solution combining superior performance, stress tolerance, and wide adaptability with efficient seed production potential. This innovation bridges the gap left by conventional early-maturing inbred varieties, which often lack hybrid vigor and yield stability. DRRH6 is both agronomically efficient and commercially viable, making it a suitable candidate for large-scale adoption, especially in eastern India.

Unique Features of DRRH6

Official Release and Area Suitability:

DRRH6 is notified and released by the Central Sub-Committee on Crop Standards, Notification and Release of Varieties (CSCCSN&RV) for commercial cultivation in Bihar, Odisha, and Uttar Pradesh. It is best suited for irrigated transplanted conditions, with medium slender grain type, preferred in local markets.

Genetic Background:

Developed from a cross between IR68897A (CMS line) and RP6380-46 (restorer line). The male parent is derived from an indica × tropical japonica breeding programme, which imparts improved adaptability and resilience.

Performance in National Trials:

DRRH6 was rigorously evaluated under the All India Coordinated Research Project on Rice (AICRPR) in the Early Transplanted (ETP) trials during wet seasons of 2019, 2022, and 2023 across 54 locations (15 in 2019, 21 in 2022, and 18 in 2023).

In Zone III (Eastern India), DRRH6 consistently outperformed national and local checks. Its average grain yield was 5850 kg/ha, which is:

• 18% higher than National Hybrid Check (NHC)
• 34% higher than National Varietal Check (NVC)
• 30% higher than Zonal Check (ZC)
• 12% higher than Local Check (LC)

Disease and Pest Resistance:

DRRH6 demonstrated moderate resistance under natural field conditions to major diseases such as: Neck blast, Leaf blast, Bacterial Leaf Blight, Sheath Blight, False Smut, Brown Spot, and Rice Tungro Disease (RTD). It also showed resistance to major insect pests, including stem borer and leaf folder.

Grain and Milling Quality:

• Hulling: 80.2%
• Milling: 69.9%
• Head Rice Recovery (HRR): 58.9%
• Amylose Content: 26.31%
• Gel Consistency: 41.3 mm
• Alkali Spreading Value: 4.0
• Grain Type: Medium Slender
• Grain Dimensions: Kernel Length – 6.12 mm, Kernel Breadth – 2.02 mm, L/B Ratio – 3.02 (Medium Slender)

Exceptional Yield at Specific Locations:

At individual trial sites, grain yields ranged between 7800 and 9400 kg/ha, highlighting the hybrid’s potential under favorable conditions.

In summary, DRRH6 combines high yield, early maturity, moderate disease resistance, and market-preferred grain quality, making it an ideal hybrid for intensifying rice production in eastern India.