Role of Resistant Chilli Varieties in Mitigating Phytophthora Root Rot and Chilli Leaf Curl Virus

India is the global leader in the production, consumption, and export of dry chilli, a vital component of its spice industry. Chilli is one of the most important spices integral to Indian cuisine. With approximately 400 different types of chillies cultivated across the country, the economic significance of chillies was evident, contributing over 130 billion Indian rupees in the fiscal year 2020. However, recent challenges have emerged, posing significant threats to chilli crop production and thereby impacting the nation's economy. The Indian Institute of Horticulture Research (IIHR) has developed three hybrid chilli varieties that exhibit resistance to several diseases including phytophthora root rot (PRR) and leaf curl virus (LCV).

Threats from Phytophthora Root Rot & Chilli Leaf Curl Virus

Phytophthora root rot (PRR) and Chilli leaf curl virus (ChLCV) are identified as major adversaries jeopardizing chilli cultivation. PRR, attributed to the fungal oomycete soil-borne pathogen Phytophthora capsici Leonian, is notorious for causing root rot, resulting in substantial yield losses. This destructive pathogen is estimated to inflict global losses amounting to approximately USD 100 million annually.

Concurrently, the spread of ChLCV, transmitted by whiteflies, has emerged as a devastating menace, particularly in the Indian subcontinent. Alarmingly, instances of nearly 100% yield loss have led to the withdrawal of chilli cultivation by farmers in certain regions of India.

Ineffectiveness of Chemical Control and Imperative of Host Plant Resistance

Chemical control measures against these pathogens have proven ineffective and have raised concerns regarding chemical residues, which can hinder export prospects. Consequently, there is a pressing need to explore alternative strategies, with the advocacy for host plant resistance emerging as the most promising approach.

Development of Resistant Varieties

In response to these challenges, significant strides have been made in breeding resistant chilli varieties. Through a combination of phenotypic selection and marker-assisted selection, Cytoplasmic Genic Male Sterility (CGMS) lines have been developed. These lines were subsequently utilized to create F1 hybrids, employing male parents resistant to ChLCV.

Twenty CGMS-based F1 hybrids, alongside commercial check varieties, underwent rigorous evaluation for resistance against Phytophthora root rot. The assessment involved artificial challenge inoculation as well as testing in infected plots. Encouragingly, certain varieties, notably LCVH 24 (Arka Nihira), LCVH 29 (Arka Dhriti), and LCVH 30 (Arka Gagan), exhibited consistent resistance to both Phytophthora root rot and ChLCV.

Spotlight on Arka Nihira and Arka Dhriti

Among the resilient varieties, Arka Nihira and Arka Dhriti stand out for their commendable attributes and adaptability to specific market segments.

1. Arka Nihira:

A CGMS-based high-yielding chilli F1 hybrid, tailored for the dual thick market segment.

Noteworthy features include:

• Suitable for dual thick market segment

• High yield (fresh 12-14 and dry 3-3.5 t/ acre)

• Fruit solitary pendant

• Fruit length 9-10cm and width-1.2-1.5cm

• Fruits dark green turns dark red (110-120 ASTA value) on maturity

• Medium pungent (35,000-40,000 SHU)

• Good dry recovery (~30%)

• Combined resistance to Phytophtora root rot and chilli leaf curl virus (ChLCV) Rai - isolate

2. Arka Dhriti:

A CGMS-based chilli F1 hybrid, catering to the dual medium market segment.

Key features encompass:

• Suitable for dual medium market segment

• High yield (fresh 12-14 and dry 3-3.5 t/ acre)

• Fruit solitary pendent

• Fruit length 7-8cm and width-1.0-1.2cm

• Fruits green turns dark red (80-90 ASTA value) on maturity

• Highly pungent (80,000-90,000 SHU)

• Good dry recovery (30-32%)

• Combined resistance to Phytophtora root rot and chilli leaf curl virus (ChLCV) Rai–isolate

The development and adoption of resistant chilli varieties such as Arka Nihira and Arka Dhriti signify a pivotal step towards mitigating the adverse impacts of Phytophthora root rot and ChLCV. This information is provided by Madhavi Reddy K., Principal Scientist, Division of Vegetable Crops, IIHR to Krishi Jagran. These efforts not only safeguard the livelihoods of chilli farmers but also bolster India's position as a global leader in dry chilli production and export.