Elucidating Traditional Rice Varieties for Consilient Biotic and Abiotic Stress Management under Changing Climate with Landscape-Level Rice Biodiversity

Abstract

Rice is grown under diverse agro-climatic conditions and crop management regimes across the globe. Emerging climatic-vulnerabilities and the mismatched farm practices are becoming major challenges for poor or declining rice productivity in potential rice growing regions, especially South Asia. In the biodiversity-rich landscapes of South Asia, many traditional rice varieties (TRVs) are known to exhibit resilience to climate change and climate adaptation besides their therapeutic benefits. Hence, a random sample survey of farmers (n = 320), alongwith secondary data collection from non-governmental organizations/farmers’ organizations/farmers, led to documentation of the information on TRVs’ biodiversity in South Asia. The current study (2015–2019) explored and documented ~164 TRVs which may enhance the resilience to climatic-risks with improved yields besides their unique therapeutic benefits. A large number of TRVs have still not been registered by scientific organizations due to poor awareness by the farmers and community organizations. Hence, it is urgently needed to document, evaluate and harness the desired traits of these TRVs for ecological, economic, nutritional and health benefits. This study suggests taking greater cognizance of TRVs for their conservation, need-based crop improvement, and cultivation in the niche-areas owing to their importance in climate-resilient agriculture for overall sustainable rice farming in South Asia so as to achieve the UN’s Sustainable Development Goals.

1. Introduction

Rice belongs to the genus Oryza, under the family Gramineae. Out of the 27 species of the genus Oryza, 25 species are wild and only 2 are cultivated—Oryza sativa and Oryza glaberrina (mainly in Africa)—as a staple cereal food grain for more than half of the global population [1]. Rice is grown under diverse climatic and soil conditions. Rice is the largest consumer of irrigated water and is responsible for enormous greenhouse gas (GHG) emissions, particularly methane and nitrous oxide, that cause global warming. The emerging climate change impacts, including the depletion of the water table and shrinking water supplies, are responsible for a severe reduction in rice production [2]. Rice is planted on about one-tenth of the Earth’s arable land in ~114 countries across the globe, occupying ~150 m ha. Although India is the second largest producer (113 mt) next to China with 44 mha area under rice, its average yield (~2.6 t/ha) is far below both that of China (>6 t/ha) and the global average of ~4 t/ha [3]. Further, climate-impacted weather patterns resulting in more persistent droughts, floods and cyclones, followed by a decline in soil biodiversity, salinization, water-logging, groundwater depletion, micronutrient deficiencies (Zinc and Sulphur), emerging pests and diseases, excessive use of fertilizers and pesticides, etc. have led to a decline in productivity in rice-producing regions [4].

At the same time, India is a rice growing country and constitutes an important center of rice cultivation. Half a century ago, it was home to more than 100,000 rice varieties with a rich varietal diversity. These traditional rice varieties (TRVs) perform on a par with or better than the modern varieties under traditional management and care with a wide range of morphological and physiological characteristics, particularly in the climate change affected areas, taking from 60 to over 200 days to attain maturity [5]. Additionally, the TRVs represent significant genetic pools with valuable traits of unique genetics, grain length, diversity in taste, nutrition, pest-resistance, color, thickness, stickiness, aroma, export potential, medicinal properties and other characteristics [6]. The TRVs also play a very important role in climate-resilience in direct-sown conditions, aerobic conditions, irrigated system of rice intensification (SRI) and alternative cropping systems such as integrated farming systems (IFS) for increased rice production [7]. The adoption of TRVs with modern practices may give encouraging results with respect to food and nutrition security and climate resilience; and hence, TRVs are more likely to address the UN’s Sustainable Development Goals (SDGs). Thus, there is an urgent need to encourage farmers in climate-vulnerable rice ecosystems to cultivate indigenous rice cultivars to assist with the in situ conservation of the rice genepool in India in particular and collateral agroecologies across the globe in general. TRVs present a promising opportunity for small and marginal farmers practicing traditional, low-input intensive farming and organic farming to optimize their production levels with fewer costs [8,9]. The TRVs also play an important role in Siddha medicine, which originates from Tamil Nadu, India. In Siddha medicine, many TRVs are used to treat joint diseases, skin diseases, liver problems, and urinary tract infections [10].

High yielding semi-dwarf rice varieties have changed the scenario of pest occurrence with high incidence of several pests such as brown plant hoppers and stem borers and diseases such as rice blast, bacterial blight and sheath rot, etc., due to a high intake of N-fertilizers, insecticides and other agrochemicals, etc. On the other hand, low-input intensive traditional rice farming comprising of judicious use of locally available nutrient sources, crop residue management and crop diversification is known to sustain traditional rice productivity in addition to conserving natural resources and rice biodiversity [5,7]. Hence, traditional rice produce holds great potential for producing more rice while incurring lower costs and using less water, with enhanced nutrient-use efficiency and reduced GHG emissions in rice-based production systems that would in turn help to mitigate the effects of climate change [11]. Farmers in rural parts of the country still retain TRVs in their farming systems. Hence, it is high time to improve farmers’ awareness and knowledge about local landraces for their in situ conservation and seed multiplication for climate-resilience. It may help in the dissemination of important TRVs for community-based genetic resource conservation. It may also attract the attention of agricultural scientists, farmers and other stakeholders for crop improvement and the dissemination of the indigenous rice genepool for discovering more information about TRVs for biotic and abiotic stress management under a changing climate with landscape-level rice biodiversity. With this backdrop, the current exploratory study was carried-out to explore and document the existing TRVs in various agro-ecological landscapes of the Western Ghats, the Eastern Coastal Region, Central India and the North-Eastern Hill Region of India [12].

2. Materials and Methods

2.1. Selection of Rice Biodiversity Rich Landscapes

Documentation and assessment of traditional rice varieties (TRVs) is very important to elucidate their role in biotic and abiotic stress management under a changing climate, so as to upscale and out-scale the TRVs for imparting climate-resilience to farming and to conserve the rice genepool. Under this study, traditional rice farmers of 4 landscapes viz. the Western-Ghats Region (WGR), East-Coastal Region (ECR), Central India Region (CIR) and North-Eastern Hill Region (NEHR) of India were selected purposefully owing to their landscape-based genetic diversity. As per Koppen’s climate classification system, the study areas of WGR, ECR, CIR and NEHR fall under the Tropical monsoon (Am), Tropical savanna climate (Aw/As), Tropical savanna climate (Aw/As), and Humid subtropical climate (Cwa), respectively. Among these four regions, the field survey was conducted in two locations viz. WGR and ECR. Secondary data were collected from and used for the remaining two locations viz. CIR and NEHR of India. The ex-post facto research design was used for this study [13]. These selected regions have a predominance of small and marginal farmers who generally practice subsistence farming, with the predominance of rice-based production systems.

2.2. Selection of Study Areas–Districts/Blocks/Villages

For the field survey, four Indian states, viz. Maharashtra, Karnataka, Kerala and Tamil Nadu, were selected purposefully, where the WGR and ECR regions exist with specific climate-resilient indigenous rice production systems Based on secondary information and pilot studies, we further purposefully selected six districts among the selected states viz. tribal dominated Palghar district of Maharashtra, Shivamoga district of Karnataka, Wayanad district of Kerala and the Thanjavur, Thiruvarur and Nagapattinam districts of Tamil Nadu, where most farms are run by smallholders who use traditional rice cultivation practices, which are mostly followed for their own consumption rather than for the production of a marketable surplus. From these six selected districts, eight community development blocks (CBD—the smallest rural administrative unit in India) were purposefully chosen. Two CBDs, Jawhar and Vikramgad, from Palghar district; one CBD each in Shivamoga district (Thirthahalli), Wayanad (Sulthan-Bathery),Thanjavur (Pattukottai), Thiruvarur (Thiruthuraipoondi); and two CBDs, Vedaranniyam and Thalainayar, from Nagapattinam district were purposefully selected because a large number of farmers in these CBDs are cultivating TRVs to cope with the changing climate while conserving the rice genepool. Further, 4 villages were randomly selected from each selected CBD of these 6 selected districts in 4 states of the WGR and ECR (

Table 1. Selection of study areas–districts/CBDs/villages in the Western-Ghats Region and East-Coastal Region of India.

Selected States	Selected Districts/CBDs/Villages
	District	CBDs	Selected Villages
Maharashtra	Palghar	Jawhar	Radhanagari, Chowk, Daskod, Kogade
		Vikramgad	Balapur, Dadade, Sakhare, Vedhe
Karnataka	Shivamoga	Thirthahalli	Basavani, Changaru, Hanasa, Horani
Kerala	Wayanad	Sulthan-Bathery	Nenmeni, Ambalavayal, Cheeral, Nadavayal
Tamil Nadu	Thanjavur,	Pattukottai	Enathi, Kasangadu, Sembalur, Vattakudi
	Thiruvarur	Thiruthuraipoondi	Adirangam, Edaiyur, Panaiyur, Kunnalur
	Nagapattinam	Vedaranniyam	Chettipulam, Karuppampulam, Chettipulam, Pannal
		Thalainayar	Vellapallam, Neermulai, Thirividaimaruthur, Manakkudi

).

From each selected village, 10 farmers were selected randomly to collect the required data using semi-structured survey schedules during 2015–2019 [13]. Thus, the total sample size of the respondents for the study was three hundred and twenty (n = 320). The farmers were randomly selected with a predominance of subsistence-scale farmers mostly relying on TRVs (>80%) who primarily use TRVs for their own consumption. In general, the farmers in the study areas used to grow 4–15 TRVs per family depending upon the land-holding size, family preferences and the varietal peculiarity against biotic and biotic stresses. The climate resilience of TRVs was particularly documented in the current study. The term ‘climate resilience’ refers to the ability of the TRVs to anticipate, prepare for, and respond to hazardous events, trends, or disturbances related to the climate.

2.3. Data Collection and Documentation

A semi-structured survey schedule was prepared and the required data were acquired from respondent farmers through personal interviews, group discussions, and observations based on farmers’ field visits [13]. A multistage random sampling (MSRS) was used at three stages (at district→CBD→village level)[13].The field data relating to the TRVs viz. yield potential, climate-resilience (drought tolerance, pest and disease resistance/tolerance, etc.), nutritional value and medicinal value (if any), was collected from farmers in the study area. Finally, the farmers’ data w.r.t. to these attributes were field validated by the scientists of the IARI taskforce, and then the reliable and valid information was finally documented [5,12,13]. Similarly, the grain and straw yield data were recorded from the crop cutting experiments of the TRVs grown in the study area while utilizing the services of field functionaries of BAIF–Development Research Foundation and the farmers’ organizations of the study area. Wherever the collection of primary data was not possible, we collected secondary data. A matrix ranking of these TRVs was also calculated for these attributes in the study area. Focus group discussions (FGD) were conducted to identify and quantify the above attributes of TRVs [13]. A scientifically designed 6-point scale was also framed for assessing different attributes of the TRVs, as approved by the relevant experts of Indian Agricultural Research Institute (IARI), New Delhi, India. Hence, the farmers’ perceptions about these attributes were measured on a continuum of ‘6′ (best) to ‘1′ (worst) against a given parameter/peculiarity of the TRVs. The objective of calculating varietal scores on a 6-point scale was to measure the performance indices of these TRVs. FGD were held with selected farmers to generate weighted scores on their perceptions regarding resistance to diseases and pests and climate resilience, as well as the nutritional value and medicinal benefits of TRVs. Finally, the matrix ranking was calculated based on the number of TRVs chosen for ranking.

3. Results and Discussion

3.1. Traditional Rice Varieties of Western Ghats Region

The Western Ghats Region (WGR) is considered as a biodiversity hot-spot, especially for rice. It plays a very important role in the onset of the South West Monsoon and influences the country’s climate in several other ways. There is an urgent need to conserve rice biodiversity in this region. In rice, the high-yielding varieties (HYVs) introduced in the early 1960s have less significant impacts in the hilly terrains of the WGR due to soil health degradation as a consequence of the use of chemical fertilizers, poor water holding capacity, and outbreaks of insect-pests, diseases and weed infestations, etc. Hence, the HYVs underperform and give low yields, as the resource-poor tribal farmers in the WGR are unable to afford the recommended agricultural inputs, such as seeds, chemical fertilizers and pesticides. Most of the indigenous traditional rice varieties (TRVs) of the biodiversity-rich WGR have huge potential for water conservation, tolerance/resistance against drought/floods, pest and disease occurrence [13]. The direct-sown traditional rainfed rice varieties consume much lower amounts of water and give relatively better productivity with reduced methane emissions, improve carbon sequestration and increase the biomass production in the WGR ecosystem [5,14,15,16]. The tribal farmers traditionally used to cultivate over 300 TRVs, the majority of which are now rarely available for the farmers. Many of these TRVs have unique medicinal properties and are found to be more suitable for cultivation under the changing climate scenario in the region. Hence, there is an urgent need to conserve these indigenous genetic resources of rice.

3.1.1. Traditional Rice Varieties in Palgar District of Maharashtra in Western Ghats Region

The TRVs documented in

Table 2. Major characteristics and yield of traditional rice varieties in Palgar district of Maharashtra in Western Ghats Region of India (2019).

S. No.	Common/ Local Name	Characteristics and Benefits	Average Grain Yield (t/ha)	Average Straw Yield (t/ha)
(i) Brown planthopper-, stem borer-, case worm- and blast-resistant varieties
1	Kolpi (Early)	Fine grain with good cooking quality, good for fodder	3.34	6.45
2	Kolpi (Mid–late season)	Fine grain with good cooking quality, good for fodder, lodging-resistant	3.80	5.60
3	Kolpi (Late season)	Fine grain with good cooking quality, high quality fodder	4.55	6.30
(ii) Brown planthopper-, stem borer- and case worm-resistant varieties
4	Rajghudya	Long and slender grain. Good for biryani dishes and gruel preparation. Medicinal value; used for fodder and thatching and non-lodging purposes	4.50	7.00
5	Dangi White	Bold grain rice. Dry and upland cultivar. Good for making gruel and roti. It improves strength. Useful for fodder and thatching. Good yields in harsh environments	3.20	7.20
6	Dangi Red	Bold grain rice. Dry and upland cultivar. Good for making gruel and roti. Useful for lactating mothers. Used as quality fodder. Good yielder in harsh environments	3.50	7.40
7	Kasbai	Scented and fragrant landraces. Good for biryani, meals, fodder and thatching purposes	4.25	6.75
(iii) Stem borer- and case worm-resistant varieties
8	Dhaval	Scented rice and good for fodders	3.60	6.50
9	Dula 1	Scented and fragrant landraces. Good for making beaten rice, puffed rice. Good fodder and has medicinal uses	2.58	6.00
10	Dula 2	Scented and fragrant landraces and good fodder	3.20	6.20
11	Kali Kundai	Red rice and it improves strength	2.80	4.00
12	Malghudya	Good for making gruel (kanji) and good for fodder purposes. It improves strength	1.80	3.10
13	Mahadi (Mid–late season)	Red rice. Good for gruel (kanji) and roti purposes. Useful when recovering from fractures	-	-
14	Hari	Good yields in harsh environments.	-	-
(iv) Case worm- and brown planthopper-resistant varieties
15	Banglya	Scented and fragrant landrace. Good for biryani making. Good for fodder and thatching	4.60	7.50
16	Sagg (Jowhar)	Scented and fragrant rice. Good for beaten rice and puffed rice	2.40	3.80
17	Lalya	Good yields in harsh environments	4.40	6.70
(v) Stem borer-resistant varieties
18	Varangal (black)	Red colored scented rice	2.68	6.30
19	Varangal (awned)	Fragrant landrace	3.10	6.40
20	Masala	Scented rice and fragrant landrace	-	-
(vi) Case worm-resistant varieties
21	Sagg (Wada)	Scented and fragrant landraces; used for beaten rice and puffed rice	2.60	4.50
22	Kasvel	Scented rice, deep water cultivar	3.00	4.25
23	Tamkudai	Good yields in harsh environments	2.60	6.00
24	Dhundune	Scented rice and used for making Papad. Good yields in harsh environments	-	-
25	Juna Kolam	Resistance against lodging	3.80	4.80
26	Dev Bhat	Red rice, scented rice; deep water cultivar. Straw used for thatching	-	-
(vii) Brown planthopper-resistant variety
27	Kalbhat	Fragrant landrace	3.70	7.60
(viii) Other important rice varieties
28	Vakvel	Scented and fragrant landrace. Useful as fodder	3.10	6.30
29	Dodgi	Resistance against lodging	3.80	6.50
30	Pacheki	Good for thatching	3.98	6.20
31	LalyaSagg	Resistance against lodging	-	-
32	Kali Khadsi	Red rice. Provides strength	-	-
33	Kolam	Good fodder	-	-
34	Surti Kolam	Good for biryani, pilau, special dishes and fodder purposes
35	Bhat	Straw for thatching purposes. It has good market value
36	Gujrat Zini	Good yields in harsh environments	4.55	7.40
37	Zini (Early)	Good for fodder. It has good market value	2.82	4.85
38	Tulshya	Scented rice	-	-
38	Kavla	Good yields in harsh environments.	4.60	6.90
39	Masuri	Good for biryani, pilau and special dishes	-	-

revealed that most of the indigenous rice varieties of the Palgar district of Maharashtra in the WGR have tolerance to/resistance against pests and diseases in addition to tolerance against droughts/floods. An overview of the indigenous rice varieties with their yield levels (averaged), resistance to various pests/diseases as well as nutritional and medicinal value (if any), is given in Table 2.

A matrix ranking of these TRVs was also conducted in the study area (

Table 3. Matrix ranking for the traditional rice varieties in Palghar district of Maharashtra in WGR.

S. No.	Traditional Varieties	Resistance to Insect-Pest and Diseases	Climate Resilience (Drought and Flood Tolerance)	Suitability to Light Soil Conditions	Eating Quality	Yield and Market Price	Cost of Cultivation	Length of Straw for Thatching	Medicinal Value	Total Value	Rank
1	Kolpi (Early)	4	4	4	5	5	5	4	3	34	2
2	Kolpi (Mid late season)	4	4	3	4	5	5	4	3	32	4
3	Kolpi (Late season)	4	5	4	5	4	3	4	4	33	3
4	Rajghudya	5	4	5	6	5	4	6	5	40	1
5	Dangi White	3	3	3	5	4	3	5	4	30	6
6	Dangi Red	3	4	3	5	4	3	5	2	29	7
7	Kasbai	3	3	3	4	5	4	5	4	31	5
8	Banglya	3	4	4	3	2	2	5	4	27	9
9	Zini (Early)	4	3	3	4	2	2	3	2	23	13
10	Kalbhat	3	4	4	2	2	2	5	4	26	10
11	Vakvel	3	3	2	4	2	2	4	2	22	14
12	Dodgi	3	4	3	3	3	3	4	2	25	11
13	Pacheki	3	3	2	3	3	3	4	3	24	12
14	Dhaval	4	3	3	5	3	3	4	3	28	8

Note: 6 = Best; 1 = Worst. Ranking is calculated based on the number of items chosen for ranking. There are fourteen varieties. Hence, ranks varies from 1 to 14.

). Out of the 39 TRVs grown in the WGR, 14 varieties were ranked as being the most promising for the cultivation in the WGR as a result of their resilience to biotic and abiotic stresses, and their nutritional and medicinal as well as economic value (Table 3). Based on the overall matrix ranking score, these varieties were ranked in the following order: Rajghudya > Kolpi (Early) > Kolpi (Late) > Kolpi (Mid-late) > Kasbai > Banglya > Kalbhat > Dhaval > Dangi Red > Dangi White > Dodgi > Pacheki > Zini (Early) > Vakvel. The conservation and promotion of these indigenous rice varieties would definitely support the biodiversity of and sustain the livelihoods of the farmers in the WGR region. Further, the tribal rice farmers revealed that the four traditional varieties, viz. Kolpi (early), Dangi (White), Dangi (Red) and Rajghudya, have shown yield stability even under low external input-use, and under dry and rainfed farming conditions. These varieties possess climate-resilience in addition to resistance to pests and diseases. Apart from this, the traditional varieties viz. Dhaval, Kal Bhat, Kali Kudai, Kavla, Kolpi (Mid-late), Lalya, Malghudya, Tamkudai, Varangal (Black) have the ability to produce a large number of effective tillers leading to higher yields. Furthermore, the rice landraces viz. Banglya, Dodgi, Gujarat Zini, Kolam, Kolpi (ML), Kolpi (L) and Lalya have higher grain and straw yield levels, and thus, may play a significant role in addressing the food and nutritional security of the tribal people.

• Traditional Rice Seed Conservation and Sharing with Farmers

In the Palghar district of WGR, the community-based rice seed banks supported by non-governmental organizations (NGO), i.e., BAIF–Development and Research Foundation, have played an important role in traditional rice–germplasm conservation and production with the active involvement of the local farmers. These NGOs have mobilized the farmers to conduct seed exhibitions and personal interactions with fellow farmers for sustainable rice production under rainfed conditions [15]. Further, the farming community is also involved in the conservation and revival of indigenous crops in 56 villages of the 5 tribal CBDs spread across the Nandurbar, Gadchiroli, Ahmednagar and Pune districts in the WGR, with a major focus on TRVs. Presently, 15 villages in Gadchiroli, 12 in Nandurbar, 10 each in Palghar and Ahmednagar, and 5 in Pune district are involved in producing seeds and operating community seed banks for preserving TRVs [16].

• Farmers’ Willingness to Conserve Traditional Rice Varieties in WGR

The farmers’ willingness to conserve TRVs in WGR majorly depends on the survival ability of TRVs, particularly under harsh environmental conditions. Farmers’ socio-economic status also plays an important role in the conservation of TRVs. Thus, the farmers’ participatory farming practices, biodiversity conservation initiatives and promotion of market linkages would go a long way in conserving traditional rice ecosystems in the study region. Although only 39 TRVs were documented out of the 61 TRVs commonly found in the Palghar district of Maharashtra, the WGR is in fact home to ~500–700 TRVs across the WGR ecosystem of the Karnataka, Kerala and Tamil Nadu states of India.

3.1.2. Traditional Rice Varieties in Karnataka’s Western Ghats Region

In Thirthahalli CBD of Shivamoga district of Karnataka, the important TRVs are being documented under current field survey (

Table 4. Traditional rice varieties in Karnataka’s Western Ghats region.

S. No.	Rice Landrace	Characteristics/Benefits
1	Karigajivili	Medicinal properties as per traditional knowledge
2	Karijaddu	A red rice variety used for treating diseases in north Karnataka
3	Doddabyranellu	A popular red rice variety used for treating various ailments
4	Kempusannakki	Traditional variety
5	SannakkiBatta	Medicinal properties as per traditional knowledge
6	Jolaga rice	Red rice variety popular among farmers
7	Sannavalya rice	Popular traditional variety in Thirthahalli CBD
8	Boiled rice (Jolaga)	Red rice variety popular among farmers

). TRVs such as Karigajivili, Karijaddu, Doddabyranellu, Kempusannakki and Sannakki Batta are climate-resilient in nature and conserve the natural biodiversity in WGR [17]_, besides having good medicinal properties.

3.1.3. Traditional Rice Varieties in Kerala’s Western Ghats Region

In the biodiversity-rich Wayanad district of Kerala, around 62 rice varieties are prominently cultivated by the farmers. However, the most popular TRVs are viz. Gandhakasala, Jeerakasala, Kayama, Thondi (

Table 5. Traditional Rice Varieties in Kerala’s Western Ghats Region.

S. No.	Common/ Local Name	Characteristics and Benefits	Pest and Diseases Resistance	Grain Yield (t/ha)
1	Gandhakasala [A.No.: F50S7609503]	Scented rice with good aroma and small granular grains, good nutritional value with pleasant taste, matures in 180–190 days	Disease-resistant but susceptible to lodging because of tall plants	2.0–2.7
2	Jeerakasala [A.No.: F40S7509502]	Scented rice with slightly longer and slender grains, aromatic with white kernel. Good nutritional value with fine taste. Photo insensitive in nature and matures in 180–190 days	Disease-resistant	2.0–2.7
3	Kayama	Small, round and aromatic white kernel; crop matures in 150–180 days	-	1.9–2.0
4	Chomala [A.No.: F30S7409502]	Small, slender, reddish colored straw, aromatic white rice ideal for meals. It contains good amounts of the antioxidant oryzanol, and is rich in vitamin E. Matures in 165–180 days	Suitable for direct-seeding in uplands	-
5	Thondi [A.No.: F80S7909506]	Aromatic rice	Drought-tolerant cultivar	-
6	Chennellu. [A.No.: F60S77O9]	Two types of grains (yellow and bright red grains). Crop duration is 120–125 days	Red rice is grown in coconut gardens and yellow rice is suitable for growth in wetlands	-
7	Velumbala	White rice with long, slender and aromatic grains; crop duration is 180 days	Cultivar better suited to kharif season	-
8	Njavara	Tall plants, seed coat brown in color, non-waxy grains.	Good for wetlands in summer and uplands in kharif season	-

). Other TRVs, such as Chomala, Chennellu, Velumbala and Njavara, also perform well in the region [18]. Hence, this region has been designated as a special rice conservation zone in order to conserve the TRVs for climate-resilient agriculture in the region. The farmers reported that NGOs, such as MS Swaminathan Research Foundation, have greatly emphasized the importance of the conservation and utilization of TRVs through community-based seed conservation activities and individual farmers’ efforts. Eventually, in 2008, the Protection of Plant Varieties and Farmers’ Rights Authority (PPVFRA) of the Government of India recognized the on-farm conservation of 20 varieties by the tribal communities under the ‘Genome Saviours’ program in the Wayanad district [19]. At present, about 648 farmers in the district are cultivating different TRVs across an area of ~392 ha [20].

3.2. Traditional Rice Varieties in Eastern Coastal Region

India’s Eastern Coastal Region (ECR) is one of the major rice growing regions, comprising irrigated deltas of the rivers viz. Cauvery, Krishna, Godavari, Indrāvati and Mahanadi, all of which allow the farmers in the ECR to raise two to three rice crops a year. On the other hand, the coastal drainage area is well suited to rainfed rice cultivation. Similarly, low laying coastal areas characterized by coarse sandy to fine loamy soils, slightly calcareous, moderately saline to alkaline, and low in nitrogen, phosphorus, zinc and organic matter, are well suited to well adapted TRVs [21,22], as the TRVs possess tolerance against salinity and submergence conditions and also grow well under low input intensive agriculture. Thus, these diverse TRVs could provide valuable genetic resources that may provide the ecological balance lacking in the HYVs prevailing in farming situations throughout the ECR. The delta region is generally affected by the river water disputes in the kharif season and heavy flood and cyclone conditions in the rabi season, thus, leading to yield reduction as a result of crop lodging or field dryness [23]. Hence, this study has documented some of the popularly practiced TRVs that may bring climate-resilience to rice farmers whose fields are in the low-lying ECR (

Table 6. Popular Traditional Rice Varieties in Cauvery Delta of the Eastern Coastal Region.

S. No.	Common/ Local Name	Characteristics and Benefits	Insect-Pest and Disease Resistance/Climate-Resilience	Medicinal Value and Other Uses	Duration (Days)	Yield (t/ha)
1	Kuli Vedichan	Good for sandy clay, saline and alkaline soils and coastal areas	Drought, pest- and disease-resistance.	Good for lactating women	110	2.4
2	Sooran Kuruvai	Dark brown grain with granular texture	Drought, flood and cyclone tolerance	Reduces body weight	130–135	3.0
3	KudaiVazhi	Red rice with granular texture, suitable for idly, dosa preparation	Suitable for water logging drought and flood conditions	Cures digestive issues	120–125	3.5
4	Kalurundai	Bold rice with yellow and black color strips. Good for saline soils.	Resistant to insect-pests and diseases; drought, flood and cyclone tolerance	Straw used for roof thatching purposes	120	3.5
5	Soolai Kuruvai	Good in clay-loam and coastal saline soils, bold and brown color grain.	Suitable for irrigated and rainfed and drought, flood tolerance	Straw used for cattle feed and roof thatching	130–140	2.8
6	Val Sivappu	Red rice, good for saline sandy clay	Drought, flood and cyclone tolerance	-	145–150	2.3
7	Chinna Ponni	Yellow color grain	Drought- and flood- tolerant		140	-
8	Kichedi Samba	Pale white color grain	Resistant to pests, diseases, drought and flood	Good for some skin diseases	140	2.8
9	Vai Kunda	Good for direct-sowing and transplanting	Tolerant to drought, flood and weeds	-	145–150	3.4
10	Pichavari	Good for direct-seeding and transplanting	Tolerant to drought, flood and cyclone	-	110–120	4.8
11	Seeraga Samba	Small fine grain. Useful for biryani preparation	Drought, flood and cyclone resistance	It is an aromatic rice	120–130	3.7
12	Vellai Kuruvai Kar	Yellow color grain. Good for direct sowing in upland conditions	Insect-pest and disease, drought and flood tolerance	Good for meal, idli and dosa preparation	120–135	3.5
13	Mappilai Samba	Small ovular grain. Rich in fiber	Tolerant to drought, flood and cyclone	Treats mouth ulcers, digestion disorders and diabetes	160 days	-
14	Thuya Malli	White grain with fine quality	Pest and disease resistance	Increases nerve strength	140	3.0
15	Karuppukavuni	Black rice suitable for direct-sowing in red and black soils, drylands	It requires lower quantities of water having non-lodging habits	Good for making sweets	150–170	4.5
16	Poongkar	Tall cultivar, good for coastal sandy and saline soils	It grows well in rainfed conditions	It gives physical strength	80–90	1.0
17	Sigappukavuni	Red rice contains high levels of anti-oxidants, rich in vitamin B6	Drought tolerance	Prevents heart diseases, asthma and obesity	140	-
18	Muttakar	Red rice with coarse quality	Drought tolerant	-	120	3.2
19	Neelan Samba	Red rice with course quality	Good for water logging condition. Brown plant hopper- (BPH) and earhead bug-resistant	Good for lactating women	175–180	-
20	Kavuni	Black rice rich in iron and vitamin E. Good for making noodles and cakes	-	Good food for pregnant women	-	-
21	Pisini	Red rice with coarse quality. Good for making dosa, porridge and aval	Drought tolerant	High level of anthocyanin, an antioxidant	120	3.7
22	Karudan Samba	White rice with fine quality	Pest and disease-resistant	Gluten-free rice	165	3.4
23	Kaattuyanam	Tall variety good for making idly, dosa, flattened rice	Good for flood conditions	Treats diabetes and heart diseases	170	3.2
24	Kottara samba	Red rice good for idly, dosa, and gruel purposes. Gluten free grain	Resistant to pests and diseases	High fiber, treats diabetics and helps to lower cholesterol	150	-
25	Kullakkar	Good for idly, flake rice, dosa vermicelli and porridge. Good for alkaline soils	Hardy plant, resistant to pests and drought	High zinc and iron content. Lowers bad cholesterol and blood sugar	90–105	3.0
26	ArupathamKuruvai	Red rice good in rainfed areas. Useful for making idly, dosa, puttu and meals	Suitable for all seasons. It can be cultivated five times within a year	Prevents diabetes and good for heart health and bones	60	-
27	Kaivara samba	Small bold grain rice good for idly, dosa, and meals	Drought, flood, cyclone, salinity, pest and disease resistance	Good for diabetic patients	140	3.4
28	Karunkuruvai	Red rice useful in Siddha medicine. Removes impurities, toxins and controls bad cholesterol	-	Treats arthritis, elephantiasis, and chicken pox. Controls diabetes and improves immunity	90–110	-
29	Kaalanamak	Fine quality scented rice. Easily digestible with longer shelf-life.	Resistant to panicle blast. Performs well in saline and sodic soils of pH 9.0 to 9.5	Treats diseases related to kidney, skin, blood and brain.		-
30	Pullangadu	-	-	Good for diabetes and treating paralytic attacks	90–110	-
31	Perungar	Good for preparing idly and dosa	Stem borer-, earhead bug-resistant. Good for water logging conditions	-	120–130	3.5
32	Samba Mozsanam	Red rice with coarse quality good for dry-sowing and transplanting	Good for growing in vicinity of lakes	Good for idly, dosa flattened rice preparation	160–165	4.5
33	Vadan Samba	Dull white grain with coarse quality	Drought, pest/disease resistance	-	155–160	3.0
34	Sembalai	Dull white grain	Resistant to pests and diseases		100–105	2.8
35	Thang Samba	Fine and long grain with golden color	-	Improves condition of skin	150–165	3.7
36	Kaliyan Samba	Red rice	Good in low laying areas	Resistant to pests and diseases	140	3.0
37	Puluthikaar	Red color bold rice. Good for rainfed land and gardens	Resistant to drought		125–130	3.8
38	Kuthiraival samba	Yellow rice	Resistant to lodging, waterlogging, pest and diseases	-	140–150	3.3
39	Chandikaar	Good for black, red and saline soil	Resistant to blight disease and lodging	Fast growing nature		2.0
40	Kuliparichan	Tall variety. In grain, outer color is dark and inner is white	Suitable for coastal sandy soils, drought-resistant	Cooked rice has long shelf-life	-	2.5
41	Vellaiponni	Fine grain quality	Good for alkaline and saline soils	Good for raw rice and fodder	-	-
42	Norungan	Rich in iron, magnesium and vitamins	-	Regulates good cholesterol	120	4.6
43	Aathurkichili	Small sized grain. Rich in calcium and iron	-	Ideal for meals. Good for diabetics	150	3.6
44	Illupaipoo Samba	White rice with fine quality	Suitable for overcoming natural calamities	Treats paralysis and increased body heat, diabetes and joint pains	105–135	-
45	Kuzhi Adhichan	Red rice rich in antioxidants and calcium	Good in saline soils, resistant to drought	Good for lactating women	120	-
46	Sadakar	Grown in sandy soils	Pest- and disease-resistant (except leaf folders)	-	-	-
47	Kottuponni	Red colored bold rice. Good for inter-cropping with coconut and banana	Drought tolerant, pest- and diseases-resistant	Rich in protein, fiber and calcium	120–140	-
48	Milaghu Samba	White and fine rice. Resembles pepper. Good for making gruel	-	Controls joint pains, gives strength	115–130
49	Salem Senna	Long slender grain. Good for making gruel	-	Good for bones, muscles and nerves	135–140	2.5
50	Sanna Samba	Light brown rice	Good in sandy clay soils	Good for making idli and dosa	140	-
51	Rasagadam	White rice with fine quality good for making pongal	Suitable for mountainous regions. Good in sandy clay and alluvial soils	-	125	-
52	Kamban Samba	Dull white rice with fine quality	Good in clay soil and SRI planting	Good for making pongal	120
53	Varappukkodanchan	Red rice good for rice cruel	Good in rainfed farming. Drought tolerance and pest resistance	Good energy supplement	90–100	2.2
54	Poovan Samba	Red and bold rice	-	Good for food consumption	150	-
55	Sempili Samba	-	Highly resistant to pests and diseases	-	120	-
56	Valaan Samba	Good for women’s health, particularly pregnant women	Resistant to pest and diseases	Strengthens pelvis bone. Supports normal delivery	140	-
57	Rajamudi	Good for making idly, dosa, idiyappam, puttu and meals	Pest and disease resistance	Gives high immunity against diseases	135–140	-
58	Sornamusiri	Scented rice, good for biriyani preparations	-	It gives strength	150	-
59	Kanda Sali	Aromatic rice good for Pongal preparation	Tolerance against floods, heavy winds	-	125	-
60	Sornavaari	Good for Idli, dosa preparation	Tolerant to droughts	-	120	-
61	Paal Kudavaalai	Rich in antioxidants and fiber	Flood, pest and disease resistance	Good for diabetes, intestine ailments and constipation	130–145	-
62	Kaarnel	Good for making idli, dosa	-	-	130	-
63	Kappakkar	Brown rice good for making idly and dosa. Good for clay soils	Resistant to pests and diseases, drought and waterlogging		150–160	3.5
64	Koompazhai	Brown rice with coarse quality.	Good in sandy soil and waterlogged areas	Straw used for roofing material	130–135	3.2
65	Sivappukuruvikaar	Brown rice with coarse quality. Good for making idly and Dosa	Resistant to pests and diseases. Good in sandy clay soils	Heavy grain and good yielder. It delays the hunger.	125–130	-
66	Karuthakkaar	Good fiber, manganese, selenium and thiamin contents	It requires more water to grow. Good in flood-affected areas	Good for diabetes, heart health.	140	-
67	Mathimuni	Red rice of moderate quality	Preferred cultivar in sandy clay, clay and alluvial soils	Good for making meals, idly and dosa	140–150	-
68	Ottadam	Hill area cultivar	Pest and disease resistance	Raises energy levels and alleviates tiredness	160–175	-
69	Navara	This variety has many medicinal uses: Good for diabetes patients, prevents premature hair-loss, rectifies basic illnesses affecting the circulatory, respiratory and digestive systems. Ideal for anemic patients.			140	-

).

The medicinal benefits of TRVs as revealed by the farmers of the Eastern Coastal Region highlighted that the Karuppu Kavuni TRV provides protection against cancer and supports insulin secretion; Mappilai Samba strengthens the body, in particular the nervous system; Poongar helps in normal delivery of pregnant women and mothers’ milk secretion; Kattuyaanam is good for diabetics and for treating digestive issues; Illupai Poo Samba is used to treat paralysis and leg pains; Arupathaam Kuruvai treats bone related issues; Kuli Yadichan is good for lactating women and helps to control diabetes; KudaiVazhi cures digestive issues; Zeeraga Samba improves skin health; and Surakuruvai reduces body fat and regulates body weight (Table 6). Based on the information provided by the farmers in the study area (ECR) the matrix ranking of these TRVs was also calculated (

Table 7. Matrix Ranking of Traditional Rice Varieties of Eastern Coastal Region of Tamil Nadu.

S. No.	Traditional Varieties	Resistance to Insect-Pests, Diseases	Climate Resilience (Drought and Floods)	Suitability for Light Soils	Eating Quality	Yield and Market Price	Cost of Cultivation	Length of Straw for Thatching	Medicinal Value	Total Value	Rank
1	Seeraga Samba	4	5	5	6	5	5	4	4	38	5
2	Pichavari	4	5	4	3	6	4	4	5	35	8
3	Kudai Vazhi	5	6	4	5	3	5	4	5	37	6
4	Arupatham Kuruvai	5	5	5	5	5	5	5	4	39	4
5	Norungan	5	5	5	4	5	5	4	5	41	2
6	Aathurkichili	4	4	4	5	5	4	4	3	33	10
7	Kalurundai	4	3	4	2	4	3	3	4	27	16
8	Vai Kunda	5	3	4	3	4	4	3	3	29	14
9	Vellaikkuruvai	4	5	3	3	4	3	2	4	28	15
10	Kichedi Samba	3	3	3	5	3	3	3	2	25	18
11	Mappilai Samba	5	5	4	6	5	5	4	6	40	3
12	Thuya Malli	5	5	4	3	3	4	4	3	32	11
13	Karuppukavuni	5	5	4	2	5	5	4	4	34	9
14	Karudan Samba	3	4	3	3	3	3	3	2	24	19
15	Kaattuyanam	4	5	4	3	4	3	3	4	30	13
16	Kaivara Samba	3	3	2	3	2	3	3	3	22	20
17	Karunkuruvai	4	4	4	3	4	3	3	6	31	12
18	Perungar	4	3	4	2	3	4	2	4	26	17
19	Samba Mozsanam	5	6	5	5	6	5	5	5	42	1
20	Thanga Samba	4	4	5	5	4	5	4	5	36	7

Note: 6 = Best; 1 = Worst; Ranking is calculated based on the number of items chosen for ranking. There are twenty varieties ranked 1 to 20.

). Out of above 69 TRVs of ECR, 20 were perceived as having major importance from a cultivation point of view.

Rice Biodiversity Saving through Community Seed Banks

The traditional rice farmers in the ECR have collectively formed the farmers’ movement ‘Save Our Rice Campaign’ with about 343 TRVs having been revived by a network of 520 farmers [24]. Among these varieties, the farmers are producing quality seeds of 174 traditional varieties [25]. These TRVs give relatively lower yields (~3 t/ha) over 5.0–5.5 t/ha in HYVs; however, these are still greater than the national average yield (2.9 t/ha). The ECR region is facing the problem of the underperformance of short duration HYVs and hybrids. However, the TRVs possess unique traits, such as the ability to withstand drought like conditions and surviving inundation during excessive rainfall, soil salinity and waterlogged conditions, combined with a lower cost of cultivation, and are more remunerative to farmers [25]. Traditional rice farmers also host traditional rice seed festivals every year and exchange the traditional rice seeds with each other, thereby conserving the traditional rice gene pool. These TRVs are also evaluated in ~1160 ha of research farms in delta districts of the Trichy, Tanjore and Tiruvarur in the ECR. At present, an area of 16,800 ha is covered by TRVs in the Cauvery delta area in the Trichy, Tanjore, Tiruvarur, Nagapattinam, Tiruvannamalai, Kancheepuram, Villupuram, Erode, Dindigul and Kanniyakumari districts of Tamil Nadu state in the ECR [26].

3.3. Traditional Rice Varieties of Tribal Dominated Chhattisgarh in Central India Region (CIR)

The Chhattisgarh state of India is conventionally known as the ‘Rice Bowl’ of India. Over 20,000 TRVs have been recorded in the state. Chhattisgarh farmers have developed and conserved many TRVs and landraces over the generations to suit different agro-climatic conditions of the state. These varieties offer an unexplored naturally available gene-pool [27]. These TRVs have tolerance and resistance against climate change risks, insect-pests and diseases. These TRVs protect the rice biodiversity in the tribal dominated central highland forest areas of Chhattisgarh state. The exploration of secondary data sources revealed that among 12 promising TRVs in the tribal region of Bastar, Chhattisgarh, 7 important climate-resilient TRVs are viz. Chudi Dhan, Turia Kabri, Lal Dhan, Lal Chudi Dhan, Gudma Dhan, Tulsighati, and Jondra-Dagd [28]. TRVs such as Gathwan, Maharaji and Laicha have long been used for medicinal purposes. The Gathwan variety is used to treat arthritis. Similarly, Laicha is used by villagers in the CIR to treat skin-related problems [29]. The Basabhog and Asamchudi varieties give good yields under systems of rice intensification [30].

3.4. Traditional Rice Varieties of Assam in North Eastern Region

Assam state in the North-Eastern Region (NER) is home to several TRVs. The Action Plan on Climate Change 2015–2020 reported that Assam state falls under greatest climate sensitivity and vulnerability with lowest adaptive capacity category [31]. The region faces rise in ambient temperature, less irrigation water, soil health degradation, floods, droughts, pests and diseases; which badly affect rice production levels. Under this situation, the commercial rice varieties are failing to provide targeted yields while TRVs may play an important role in stabilizing rice production of Assam state. Hence, the conservation and management of such TRVs is required. The farmers of Assam region have documented ~250 TRVs. The secondary data sources explored in current study revealed that there were 13 important TRVs in Assam state of NER (

Table 8. Traditional rice varieties of Assam in North-Eastern Region.

S. No.	Seasonal Class	Rice Variety	Growing Season	Duration (Days)	Varietal Characteristics
1	Ahu (autumn rice)		March/April	80–130	Early maturing varieties, photoperiod insensitive in nature
	Sub-class	Dumai	March/April	80–90	Red rice used for broadcasted sowing
		Murali	March/April	90–100	Red rice used for broadcasted sowing
		Chengri	March/April	90–100	Red rice used for broadcasted sowing
		Ahu	March/April	>100	Transplanted rice
2	Sali (winter rice)		June/July–November/December	150–180	Transplanted rice, long duration, photosensitive
	Sub-class	Sali	June/July–November/December	150–180	Coarse grain quality
		Lahi	June/July–November/December	150–180	Medium grained
		Joha	June/July–November/December	150–180	Fine grain and scented rice
		Boro	June/July–November/December	150–180	Sticky rice
		Chakuwa	June/July–November/December	150–180	Soft rice with low amylose content
		Asra	April/May–December/January	240–270	Medium–deep water rice, broadcasted or transplanted in lowlands
		Bao	April/May–December/January	270–300	Deep water rice, grown broadcasted
3	Boro (summer rice)		November–May/June	180–200	Photo insensitive, cold-tolerant at vegetative stage, transplanted in marshy lands with minimal tillage
4	Hill rice (Jhum)		March/April–September/October	210–250	Photo insensitive. Good cultivar for hill slopes as direct-seeded

Source [34].

). In NER, four types of rice are grown in Assam: Sali (winter rice), Ahu (autumn), Boro(summer) and Bao (deep-water rice), with various traits such as stickiness, high starch content, waxy and aromatic characteristics. Assam state experiences high rainfall with subtropical climate. The lower Brahmaputra river valleys constitute a very important source of rice production in NER, but mostly affected by floods throughout the year. The TRVs are climate resilient and show tolerance to floods [32]. These TRVs have aroma, stickiness, black color with flood-tolerance [33].

4. Conclusions

The Western Ghats, East-Coastal Region, Central Highlands and North-Eastern Regions of India are rich in rice biodiversity. The traditional rice varieties (TRVs) of these regions possess unique climate-resilience traits, such as ability to withstand drought like conditions, surviving inundation during excessive rainfall, tolerance to soil salinity and water-logged situations, tolerance/resistance to pests and diseases, in addition to having a reduced cost of cultivation. Thus, TRVs may prove remunerative to resource-poor small and marginal farmers of these rice agroecologies. The current study documented 164 TRVs in these four major rice producing regions of India. Some of the TRVs also exhibited unique traditional medicinal properties, as per knowledge preserved by the Siddha and Ayurveda medicine systems. It was revealed that many of the documented TRVs are still not registered under PPVFRA, Government of India. Hence, this study is suggestive of taking greater cognizance of the TRVs for their conservation, need-based crop improvement, and inclusion for large-scale cultivation with the support of governmental agencies, traditional rice farmers, farm scientists, policy makers and mainstream research and academic organizations in India and across the globe to achieve the UN’s Sustainable Development Goals.