Indigenous folk rice cultivars often possess remarkable but unrevealed potential in terms of nutritional attributes and biotic stress tolerance. The unique cooking qualities and blissful aroma of many of these landraces make it an attractive low-cost alternative to high priced Basmati rice. Sub-Himalayan Terai region is bestowed with great agrobiodiversity in traditional heirloom rice cultivars. In the present study, ninety-nine folk rice cultivars from these regions were collected, purified and characterized for morphological and yield traits. Based on traditional importance and presence of aroma, thirty-five genotypes were selected and analyzed for genetic diversity using micro-satellite marker system. The genotypes were found to be genetically distinct and of high nutritive value. The resistant starch content, amylose content, glycemic index and antioxidant potential of these genotypes represented wide variability and ‘Kataribhog’, ‘Sadanunia’, ‘Chakhao’ etc. were identified as promising genotypes in terms of different nutritional attributes. These cultivars were screened further for resistance against blast disease in field trials and cultivars like ‘Sadanunia’, ‘T4M-3-5’, ‘Chakhao Sampark’ were found to be highly resistant to the blast disease whereas ‘Kalonunia’, ‘Gobindabhog’, ‘Konkanijoha’ were found to be highly susceptible. Principal Component analysis divided the genotypes in distinct groups for nutritional potential and blast tolerance. The resistant and susceptible genotypes were screened for the presence of the blast resistant pi genes and association analysis was performed with disease tolerance. Finally, a logistic model based on phenotypic traits for prediction of the blast susceptibility of the genotypes is proposed with more than 80% accuracy.

Germplasm is the basis of all plant improvement programmes. The collected landraces of rice possessed high probability of the useful genes for efficient application in the breeding programmes to develop high yielding varieties with quality and resistance to biotic and abiotic stresses. Those landraces needs to be conserved ex situ or in situ. In the rice repository of Uttar Banga Krishi Viswavidyalaya, Pundibari has about 200 landraces collected from West Bengal, Assam and Manipur. Every Kharif season, they are being cultivated and seeds are collected to conserve since 2008. High variability has been observed among those varieties. Some special characteristics also have been identified during characterization and ex situ conservation of those landraces, such as, long and white sterile lemma, double and triple kernelled spikelets. Important landraces were used as donor in rice improvement. A number of desirable mutants, recombinant lines and somaclones have been have been developed which are in different yield trials. Some pure lines also have been isolated from the collected famers’ varieties.

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The landraces of rice play an important role as donor in breeding of varieties for desirable traits. One hundred twenty-one Farmers’ Varieties (FVs) of rice collected from West Bengal, Assam and Manipur had used to characterize the physical parameters of seeds. Based on the kernel length and L/B ratio, most of the FVs were found to be long bold (31 FVs) and short bold (47 FVs). Out of the remaining 43 FVs, 27 were long slender, 03 were short slender and 11 were medium slender. Rice seeds were also classified based on test weight. Most of the FVs were medium-heavy (50 FVs) and heavy (27 FVs). The yield of the FVs varied from 0.91 t/ha to 5.19 t/ha. Jadudhan (5.19 t/ha) was found to be the maximum seed-yielding genotype followed by Jaldhyapa-1 (4.92 t/ha), Jagratikartik (4.69 t/ha), Jamainaru (4.68 t/ha), Kerala Sundari (4.58 t/ha), Satiya (4.44 t/ha), Dubari Komal (4.32 t/ha), Jugal (4.08 t/ha), Boichi (4.06 t/ha), Patanai (4.06 t/ha), UBL-4 (4.05 t/ha) and Khayamdhan (4.01 t/ha). From this collection, donors may be selected for breeding long-grained rice as well as rice with high test weight.