Performance evaluation of climate resilient rice varieties in Lakhimpur district of Assam

Introduction

Rice plays a critical role in the food security and economic growth of India, with the largest area (44.5 m ha) of the world and second highest production after China. It is the major food crops of Assam occupying an area of 23.08 lakh ha with a total production of 60.04 lakh tones (2022-23). Among different types of rice (Ahu, Sali, Boro and Bao) grown in Assam, winter (Sali) rice is considered as most important crop occupies an area of 18.51 lakh ha with a productivity of 26.35 q/ha (2022-23) (Anomymous, 2023) [1] . The occurrence of flood and followed by drought like situation across the state of Assam causing severe losses in production was observed during recent years. In Assam recent data shows that almost 9.3 lakh ha area was affected by flood, of which half of the area is chronically flood prone (Anomymous, 2019) [2] . Due to heavy and continuous rainfall in the monsoon, flood occurs from the month of June to September which is the peak time for cultivation of winter rice in Assam (Anomymous, 2022) [3] . Flood occurs at different growth stages of crop for different duration and variable depth of standing water. Lakhimpur is one of the district of Assam which is affected by severe flood in most of the times and also facing sometimes drought like situation due to aberrant climatic condition. Traditional long duration winter rice varieties having very low productivity are normally grown in the district and only 62,465 ha area is occupied by high yielding varieties of winter rice. These traditional long duration rice varieties are not having submergence and drought tolerant ability. Hence an On Farm Trial was conducted to evaluate climate resilient rice varieties (CR Dhan 801 and CR Dhan 802) having both submergence and drought tolerance ability against the submergence tolerant rice variety Ranjit sub 1 during kharif season of 2022 at farmers' field of Lakhimpur district of Assam.

Materials and Methods

The On Farm Trials was conducted at different locations of the district covering three numbers of farmers' during kharif, 2022 in three different villages viz. Digpukhuri, Pukhuriporia and Orangbasti of Lakhimpur district of Assam. Flash flood affected plots of different villages were selected and all the information related to flood and drought as well as productive performance of existing traditional varieties grown in the villages were collected from the participating farmers. The technological options (TO) consisted of two climate resilient varieties of winter rice viz., CR Dhan 801 and CR Dhan 802 and one submergence tolerant winter rice variety Ranjit sub 1 (check) were tested in the farmer's field (Table - 4 . All the varieties were sown on 23 rd June, 2022 in the nursery bed in all the locations. The crop was transplanted during 20 th to 22 nd July, 2022 with the seedling age of 28-30 days maintaining a spacing of 20 cm x 15 cm. After transplanting, the experimental plots were affected by flood for nine days w.e.f. 5 th to 13 th Oct, 2022. During the crop growth period drought like situation were also observed. Rainless period for three times, first during 14 th -20 th Aug, 2022 (7days), second during 24 th -28 th Aug, 2022 (5 days) and third during 7 th -16 th Sep, 2022 (10 days) were also observed. The recommended fertilizer dose of @ 60-20-40 kg N, P2O5 and K2O/ha was applied as half of N and whole dose of P2O5 and K2O at the time of final puddling. The remaining part of N was applied half at tillering stage i.e., 20-30 days after transplanting and other half at panicle initiation stage. Different observations viz., Plant height, days to 50% flowering, days to maturity, numbers of effective tillers per plant, number of grains per panicle, yield, Gross return, Net return and Benefit Cost ratio (B: C) were recorded.

Results and Discussion

The recorded data shown that among all the three rice varieties, CR Dhan 801 and CR Dhan 802 attained almost similar plant height with the maturity duration of 141-142 days (Table -3). On the other hand, the check variety Ranjit Sub 1 attained slightly more plant height (130.2 cm) and matured in 151 days. Both the variety CR Dhan 801 and CR Dhan 802 had more numbers of effective tiller/ hill (14.8 and 14.7) than the check variety Ranjit Sub 1 (13.6). Different varieties having different tiller number might be due to the variety's unique genetic potentiality (Dangc et al, 2021) 5 . The varieties CR Dhan 801 and CR Dhan 802 recorded almost same yield of 50.2 q/ha and 50.1 q/ha respectively against the check yield of 49.6 q/ha (Ranjit Sub 1). The various economic parameter such as cost of cultivation, gross return, net return, benefit cost ratio was calculated based on the input and output prices of commodities prevailing during the year of experiment (Table -3). The economic indicator clearly revealed that net return from the variety CR Dhan 801 and CR Dhan 802 were almost similar (Rs. 21,664/ha and Rs. 21,534/ha) and higher than the check variety Ranjit Sub 1 (Rs. 20,884/ha). The benefit cost ratio of 1.50, 1.49 and 1.48 were recorded for the variety CR Dhan 801, CR Dhan 802 and Ranjit Sub 1 respectively which was slightly higher in case of CR Dhan 801 than other two varieties. This is due to more yield obtained under improved variety as compared to check variety.

Conclusion

The climate resilient winter rice varieties viz., CR Dhan 801, CR Dhan 802 with more numbers of effective tillers observed even in case of submergence and drought like situation recorded slightly higher yield than the check variety Ranjit Sub 1. Therefore, it can be concluded that along with submergence tolerant rice variety Ranjit Sub 1, the climate resilient rice varieties CR Dhan 801 and CR Dhan 802 may also be cultivated considering the yield and economic benefits for the farmers of Lakhimpur district of Assam. Moreover, prolong dry spell during the cropping period may affect the yield and yield attributes of crop and in that case both the climate resilient rice varieties CR Dhan 801 and CR Dhan 802 may show the better yield performance than the existing recently popular submergence tolerant rice variety Ranjit sub 1.

Acknowledgement

AcknowledgementThe authors are thankful to Assam Agricultural University, Jorhat, Assam and ICAR-NRRI, Regional Rainfed Lowland Rice Research Station, Gerua, Assam, India for providing seeds for conducting the on farm trails. Also thankful to the Director, ICAR-ATARI, Guwahati, Assam, India for extending financial support

References

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2. Anonymous. Climate Resilient Technologies and Rice Value Chain. IRRI Supported Activities. Assam Agribusiness and Rural Transformation Project (APART); 2019.
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4. Anonymous. Suitability Atlas for rice-based cropping systems of Assam under Assam Agribusiness and Rural Transformation Project (APART); 2022.
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