Abiotic stress management for sustainable oilseed production. Abstract: National Seminar on Harnessing the Potential of Panchabhutas (tatvas) for Sustainable Climate Resilient Rainfed Agriculture

Abstract

Abiotic stresses cause negative impact on agricultural production including oilseed crops with non-optimal environmental factors that may act independently or in multiples. These abiotic stresses such as water (drought, flooding); temperature (heat, cold, chilling/frost), rain (erratic; extreme events, unseasonal rain, hail storms and floods); radiation (Ultra violet, ionizing radiation); chemicals (mineral/ nutrient deficiency/excess, pollutants, heavy metals, pesticides, gaseous toxins); mechanical (wind, soil movement, submergence) and salinity, alkalinity and nutrient deficiency are responsible for major reduction in agricultural production. Abiotic stresses cause hindrance not only for the production but also affect the quality of oilseed crops. Among the abiotic stresses moisture, temperature and salinity are the major limiting factors for oilseeds production under rainfed conditions. The occurrence of abiotic stresses at sensitive stages of crop severely limits oilseed crop yields.

The ICAR-IIOR has rich collection of germplasm on mandated oilseed crops. Over the years, IIOR has been working on drought, salinity and thermal tolerance in mandate oilseed crops and identified lines and traits contributing to tolerance to these abiotic stresses. About 264 castor germplasm lines and 250 sunflower lines were screened both in the lab and also in field for various stresses and genotypes with better temperature tolerance (castor-25, sunflower-11) were identified. Sunflower lines /genotypes viz., RGP-46-P3, RGP-21-P6, RGP-60-P1, Phule Bhaskar, KBSH-44, PI-686527, RHA-6D-with drought tolerance, AKSF-6-3B with temperature tolerance, CSFH-12205, CO2, KBSH-44 with salinity tolerance were identified. Also 382 castor (278 germplasm and 104 breeding lines) and 415 sunflower genotypes were screened in root structures and genotypes with better root and WUE traits (castor germplasm-60, parental lines-20) were identified. Few germplasm lines for salinity tolerance during germination were also identified (9 out of 27 screened) in castor. Safflower lines viz., A1, Bhīma, ISF 764 and GMU 2347 performed well under residual moisture conditions in field, confirming their tolerance towards moisture stress through their modulation in canopy temperature and conserved water use. Among 24 safflower genotypes subjected to salinity stress (0, 4, 6, 8, and 10 dS/m), a gradual decline in growth parameters with increasing salinity level was observed. Safflower line SSF-733 recorded highest reduction in dry weight (54% @ EC= 10 dS/m) and least reduction was noticed in IC-406052. Sunflower genotypes with better phosphorus acquisition were identified. Out of the 52 genotypes evaluated, 22 genotypes recorded high P in biomass. Sunflower genotype CMS-42-B was best in P acquisition with 51-52.3% of its uptake was partitioned into seeds and four genotypes (GMU 420, CMS 335, PS 2016 and CMS 42B) were found to accumulate higher P concentration in seed under P stress situation. Sesame core set germplasm was evaluated under terminal drought and irrigated conditions during late rabi season across years. Five genotypes: (IC-204622, IC-132176, IC-132207, IC-205471, and IC-73164) showed high transpiration efficiency, potential root traits, high harvest index and better association with seed yield under water stress. The genotypes IC- 2046222 (brown seeded); IC-132171 (white seeded) were identified and variety JCS 2454 (white seeded) was developed for summer cultivation in Telangana.

The adverse effects of abiotic stresses could be mitigated through different ways viz., development of crops cultivars tolerant against different stresses; adopting soil and moisture conservation practices (Broad Bed and Furrow; Ridges and Furrows method of planting) and other improved management approaches. Research at IIOR on Conservation Agricultural practices in castor based cropping systems with crop-residue management resulted in higher organic carbon rain water use efficiency and maintained favorable soil temperature during offseason/summer. Other management practices include: exogenous application of osmo-protectants. Application of essential macro and micronutrients, organic amendments (compost, green manures, cow dung and incorporation of crop residues) in soils would go a long way in increasing the yield and quality of oilseed crops in sustainable way.