Random sample of 45 grams seeds was obtained from the bulk produced from each genotype from each replication the oil content of seeds was obtained by Bench top NMR Analyzer (Oxford instruments, USA).

Approximately 60 g dried seeds were collected from each genotype and crushed into uniform texture using mortar-pestle. The crushed seeds were loaded into Soxhlet to extract oil using petroleum ether (60-80°C) as solvent. The oil was used for fatty acid profiling using gas chromatography with flameionization detector (GC-FID). The oil was converted in to fatty acid methyl ester (FAME) using alkaline catalysed transesterification with 0.5 ml 4 % KOH solution in methanol using standard protocol. The instrument (Thermo-Trace GC Ultra-Al 3000 auto sampler) (Thermo Scientific, USA) was programmed as inlet temperature 210°C and FID detector temperature was 260°C. Oven was kept at 160°C for two minutes. After that an increase of 10°C/min. was applied to raise oven temperature up to 200°C, where it was kept at isotherm for ten minutes. The gas flow rate in column was 1.5 ml/min. and the sample injection volume was 0.2 µl. The capillary was TR FAME-30 m × 0.25 mm, ID × 0.25 µm film. Fatty acids composition of each treatment sample was estimated in percentage by using Chrom-card software associated with GC.

The data were analysed by Microsoft Excel 2010 to derive different ratios among fatty acids as suggested by Shah et al. (2017). Pearson’s correlation coefficients (r) was calculated using PAST 3.22 software (Hammer et al. 2001) to determine significance of correlation among fatty acids at P<0.05.

Castor oil has great value in industry, pharmaceutical and agricultural sectors. The variability in seed oil content ranged from 38.25 to 45.86 % with an average of 42.93 %. Among the genotypes studied, SHB-1019 (45.86 %) was significantly higher for oil content imitated by genotypes namely, GCH7 (45.67%) and GEETA (45.65 %). The genotype, SKI-372 recorded the lowest oil content (38.25 %) (Table 1).

Total saturated fatty acid content in all castor genotype was ranged from 2.27 to 3.38 % with a mean of 2.70 %. It was observed that genotype SKI-370 (3.38 %) had higher per cent of total saturated fatty acid followed by genotypes GEETA (2.98 %), SKI-372 (2.97%), and SH-72 (2.96 %). The genotypes VI-9 (2.27 %) had low per cent of total saturated fatty acid. Total saturated fatty acid content was categorized in two type of acids viz., steric acid (C16:0) and palmitic acid (C18:0) (Table 1). The amount of steric acid in all castor genotypes was ranged from 1.05 to 1.46 % with a mean of 1.26%. Among all the accessions, SKI-370 (1.46 %) contained highest amount of steric acid, followed by genotypes namely, SHB-1005 (1.14 %), GEETA (1.14 %), SKI-373 (1.14 %), and SH-72 (1.40 %). The genotypes, VI-9 (1.05 %) contained lowest amount of steric acid. Palmitic acid content in all castor genotypes was ranged from 1.22 % (VI-9) to 1.92 % (SKI-370) with a mean (1.46 %). From the perusal of data genotype SKI-370 (1.92 %) found the highest amount of palmitic acid, followed by genotypes viz., JI-35 (1.68 %) and 48-1 (1.61 %).

Total unsaturated fatty acid content in all castor genotypes was ranged from 96.64 % (SKI-370) to 98.15 % (VI-9) with a mean 97.30 % (Table 1). Mono unsaturated fatty acid (MUFA) oleic acid (C18:1) content in all castor genotype was ranged from 2.10 % (VI-9) to 4.26 % (GEETA) with a mean of 3.33 %. It was observed that genotype GEETA (4.26 %) had higher per cent of oleic acid followed by genotypes i.e. JI-35 (4.06 %) and SKI-370 (3.97 %) (Table 1). Poly unsaturated fatty acid (PUFA) in castor oil contained linoleic acid (C18:2) and linolenic acid (C18:3) (Table 1). Linoleic acid content ranged from 3.87 to 5.82 % with a mean of 4.96 %. Among the all genotypes the highest per cent of linoleic acid was recorded in 5.82 % for genotype GEETA followed by genotypes, SKI-370 (5.66 %) and SKI-373 (5.41 %). The lowest per cent of linoleic acid was recorded in genotype VI-9 (3.87 %). The values for linolenic acid in castor genotypes ranged from 0.46 (DCS-94) to 0.89 % (VI9) with a mean of 0.59 % (Table 1).

Ricinoleic acid, the predominant mono unsaturated fatty acid varied among castor genotypes from 86.37 to 91.29 % with a mean. Among all the genotypes the higher per cent of ricinolenic acid was recorded in genotype viz., VI-9 (91.29 %) followed by genotype namely, GCH-7 (89.62 %) and SHB1018 (89.48 %). The lowest per cent of ricinolenic acid was recorded in genotypes SKI-370 (86.37 %) (Table 1). The results of the present study are in agreement with the results reported by Huang et al. (2015), Shah et al. (2015), Omari et al. (2015), Omohu and Omale (2017) and Shah et al. (2017). Linolenic acid and oleic acid in castor oil are very much favorable to human health and have been used in the treatments of some human diseases like skin cancer, diabetes, heart attack, high blood pressure, high cholesterol level, renal disease, and lupus (Ganesan et al. 2018). Linoleic acid, palmitic acid, and stearic acid contain certain beneficial properties for the skin, hence utilized in cosmetic industries (Ganesan et al. 2018). Esters of stearic acid: glycol stearate, glycol distearate, and ethylene glycol have been utilized in manufacturing various cosmetic products and in shampoos to increase the pearly effect. The presence of such fatty acids in castor oil offers the industrial and nutritional benefits of castor (Yeboah et al. 2020). The amount of different fatty acids present in castor oil is represented in Fig. 1. Based on the amount of different beneficial fatty acids in the oil, genotypes can be utilized in further breeding programs.

Significant positive correlation was observed between palmitic acid and stearic acid (r = 0.750*). The oleic acid showed significantly positive correlation with palmitic acid (r = 0.691*) and stearic acid (r = 0.498*) (Table 2). These results were resembled with the findings of Shah et al., (2017). The linoleic acid has significantly positive correlation with oleic acid (r = 0.582*), palmitic acid (r=0.670*) and stearic acid (r = 0.794*). However, the linolenic acid has negative correlation with stearic acid (r =-0.088), palmitic acid (r =−0.193), oleic acid (r =−0.509*) and linoleic acid (r =−0.211). In the present study, the ricinoleic acid content was significantly negatively correlated with stearic acid (r =−0.793*), palmitic acid (r =−0.836*), oleic acid (r = - 0.876*) and linoleic acid (r =−0.884*) and positive and nonsignificant correlation with linolenic acid (r = 0.360*) (Fig. 2). These results were in agreement with the findings of Shah et al. (2017).

Different ratios among fatty acids of castor genotypes are shown in Table 3. The Oleic acid/ricinoleic acid ratio among the all the genotypes ranged from 0.023 (VI-9) to 0.049 (GEETA). High oleic acid and low ricinoleic acid content in castor oil is preferable for industrial applications demanding high oxidative stability like bio-fuel requiring lower ricinoleic acid content than the standard castor oil (RojasBarros et al. 2004). The oleic acid/linoleic acid (O/L) ratio among all the genotypes ranged from 0.536 (SH-72) to 0.815 (JI-35). Higher O/L ratio showed higher stability of castor oil (Shah et al. 2015). For the improvement of character through selection, it is necessary to understand the extent of diversity existing for each character in germplasm (Parita et al. 2018). This will enhance the development of new varieties using plant breeding (Gelotar et al. 2019). The estimation of seed oil content and fatty acid profiling can be utilized for selection of parents for population development and improvement in oil quantity as well as quality.