Response of pre-released Kharif sorghum (Sorghum bicolor L. Moench) genotypes to different fertility levels under rainfed environment

Introduction

Sorghum [Sorghum bicolor (L.) Moench] is one of the important cereal crop in India because of large size of among other grain millets is called 'Great millet' and it was introduced to India from East Africa. Though the area of Kharif sorghum is decreasing year by year, the production and productivity is in increasing trend due to high yielding genotypes and advanced technology. Identification of good quality sorghum genotypes and development of location specific production technology offer an excellent opportunity to enhance the productivity. Among the production factors, fertilizer plays a vital role in deciding the yield of sorghum. The nutrient requirement further increases with the use of high yielding cultivars and also soil moisture availability. The newly released varieties and hybrids respond differently to different fertility levels depending upon the type of root system and their root density. Hence, there is need to optimize the fertilizer quantity required to obtain higher productivity. With this context, the performance of various sorghum genotypes was evaluated to different fertility levels under rained condition.

Materials and Methods

A field experiment was conducted to study the "Response of pre-released Kharif Sorghum genotypes to different fertility levels under rainfed environment at All India Coordinated Research Project on Sorghum, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, Karnataka during kharif 2020-21. Dharwad is situated at 15 0 29' North latitude and 74 0 59' East longitude at an altitude of 689 m above mean sea level and comes under northern transitional zone (Zone-8) of the agro-climatic zones of Karnataka. Soil of the experimental site was clay with a good water holding capacity. Recommended fertilizer was 100:75:25 kg N:P2O5:K2O /ha. The experiment consisted of 32 treatment combinations comprising four fertilizer levels 0% RDF, 50% RDF (50:37.5:12.5 NPK Kg ha -1 ), 100% RDF (100:75:25kg NPK ha -1 ) and 150% RDF (150:112.5:37.5 NPK Kg ha -1 ) and eight sorghum genotypes (G1-SPH-1888, G2-SPH-1914, G3-SPH-1912, G4-SPV-2568, G5-SPV-2569, G6-CSH-25, G7-CSH-30, G8-CSV-20 including checks) with two replications. The field experiment was laid out in a split plot design.

As per the treatments, half dose of nitrogen and full dose of phosphorus and potassium was applied in through urea DAP and MOP. Remaining half of the nitrogen was applied at 30 days after sowing. Sowing of sorghum genotypes was done manually with a row spacing of 45cm and 15cm between plants. Thinning was done by retaining one plant per hill to maintain optimum plant population. All the other agronomic practices were followed uniformly in all the treatments. The data collected from the experiment was subjected to statistical analysis as described by Gomez and Gomez (1984) [3] . The level of significance used in F test was P=0.05.

Results and Discussion

Fertility levels

The data presented in Table 1 revealed that, the linear increase in growth, yield parameters, grain and fodder yield. Application of 100% RDF (100:75:25kg NPK ha -1 ) recorded significantly higher grain (55.54 q/ha) and fodder yield (10.77 t/ha) over 0 and 50% RDF and it was on par with 150% RDF. The per cent increase in grain yield was to an extent of 62.48 and 10.55 higher over 0% and 50% RDF respectively. Significant improvement in higher grain fodder yield could be attributed to profound influence of N and P fertilization on growth and development of the crop due to increase in nutrient accumulation and their translocation to sink. Similar results were reported by Sumeriya et al., (2005) [5] The higher grain yield at 100% RDF might be related to higher of yield parameters viz., grain weight (57.5 g/panicle) and 100-seed weight (3.06 g), The better performance of these yield parameters might be attributed to mineral nutrition especially nitrogen which plays an important regulative functional role in plant system through synthesis and translocation of growth hormones which help in better growth and development of plant (Bringer at al., 1980) [1] . Similarly, the same treatment realized significantly higher gross returns (Rs. 111341/ha), net returns (Rs.70323/ha) and BC ratio (2.73) compared to 0% and 50% RDF which was due to higher grain and fodder yield (Table 2). The results are in agreement with the findings of Mali et al., 2000 [4] .

Performance of genotypes

Among genotypes, the test variety SPV-2568 exhibited significantly higher grain yield (59.05q/ha), Stover yield (10.0 t/ha), gross returns (Rs.116401/ha), net returns (Rs.76950 /ha) and BC ratio (2.93) as compared to checks (CSH-25, CSH-30 and CSV-20) but was on par with SPV-2569. The per cent increase in grain yield was to the tune of 27.3, 33.9 and 54.09 over CSH-25, CSH-30 and CSV-20 respectively. The higher grain yield was mainly due to higher grain weight (54.5 g/panicle) and higher 100-grain weight (3.29 g). Similarly, the same variety exhibited significantly higher fodder yield (10.01 t/ha) over checks and was on par with SPV-2569 (Table 1). The better performance of the new varieties and hybrids was due to influence of nutrients on protein synthesis, involvement in several physiological and metabolic processes in the plant system (Tisdale et al., 1990) [6] . Further, significantly higher gross returns (Rs. 116401), net returns (Rs. 76950) and BC ratio (3.33) was recorded with SPV-2568 over checks but was on par with SPV-2569 (Table 2). The higher returns were mainly due to higher grain and fodder yield.

Interaction effect

The data on interaction effect of fertility levels and genotypes revealed that, the new variety SPV-2568 produced significantly higher grain yield of 66.35 q/ha with 150% RDF compared to others but at par with 100% RDF (65.31q/ha) (Table .3). These results were in conformity with the findings of Dashora et al., (2014) [2] .

Conclusion

Based on the experimental results, it could be inferred that, application of 100% recommended doze of fertilizer (100:75:25kg NPK ha -1 ) found optimum for kharif sorghum genotypes for getting higher grain yield, fodder yield and net returns. Further, test varieties SPV-2568 and SPV-2569 produced higher grain yield compared to check varieties (CSH-25,CSH-30 and CSV-20).

References

1. Bringer KA, Gore SR, Banarjee G. Waterlogging injury in sorghum seedlings and their kinetin affected rapid recovery. Plant Growth Regulation. 1980;41:23-31.
2. Dashora LN, Gupta G, Solanki NS, Mundra SL, Kaushik MK. Response of sorghum (Sorghum bicolor) genotypes to different fertility levels in South Rajasthan. In: Proceedings of the National Symposium on Agricultural Diversification for Sustainable Livelihood and Environmental Security; 2014 Nov 18-20; Ludhiana, Punjab. 2014.
3. Gomez KA, Gomez AA. Statistical procedures for agricultural research. 2nd ed. New York: John Wiley & Sons; 1984. p. 241-271.
4. Mali AL, Sumeriya HK, Singh I. Yield and monetary returns of sorghum cultivars under different fertility levels. Agricultural Science Digest. 2000;20:168-170.
5. Sumeriya HK, Singh P, Mali AL. Studies on the effect of fertility levels on growth and productivity of sorghum (Sorghum bicolor (L.) Moench). Crop Research. 2005;30:69.
6. Tisdale SL, Nelson WL, Beaton JD. Soil fertility and fertilizers. 4 th ed. New York: MacMillan Publishing Company; 1990.