Effects of plant growth regulators and potassium on growth and yield of finger millet

Impact of plant growth regulators viz., benzyl amino purine (BAP 50 ppm), brassinolide (BL 0.5 ppm), and nutrient like KCl (1%) alone and with combination on growth and growth analytical parameters, and yield of finger millet by foliar spray at panicle initiation stage under rainfed condition was studied in field experiment. The treatments including control, KCl, BAP, BL, KCl + BAP, KCl + BL, BAP + BL and KCl + BAP + BL and different growth and growth analytical parameters were estimated. Combination of KCl, BAP and BL registered highest root length (17.2 cm), leaf area (425.3 cm), leaf area index (1.82) and leaf area duration (55.7 days) compared to other treatments. Higher specific leaf weight and crop growth rate were recorded by KCl + BAP, and BAP + BL, respectively. The highest grain yield of 22.5 Q/ha was recorded by KCl + BAP + BL. Introduction Eleusine coracana L. Geartn called as finger millet and Ragi belonging to Poaceae and is one of the most important cereals in India after wheat and rice and ranks third in importance among millets in the world after pearl millet and foxtail millet (Upadhyaya et al. 2007). Finger millet is well adapted to heat and drought that prevails in marginal and degraded soils and has relatively better nutritional value. Because of its superior adaptability, it plays an important role in supporting marginal agriculture, such as that commonly practiced in semi-arid regions of India (Ravi et al. 2010). The high nutritive value compared to other cereals and grown in sterile soil makes finger millet as one of the salient crops among resource poor communities living in food insecure areas. Finger millet is a popular food among diabetic patients in the countries like India. Hence, finger millet is considered as ‘poor man’ and also ‘rich man crop’. The alarming increase of population growth, drought and erratic rainfall has been the main cause of food insecurity (AsnakeMekuriaw 2006). Drought is one of the most common environmental stresses that affects growth and development of plants. Even though, finger millet is drought tolerant crop, the yield potential is reduced when it is grown under rainfed condition. There is less chance of nutrients application through soil under rainfed condition. Hence, foliar application of nutrients, plant growth regulators and with consortia is possible to alleviate the drought effect and also enhance the productivity of crop under rainfed condition. Prabha et al. (2016) reported that the foliar application of plant growth regulators (PGRs) and nutrients twice at 50 and 70 days after sowing was found to give better yield and economic returns. Foliar application of potassium improved the drought tolerance, growth and yield components in wheat (Aown et al. 2012). Chang et al. (2016) reported that the exogenous application of cytokinin delayed leaf wilting under drought stress. Hence, the present study was undertaken to enhance the productivity of direct sown finger millet by using PGRs and nutrients under rainfed condition. *Author for correspondence: <sivatnau14@gmail.com>. Crop Physiology Division, Regional Research Station-TNAU, Paiyur, India. 224 SIVAKUMAR AND SURENDAR Materials and Methods The experiment was carried out at field number F1, Regional Research Station, Tamil Nadu Agricultural University, Paiyur by using finger millet variety Paiyur 2 seeds, sown directly to the field with the spacing of 22.5 × 10 cm after the receipt of sufficient rainfall (37 mm). PGRs and nutrient solutions were prepared, separately, and treatments consisting of BAP (50 ppm), BL (0.5 ppm), KCl (1%), KCl + BAP, KCl + BL, BAP + BL and KCl + BAP + BL were applied as foliar spray at panicle initiation stage (60 days after sowing) and control was maintained with water spray. The experiment was carried out in RCBD with one variety imposed with eight treatments in three replications. Plant height was measured from the ground level to the tip of the growing point. The plant was uprooted, and the root was taken with minimum damage and the length from the stem base to the root tip was measured. Number of leaves was determined by counting the leaves from the base to tip of the plant in each replication and mean value expressed in numbers. Leaf area per plant was measured by using leaf area meter (LICOR, Model LI 3000). Uprooted plant samples, after washing the root portion, were first shade dried and then oven dried at 80C for 48 hrs. The dry weight of the leaf was recorded and expressed as g/plant. Leaf area index (LAI) was calculated by employing the formula of Williams (1946) as follows. LAI = Leaf area per plant/ground area occupied by the plant. Leaf area duration (LAD) was determined by using the formula of Power et al. (1967) as follows and expressed in days.