Performance evaluation of rice varieties and their response to zinc nutrition in uplands

Abstract

A field trial entitled “Performance evaluation of rice varieties and their response to zinc nutrition in uplands” was conducted during Kharif 2019 (May – August 2019) at Coconut Research Station, Balaramapuram. The objective of the study was to find out a suitable rice variety for uplands in red loam tracts of Kerala and to standardize the dose and method of zinc application. The experiment was conducted in Factorial Randomized Block Design with varieties as first factor and zinc sulphate application as second factor in three replications. Three varieties were used for the experiment were Anna 4 (V1), APO 1 (V2), and Prathyasa (V3) and the zinc sulphate application comprised of seed priming with ZnSO4 @ 2g kg -1 seed (S1), foliar application with ZnSO4 @ 0.5 per cent at active tillering stage and panicle initiation stage (S2), combination of S1 and S2 (S3), soil application of ZnSO4 @ 20 Kg ha-1 (S4), and control (without ZnSO4 application) (S5). Crop was manured with FYM @ 5 t ha-1and N:P:K @ 90:30:45 kg ha-1 (Suman, 2018). Varieties had significant effect on plant height, tillers per m2, root shoot ratio and dry matter production (DMP). Among the varieties V2 (APO 1) shown significantly higher plant height and root shoot ratio. Variety V3 (Prathyasa) shown significantly higher tiller m-2 and DMP. Zinc sulphate application had significant effect on growth attributes viz., tillers m-2, Leaf area index (LAI), root shoot ratio and DMP. Combination of seed priming and foliar application (S3) recorded significantly higher tillers per m-2, Leaf area index, root shoot ratio and DMP. Interaction of varieties and zinc sulphate application was significant in tillers m-2, LAI, root shoot ratio and DMP. The treatment V2S4 recorded the highest DMP (11732.37 kg ha-1). Varieties, zinc sulphate application and their interaction shown significant effect on crop growth rate (CGR), relative water content, soluble protein, proline content and stomatal conductance but only zinc sulphate application had significant effect on chlorophyll content. Varieties, zinc sulphate application and their interaction had significant effect on nutrient uptake. Among the varieties phosphorus and Zn uptake was higher in V3 (prathyasa) and potassium uptake was higher in V2 (APO 1). Among the method of zinc sulphate application higher uptake was noted in soil application (S4). Varieties had significant effect on available potassium and zinc. Zinc sulphate application had significant effect on available nutrients after the experiment. Varieties had significant effect on yield attributes viz., panicle length, panicle weight, panicles m-2, filled grains per panicle, sterility percentage and thousand grain weight. However, zinc sulphate application had significant effect only on panicle weight, filled grains per panicle, sterility percentage and thousand grain weight. Among the varieties, the highest number of panicles m-2 and the highest number of filled grains per panicle were recorded in the V3 (Prathyasa). The highest panicle weight was recorded in V2 (APO 1) and the highest panicle length, the highest thousand seed weight and the lowest sterility percentage were recorded in V1 (Anna 4). Among the method of zinc sulphate application, foliar application (S2) recorded the highest panicle weight, combination of seed priming and foliar application (S3) recorded higher number of panicles m-2, filled grains per panicle, the lowest sterility percentage and grains with higher thousand grain weight. Grain yield was also significantly influenced by varieties and zinc sulphate application. Among the varieties, V3 (Prathyasa) recorded significantly higher grain yield among the varieties (3,524.03 kg ha-1). Compared to control, all method of zinc application recorded higher grain yield. Combined application of seed priming and foliar application (S3) recorded the highest grain yield (3,877.71 kg ha-1) among the different methods of zinc sulphate application. The interaction between varieties and zinc sulphate application also had significant effect. Among the varieties, APO 1 (V2) recorded the highest straw yield and it was significantly superior to other treatments. Soil application of ZnSO4 @ 20 kg ha-1 recorded the highest straw yield. Among the varieties, prathyasa (V3) recorded the highest net returns (38,921 ha-1) and B C ratio (1.58). Among zinc sulphate application, S3 (seed priming with zinc sulphate 2 g kg-1 seed + foliar application of zinc sulphate 0.5 per cent at active tillering and panicle initiation stage) recorded highest net returns (47,897 ha-1) and B C ratio (1.71). Considering the yield, economics and B:C ratio, variety prathyasa (V3) performed well with application of NPK @ 90:30:45 kg ha-1,seed priming with zinc sulphate 2 g kg-1 seed + foliar application of zinc sulphate 0.5 per cent at active tillering and panicle initiation stage (S3) for uplands in red loam tracts of Kerala.