SEED TREATMENT AND POLYMER COATING EFFECT ON GERMINATION, SEEDLING VIGOUR, FIELD PERFORMANCE AND YIELD OF HYBRID MAIZE
Acharya N G Ranga Agricultural University, Guntur
The present investigation was carried out in the Department of Seed Science and Technology, Advanced Post Graduate Centre, Lam, Guntur (laboratory studies) and Agricultural Research Station (ARS), Jangamaheswarapuram, Guntur (field studies) during 2017-18 to study the effect of chemical seed treatment and polymer coating on germination, seedling vigour, field performance and yield of maize hybrid, DHM 117. Initially seed was treated with chemicals i.e.,seed without chemical treatment (S1), seed treated with Thiram @ 3g kg-1 of seed(S2), seed treated with Imidacloprid @ 5g kg-1 of seed (S3) and seed treated with Thiram @ 3 g + Imidacloprid @ 5 g kg-1 of seed (S4).Then the seed was coated with polymer i.e., seed without polymer coating (P1), seed coated with polymer @ 3g kg-1 of seed (P2) and seed coated with polymer @4 g kg-1 of seed (P3). After seed treatment, seed was tested for seed quality parameters viz., germination, speed of germination, shoot length, root length, seedling length, seedling fresh weight, seedling dry weight, seedling vigour index I, seedling vigour index II and root by shoot ratio. Data of seed quality parameters were analysed by adopting Factorial Completely Randomized Design (FCRD). Analysis of variance indicated that the influence of seed treatment, polymer coating and their interaction was significantly different for the various seed quality parameters. The results of the present investigation clearly revealed that the polymer coating of maize hybrid seed showed significant influence on germination, speed of germination and dry weight of the seedling, while chemical seed treatment exhibited significant effect on all the germination and seedling parameters under study except speed of germination and root/shoot ratio. The interaction effects were also observed to be significant for germination, root length, shoot length, seedling length, vigour index-I and vigour index-II. xiii Polymer coating of the seed could not able to improve the germination of maize hybrid seed but enhanced the dry matter production of seedling. Seed treatment with Imidacloprid either alone or in combination with Thiram improved the seedling growth and vigour. Among all the treatments seed treated with Thiram and without polymer coating showed high germination per cent, while seed treated with either Imidacloprid or Thiram + Imidacloprid without polymer coating had better seedling performance. In field studies treated seed was sown in the field in four replications adopting split plot design in order to find out the effect of seed treatment on crop growth and yield contributing parameters viz., days to 50% tasseling, days to 50% silking, days to maturity, plant height at maturity, tassel length, cob length, cob girth, cob weight, number of kernels per row, number of kernel rows per cob, number of kernels per cob, 100 kernel weight and single plant yield. The results of the present investigation clearly revealed that the polymer coating of maize hybrid seed showed significant influence on tassel length, cob girth, cob length, number of kernels per row, number of kernels per cob, 100 kernel weight, cob weight and single plant yield. Chemical seed treatment exhibited significant variation on all the yield parameters except number of kernel rows per cob and the interaction effects were observed to be significant on all the parameters except days to 50% silking and maturity. Seed treatment with a combination of fungicide, insecticide and polymer resulted in improvement in yield and its contributing characters when compared to untreated seed. Among all the treatments used in the present investigation, seed treatment with Thiram @ 3g + Imidacloprid @ 5 g kg-1 of seed registered more cob length, girth, more number of kernels and 100 ker-1nel weight leading to the realization of higher single plant yield. Results obtained from character association analysis indicated that single plant yield had significant positive association with 100 kernel weight. Among the yield contributing characters days to 50% tasseling had highly significant positive association with days to maturity and days to 50% silking, while plant height at maturity showed significant negative association with days to maturity, 50% tasseling and 50% silking. Cob length exhibited significant positive correlation with cob girth and number of kernels per row, where as number of kernels per cob exhibited significant positive correlation with cob length and number of kernels per row.