MSc

An investigation entitled “Micronutrient management of sweet corn (Zea mays var. saccharata) hybrids for yield and quality” was undertaken with the objectives to evaluate the performance of sweet corn hybrids for yield and quality and to study the role of zinc and boron in increasing the productivity, quality and profitability of the crop. The study was carried out at College of Agriculture, Padannakkad and Regional Agricultural Research Station, Pilicode during 2019-2020. The experiment was laid out in factorial randomized block design with 12 treatments replicated thrice. The treatment combinations included three hybrids viz., H1- Sugar 75, H2- KSCH 333, H3- Misthi and four levels of micronutrient application viz., M1- RDN of Maize as per KAU POP (control), M2- RDN of Maize as per KAU POP + Spray of Boron as Solubor @ 0.15 per cent once at tasseling and silking, M3- RDN of Maize as per KAU POP + Spray of Zinc as ZnSO4 @ 1.0 per cent at 20 and 40 days after sowing and M4- RDN of Maize as per KAU POP + Spray of Boron as Solubor @ 0.15 per cent once at tasseling and silking + Spray of Zinc as ZnSO4 @ 1.0 per cent at 20 and 40 days after sowing.
Perusal of the results on growth attributes revealed that sweet corn hybrids did not significantly influence plant height, number of leaves, leaf area, days to 50 per cent tasseling and silking, days to maturity and number of harvests. However, significant effects of hybrids were recorded in dry matter production. Highest dry matter accumulation was noticed in Sugar 75 (12027 kg ha-1) and was statistically on par with Misthi (9962 kg ha-1). Recommended dose of nutrients alone had resulted in highest plant height at 15 DAS and was on par with combined foliar application of zinc and boron. Leaf area was recorded maximum at 15 and 45 DAS in control plot and at 45 DAS, the treatment was on par with foliar application of zinc. Number of days taken for 50 per cent tasseling, silking and maturity was least in the control plot. Number of harvests did not differ significantly with micronutrient application. However, growth attributes did not show any significant variation between hybrids and their interaction with zinc and boron.
Hybrids did not differ in any of the yield attributes recorded. However, total cob yield and green stover yield varied significantly with hybrids. Among the different hybrids tested, Sugar 75 was superior recording a cob yield of 11102 kg ha-1. Green stover yield was the highest in Sugar 75 (20667 kg ha-1) and was on par with Misthi (19111 kg ha-1). Among the yield attributes, the highest cob length was noticed in the control plot and was on par with foliar application of zinc and boron. Maximum cob girth was recorded in the control plot and was statistically on par with foliar application of zinc. Cob weight without husk was maximum when treated with recommended dose of fertilizers alone and was on par with foliar application of boron. Foliar nutrition with either zinc, boron or both had no influence on number of cobs per plant, number of kernel rows per cob, number of kernels per cob, hundred fresh kernel weight, cob weight with husk, total cob and stover yield. Visual symptoms of boron deficiency were observed in cobs irrespective of the treatments. The hybrids and their interaction with foliar application of micronutrients did not show significant influence on yield attributes. However, maximum cob yield (11640 kg ha-1) was recorded when recommended dose of nutrients alone were given and among interaction effects, the highest cob yield (13813 kg ha-1) was recorded when Sugar-75 was provided with recommended dose of nutrients alone and was on par with KSCH 333 and recommended dose of nutrients alone (13247 kg ha-1).
Organic carbon and available boron content in the soil was not significantly influenced by hybrids, micronutrient application and their interaction. However, after harvest, there was an increase in the organic carbon content in the soil. Available boron content in the soil was in deficient range before and after the experiment.
Chlorophyll content did not vary significantly with hybrids and micronutrient application. Highest chlorophyll content (2.44 mg g-1) was recorded when KSCH 333 was treated with recommended dose of fertilizers alone and was on par with all the interaction effects except when KSCH 333 was treated with foliar application of zinc and boron. Ascorbic acid content and moisture content was not significant among treatments.
Among the hybrids, mean per cent damage by fall army worm was recorded the lowest in Misthi. Micronutrient application and their interaction with hybrids did not significantly influence the pest incidence.
Highest net profit of ₹ 225710 ha-1 and BCR of 2.03 was realized with Sugar 75.
Therefore, it can be concluded from the study that growing sweet corn hybrid Sugar 75 is beneficial for getting higher yield per unit area and maximum economic returns. Visual symptoms of boron deficiency were evident, reflected as unfilled kernel rows within the cobs of sweet corn. The study also reveals that boron is a critical nutrient that influences the yield and yield attributes in sweet corn. Foliar application of boron @ 0.15 per cent once at tasseling and silking did not meet the requirements of the crop when grown in boron deficient soil. Hence, foliar application of a nutrient alone cannot alleviate the nutrient deficiency in the crop when grown under limited soil nutrient supply.