The Response of Corn (Zea mays L.) Hybrids with Different Maturity Groups to Low Dose Application of Nicosulfuron Herbicide
Subject Areas : Journal of Crop Ecophysiology
Iraj Rooki
1
(
MS.c. Graduated Department of Agronomy and Plant Breeding, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran.
)
M. Armin
2
(
Associate Professor, Department of Agronomy and Plant Breeding, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran.
)
Matin Jamimoeini
3
(
Assistant Professor, Department of Agronomy and Plant Breeding, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran.
)
Keywords: weed, cultivar, Yield loss, herbicide dose,
Abstract :
To investigate the response of corn varieties with different maturity groups to low dose applications of nicosulfuron herbicide, a split plot experiment with a randomized complete block design with three replications was carried out in Barekat Jovain Agricultural Company (Sabzevar, Razavikhorasan province) in 2017. Factors were: corn hybrids (early maturing (single cross hybrid 260, medium maturing (single cross hybrid 400) and late maturing (single cross hybrid 704) varieties as main plot and subplots five herbicide low dose applications (0, 25, 50, 75 and 100% recommended dose (50 g.ha-1 a.i. nicosulfuron) and with one weed free treatment. The results showed that, the late maturity hybrid had higher plant height, ear weight, number of rows per cob, number of seeds per row, cob weight, and seed number in cob, economic yield, biological yield, weed density and weed dry weight than other hybrids. Increasing doses of herbicide increased plant height (0.64%), ear weight (39.45%), number of rows per cob (8.93%), number of seeds per row (30.15%), seed weight (10.68%), number of seed per cob (40.63%), economic yield (41.82%), biological yield (14.95%)and decreased weed density (70.88%)and weed dry weight (82.17%) as compared to that of weedy condition. Although use of herbicide to reduce weed dry weight in late maturing hybrids was more than early and medium maturing hybrids but the use of the recommended herbicide dose had the same effects on weed control. 75% of the recommended dose in all three varieties produced the same yield as compared to the recommended dose. But in the late maturity hybrid, 50% reduction in recommended doses could be similar to the recommended dosage. In general, it can be said that increasing the length of the plant growth period allows the use of lower doses of herbicide than the recommended dose.
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