​Impact of Foliar Spray of Plant Growth Retardants with Potassium on Growth Traits, Gas Exchange Parameters and Grain Yield in Foxtail Millet (Panicum italicum L.)

Abstract

Background: Foxtail millet is one of the nutri-cereal foods for the people of semi arid regions. Proper nutrient management and source-sink alteration are major keys for achieving higher productivity in millets. However, potassium is not recommended to foxtail millet and the potential yield is not exploited. And also the study of source-sink alteration in foxtail millet by using plant growth regulators is meager. Methods: An experiment was conducted to study the impact of plant growth retardants viz., chlormequat chloride (CCC) and mepiquat chloride (MC) with the nutrient potassium (K2SO4 - 1%) on growth, gas exchange parameters and grain yield of foxtail millet under rainfed condition. Plant growth retardants with potassium consortium were used as foliar spray at flower initiation stage under field condition. Standard methods were used to measure the plant height, root length, number of leaves, LAD, CGR and grain yield. The photosynthetic rate, transpiration rate and leaf temperature were measured by using the instrument PPS. Result: Foliar spray of CCC (250 ppm) with 1% K2SO4 showed supremacy to enhance crop growth rate, leaf area duration, photosynthetic rate, transpiration rate and grain yield compared to other treatments. However, lowest plant height (100.7 cm) and number of leaves were observed by CCC (250 ppm) alone. Highest photosynthetic rate (26.84) and transpiration rate (17.94) were registered by CCC + K2SO4. Lowest leaf temperature of 34.1ºC was registered by 1% K2SO4 compared to control (35.6°C). CCC with K2SO4 recorded highest LAD value of 46.1 which is on par with K2SO4 alone (45.9). CCC with K2SO4 registered highest grain yield of 2.13 t ha-1 with increased yield of 18.3% over control. However, highest benefit cost ratio of ratio of 2.75 was recorded by 1% K2SO4 alone.