Effect of radiation-modified kappa-carrageenan as plant growth promoter on peanut (Arachis hypogaea L.)

Highlights: • Radiation-modified kappa-carrageenan can improve the agronomic traits of the different peanut varieties. • Optimum concentration of 60 ppm of radiation-modified kappa-carrageenan is needed to treat plants. • Over 30% increase yield in peanuts can be obtained with the application of radiation modified carrageenan. - Abstract: The effects of radiation-modified kappa-carrageenan (RMKC) as plant growth promoter (PGP) were determined on peanut varieties, namely: Namnama 2 (NSIC 2007 Pn 14), Biyaya 14 (NSIC 1999 Pn 06), and Likas (NSIC 2001 Pn 09). Improved agronomic traits, such as faster seed germination and flowering, enhanced plant height and pod production and heavier seed weight, which translated into greater total yield, were observed. The highest yield value obtained was 224% more than the negative control (tap water) and 98% higher than the farmers' practice of using an inoculant by supplementing with foliar spraying of 60 ppm RMKC three times. Under field conditions, foliar application of 100 ppm RMKC resulted in greater yield components, with a 25% higher pod yield than the farmer's practice for Biyaya 14% and 34% yield advantage for Likas. RMKC was also found to be as effective as a commercial PGP but requires a lower concentration.