Climate Crops Centre members, MSc Nemanja Ćuk and MSc Dušan Dunđerski, defended their PhD theses at the University of Novi Sad, Faculty of Agriculture on September 23rd and October 8th, 2024, respectively.
Nemanja looked into the ‘Inheritance of resistance to charcoal rot caused by Macrophomina phaseolina in sunflower’. Within his research, he assessed sunflower genotypes resistance to Macrophomina phaseolina through various field methods and a laboratory cut-stem inoculation technique developed specifically for this research. His findings indicate polygenic inheritance of resistance, and resulted in one molecular marker associated with the resistance.
Nemanja’s work contributed to breeding efforts aimed at mitigating climate-related disease impacts in sunflower production.
Dušan aimed to determine whether ethephon treatment alters above-ground traits of maize, thereby reducing lodging, and to identify the optimal ethephon dosage for minimizing lodging while maximizing yield within his dissertation titled “Effects of Ethephon application on the morphological properties of the aboveground part of maize”
Producers often resort to applying excessive amounts of nitrogen and higher planting densities than optimal, which can substantially increase maize grain yield per unit area. However, these practices, combined with strong winds, frequently lead to lodging, which can reduce grain yield by as much as 25%. The results demonstrated that ethephon application significantly reduced plant lodging under favourable conditions for lodging—by up to 83.45% in lodging-susceptible hybrid and 58.40% in lodging-tolerant hybrid. This reduction led to yield increases of up to 740 kg/ha for lodging-susceptible hybrid and 540 kg/ha for lodging-tolerant hybrid. Using a generalized linear mixed model, he found that both yield and lodging tolerance can be enhanced by optimizing the number of kernels per ear, internode dry weight, ear length, and the ratio of ear height to plant height. Interestingly, the number of green leaves was shown to increase yield without affecting lodging. On average, the highest theoretical grain yield with the lowest lodging was achieved with an ethephon dose of 420 g/ha. His findings suggest that yield and lodging are interdependent traits, revealing a trade-off that can be addressed by focusing breeding programs on the identified traits. Furthermore, he concluded that ethephon application could be an effective strategy to enhance the stability of maize production, particularly in the face of climate change, stormy winds and the associated risk of lodging.
