Weed Tolerance and Suppressive Ability of Potato Cultivars to Natural Weed Infestations

Abstract Concerns such as herbicide-resistant weeds and environmental pollution have increased an interest in using weed-competitive crop cultivars for weed management. Potato plants are highly vulnerable to weed competition, especially during early and late growing seasons. In this context, a two-year field experiment assessed weed tolerance and suppressive ability of 15 genetically diverse potato cultivars to natural weed infestations. The results showed that weed interference significantly reduced potato growth and yield. For instance, weed competition reduced plant height by 10–37%, plant fresh weight by 21–44%, plant dry weight by 15–40%, and yield by 15–48%. Potato cultivars varied in their ability to suppress and tolerate weeds, with weed dry weight ranging from 146.7 g m −2 in Lady Olympia to 428.3 g m −2 in Arizona and tuber yield from 13.84 t ha −1 in Electra to 25.15 t ha −1 in Agria under weedy conditions. Key traits of weed-suppressive cultivars included early emergence, rapid canopy development, and greater plant biomass. Cultivars with greater plant height and higher yields were generally more weed tolerant. Lady Olympia demonstrated the highest weed suppression among the evaluated cultivars, reducing weed dry weight by 60% or more, making it suitable for organic farming systems. Agria exhibited superior weed tolerance with minimal yield loss, making it ideal for conventional high-yield farming systems.