Does genetic diversity of grass improve yield, digestibility, and resistance to weeds, pests and disease infection?

Abstract

ABSTRACTIntraspecies genetic level diversity has the potential to improve ecosystem functions and services, similar to that by species-level diversity. Although yield, pollination, and pest and disease control have been enhanced by crop genetic diversity, mixing multiple cultivars of grass within a species in an agricultural field have not been fully tested by farmers.We, therefore, tested whether multiple ecosystem functions are increased in a grass mixture of multiple cultivars compared to monoculture and whether this relationship differs with soil fertility. We performed monocultures of four Orchard Grass cultivars and a mixture of these cultivars with and without fertilizer application and examined the aboveground net primary productivity (ANPP), their stability, dry matter digestibility, and resistance to weed, pest, and disease. We found significant differences between cultivars in the second yield and disease lesion area on the leaf, but not between mixed culture and monoculture. Moreover, no significant difference was found in the first and third yields in terms of stability, dry matter digestibility, and leaf damage by insects, although the number of leaves damaged by insects for mixed culture was less than half of that on average for monoculture. Although genetic diversity is not always an important driver of ecological processes due to fluctuation among plots, it may play a role in pest control of agricultural land in the long term.