Forage production, morphological, and chemical composition of diploid and tetraploid cultivars of Italian ryegrass in hydromorphic soils.

This study aimed to evaluate forage mass, morphological, and chemical composition of diploids and tetraploids Italian ryegrass cultivars in hydromorphic soil. Eight ryegrass cultivars were evaluated in a two-years completely randomised trial with four plots per cultivar. Forage production was recorded, and samples were collected to evaluate morphological and chemical composition. The contrasts methodology was used to verify differences between diploid and tetraploid cultivars. Compared to tetraploids, the diploids had the greatest number of cuts and the largest accumulation of forage in the second year, highlighting the better adaptation of cultivars in hydromorphic soils. Tetraploid ryegrass increased leaves and reduced stem and inflorescence proportion relative to diploid ryegrass. Tetraploid cultivars had lower DM, organic matter, and acid detergent fibre content than diploid cultivars. However, there was no significant difference between cultivars associated with their ploidy for the neutral detergent fibre and estimated total digestible nutrients. Additionally, only in the second year, tetraploid had lower crude protein content than diploid ones. Tetraploid ryegrass showed be less tolerant to periods of water stress due to flooding, characteristic of hydromorphic soils, resulting in less forage production than diploid ryegrass. [ABSTRACT FROM AUTHOR]