In vitro digestibility as screening tool for improved forage quality in triticale

Context or Problem

Small grain forages are considered an alternative to maize, a globally important forage crop on dairy farms. Triticale is one of the most promising small grains to be cultivated as a source of forage. The inclusion of triticale in the crop rotation system can widen a narrow maize rotation, increase biodiversity, and improve the humus balance. However, successful implementation of the use of triticale forage depends largely on its forage quality, of which digestibility is the most important characteristic.
Objective or Research Question

The main objectives of this study were to investigate the genetic variation for in vitro digestibility (IVD) on total plant and stem level in a diverse triticale collection and to identify traits that can assist breeders in selecting for improved IVD.
Methods

The collection consisted of 120 winter triticale genotypes (103 varieties and 17 breeding lines) of North-American and European breeding origin. These genotypes were cultivated in micro plots in two consecutive growing seasons and harvested at the soft dough maturity stage (Z85, Zadoks scale). Forage quality traits were estimated on total plant and stem samples using near infrared spectroscopy (NIRS).
Results

The dataset showed considerable genotypic variation (CV 3.9–10%) and broad-sense heritability values between 0.66 and 0.73 for total plant in vitro digestibility of organic matter (plant IVOMD), total plant in vitro digestibility of neutral detergent fibre (plant IVNDFD), and stem IVNDFD. Our results show that low total plant acid detergent fibre (ADFom) can be used as a selection criterion to improve plant IVOMD and plant IVNDFD. In turn, stem Klason lignin (KL) has the highest potential for improving stem IVNDFD. Multivariate analysis combining all traits investigated, revealed clustering according to North-American or European breeding origin. In general terms, the European genotypes have higher IVD than the North-American genotypes.
Conclusions

In conclusion, high phenotypic diversity and high heritabilities were detected for triticale forage quality on total plant and stem level in a collection of European and North-American triticale.
Implications or Significance

This study suggested the potential for improvement of triticale forage IVD, indicating total plant ADFom and stem KL might be relevant traits in triticale forage breeding. Promising genotypes with a good plant IVOMD and high forage yield are of relevance for future triticale forage breeding purposes.