|Publication Type:||Journal Article|
|Year of Publication:||2012|
|Authors:||Ashikaga, K, Tanaka, T, Fujii, H, Deguchi, K, Iida, K|
|Keywords:||First crop, genotype ranking, Nitrogen fertilization, nutritive value, Phleum, timothy|
Improvement of the nutritive value of timothy (Phleum pratense L.) through breeding should result in enhanced livestock productivity. This study evaluated the effect of genotype (G) × nitrogen (N) fertilization interaction (G × N) on the nutritive value of the first crop of timothy in northern Japan. Five traits, the contents of low-digestible fiber (Ob), water-soluble carbohydrate (WSC), mono- and disaccharides and fructan and the ratio of Ob to organic cell wall (OCW), were investigated as quality traits for 16 clones under three N rates (3, 7 and 11 g N m–2 as low, standard and high levels, respectively). The G × N effects were non-significant in all the traits despite the significant main effects of G and N in all or most of the traits. Coinciding with this, there were significant correlations among the three N rates for Ob, WSC, fructan contents and Ob/OCW ratio. Correlations between the low and high N rates showed weaker trends than those between the standard and low N rates or between the standard and high N rates in three of the five traits. Fructan content showed small standard deviations and ranges, indicating the difficulty of using it as a selection index for evaluating the genetic variation. The results suggest that, for the Ob and WSC contents and the Ob/OCW ratio as the desirable traits, the relative ranking of genotypes is almost consistent across different N application levels and selections for the traits at the standard N level are of potential use for effective improvement of the nutritive value of timothy.
|Short Title:||Grassland Science|
Evaluating the genotype × nitrogen fertilization interaction on the nutritive value of the first crop in timothy (Phleum pratense L.) clones