チモシー(Phleum pratense L.)1番草における栄養価の遺伝率  [in Japanese] Heritability of Nutritive Value in First Crop of Timothy (Phleum pratense L.)  [in Japanese]

チモシー1番草における栄養価関連形質の広義および狭義の遺伝率を把握するため,15の栄養系とその後代系統を同年同一圃場で栽培し,近赤外分析法(NIRS)を用いて栄養価関連形質を推定した。その結果,栄養価に関する3指標(低消化性繊維(Ob)/細胞壁物質(OCW),0b含量および可溶性炭水化物(WSC)含量)は(1)狭義の遺伝率が高く,(2)指標相互間の遺伝相関は効率的な並行改良が可能である相関か,もしくは弱い相関で,(3)同一熟期内であり,収量性で選抜がなされた材料においては,乾物重とこれらの指標との遺伝相関は弱かった。したがって,これら3指標を用いた個体選抜で効率的な改良が可能であり,また指標相互間の並行改良および収量性と栄養価の並行改良は可能である,との結論に達した。

It is important to improve the nutritive value of timothy (Phleum pratense L.) by breeding for enhancing animal productivity. In order to estimate the heritability in the broad and narrow senses of the nutritive value in first crop of timothy, the samples of 15 clones and their polycross progeny lines, both of which had been cultivated in the same environment, were analysed by near infrared reflectance spectroscopy (NIRS). The results suggested that (1) the heritability in the narrow sense is high in three nutritive indices, low digestible fiber (Ob)/ organic cell wall (OCW) ratio, Ob and water soluble carbohydrate (WSC) contents, (2) the genetic correlations among the indices are effective for simultaneous improvement or weak, and (3) the genetic correlations between the dry matter weight and the indices are weak on the condition that the materials have been selected in yield and as long as they belong to the same maturity. Therefore, it was concluded that the nutritive value of timothy not only can be improved effectively by individual selection procedures with the indices but also can be improved simultaneously among the indices and with yield.