Cell Wall Constituents in Plant Parts of Reed Canarygrass Clones1
- P. Marum and
- A. W. Hovin2
Forage dry matter intake potential by ruminants is negatively associated with cell wall constituent concentration (CWC%) above a critical level. Two experiments were conducted to determine the effects of leaf blade, leaf sheath, stem, and maturity on total CWC% (TCWC%) to improve selection procedures in breeding of reed canarygrass (Phalaris arundinacea L.).
Three clones, previously characterized as being high, medium, and low in T-CWC%, were sampled 11, 29, 33, 44, 55, and 66 days afer growth started in spring. Throughout the sampling period the clone with high T-CWC% had the largest proportion of stems and the low T-CWC% clone had the smallest proportion of stems. The CWC% in leaf sheath and stem tissues of all clones increased with age through anthesis. After anthesis, no consistent CWC% change took place due to formation of new shoots from stem nodes. Mean daily increase in CWC% of stems (1.11%) was twice that of blades (0.59%). Selection plants for low forage CWC% anytime up to anthesis would have given smiliar results for all three clones.
Plant parts of 12 clones, which had been selected previously for different concentrations of CWC, were analyzed at anthesis and regrowth stages. At anthesis, the ranges in CWC among clones were 10.5 percentage points in stems and 5.9 points in blades. For 7-week.old regrowth forage, the ranges were 7.7 percentage points and 7.9 points, respectively. The average CWC% in stems was 19.0 percentage points higher than that in blades at anthesls, and 25.8 percentage points higher in the regrowth forage. Leafy plants had less T-CWC% than did stemmy plants. Leafy plants also tended to have lower CWC% in all plant parts. Dry forage yield was positively co~related with T-CWC%. Path-coefficient analysis suggested CWC% in the stem to be the most important factor affecting total T-CWC% of the forage at anthesis, and CWC% in the leaf blade to be most important in the regrowth forage. At both harvests CWC% in stems and blades were highly correlated.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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