Abstract 188

Bainton,-SJ; Plumb,-VE; Drake,-MD; Juliano,-BO; Capper,-BS

Tropical Development and Research Inst., London, UK.

Ruminant feeding systems utilizing fibrous agricultural residues - 1986. Proceedings of the Sixth Annual Workshop of the Australian-Asian Fibrous Agricultural Residues Research Network, Los Banos, 1-3 April 1986 [edited by Dixon, R. M.]. 1987, 115-120; 8 ref. Canberra, Australia; International Development Program of Australian Universities and Colleges Limited (IDP).

Forty-six varieties of rice straw were harvested from 2 trials being carried out by the International Rice Research Institute (IRRI); 22 were taken from IRRI's Demonstration plot and 24 from the International Rice Yield Nursery (IRYN) trial. Each was separated into 4 morphological components (blades, leaf sheaths, stems, and stubble) which were subsequently analysed for cellulase solubility in vitro, the results being expressed on both a DM basis (DMS) and an organic matter basis (OMS). Varieties from both trials gave similar results. The whole rice plant (excluding the panicle) was composed of about 25% blade, 50% stubble, 10% stem, and 15% sheath. Harvest index was about 0.5 and the ash value was 14%. Correlations between the morphological fractions and the other plant characteristics such as height, days to flowering/maturity, and harvest index were highly significant. The OMS of the individual plant components ranged from 25.5% for the sheath fraction to 43.8% for the stem. Whole straw (excluding the stubble fraction) ranged from 23.9% to 40.4% OMS. Correlations between plant components and DMS of the upper straw were only slight, the stem proportion being the most significant. Results indicate that breeding of early-maturing, short-stemmed varieties for high grain yield is not detrimental to the nutritive value of the straw.