Nutritive Characteristics of Kleingrass at Various Stages of Maturity. I. Chemical Evaluations of Experimental Synthetic Varieties

Previously selected plants for improved lines of kleingrass (Panicum coloratum L.) were evaluated for growth and seed production characteristics. At the initiation of this test, 13 experimental synthetic varieties were available for chemical comparisons of forage quality. This study was conducted to determine if differences existed in percent of neutral detergent fiber (NDF) and NDF components within the available synthetic varieties of kleingrass. The effects of five stages of plant maturity on NDF and its components were also evaluated for each variety. Since kleingrass has an indeterminate type of growth form, plants collected as initial and regrowth forage were harvested when a certain percent of the seed on the most mature kleingrass tillers reached the soft dough stage, but prior to the time- of seed maturation. Previously nonharvested cumulative forage was collected at the same chronological age as the regrowth forage. At each of the maturity-stage dates, plant samples were separated into leaf laminae and stems. Each plant part was analyzed for its neutral detergent solubles:neutral detergent fiber ratio (NDS:NDF). The NDF was then sequentially partitioned into hemicelluloses (HEM), cellulose (CEL), lignin (LIG), and ash. The hemicelluloses further divided into easily hydrolyzable (EHH) and difficulty hydrolyzable hemicelluloses (DHH). Kleingrass varieties differed in NDS:NDF and NDF components. Leaf:stem ratios ranged from 1:1 to 1:4. By harvesting at a morphological stage prior to seed maturation, the NDS: NDF ratio of leaves and stems in regrowth forage did not vary throughout the study period. Leaf laminae contained approximately 34% HEM and 24% CEL; whereas, stems contained approximately 34% HEM and 34% CEL. With advancing maturity, HEM of leaf laminae increased at the expense of CEL. However, the HEM: CEL ratio of stems remained at approximately 1:1 throughout the collection period. The EHH:DHH ratio changed significantly with plant age as percent EHH increased and DHH decreased. The percent of LIG in both leaves (3.2%) and stems (6.6%) changed with plant age but the buildup of LIG was greatest in stems. Acid-insoluble ash was influenced by the stage of growth only in leaf laminae and the leaves, with an average of 2.4%, contained four to eight times more ash than did stem sections.