干旱区生态环境知识资源中心

Background: the efficient use of good quality forage represents one of many ways to improve animal productivity and, consequently, reduce the feed costs of dairy farming. Between the wide variety of studies aiming to improve the nutritional value of forage, histological studies, allow for both the comparison of species or cultivars and the monitoring of tissue aging within the plant. Objective: the present work aimed to characterize the stem morphology of Pennisetum clones (Itambe IV-46, Itambe I-1.20, Itambe I-1.4, Milheto x Buacu/112-23.4, Cuba-116-29.3, CAC-262-12.102, Roxo of Botucatu x CAC-282-18.29, Taiwan-146-2.6, Itambe I-1.5, Pusa Napier or 419-76 x Buacu/122-11.2, Taiwan-146-2.03, Taiwan-146-2.85, Itambe II-2.46, Pusa Napier or 419-76 x Cuba-116-12.3 and Pusa Napier or 412-76 x Buacu/122-8.22) into three strata (basal, medium and apical) and three tillers of the plant using histological sections. Methods: the material was collected in a previously established area at the Experimental Station of Sao Bento do Una at the Agronomic Institute of Pernambuco. The materials were distributed in a completely randomized 15 x 3 x 3 factorial design (14 clones and one hybrid, three layers of stem and three tillers). The samples were collected during the dry season beginning in August 2008. Results: there were significant differences (p<0.05) among the clones evaluated, and the average values for the lignified cells in the cortex region ranged from 2.21 to 4.21 for the Taiwan-146-2.6 and Roxo of Botucatu x CAC-282-18.29 clones; however, this was not different from the other clones in the medullary region. The Itambe II-2.46 clone showed the highest absolute value in the percentage of phloem in the cortex region (2.32%) and a high value, with significant differences, in the medullary region (1.59%) compared to the other clones. Conclusion: the highest values of cellulose in the medium and apical regions of the studied stems represent a benefit to grazing animals.