LEAF ANATOMICAL CHARACTERIZATION OF Hymenachne amplexicaulis (RUDGE) NEES GENETIC RESOURCES

Abstract

The leaf anatomy of 32 ecotypes of Azuche, Hymenachne amplexicaulis (Rudge) Nees pasture grass native to México was compared to identify valuable forage attributes within the native genetic diversity. Plant material was obtained from a pasture collection established and evaluated by the Colegio de Postgraduados at La Huerta, Jalisco experimental station of Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP). The percentage and variability of foliar tissues (epidermis, bulliform cells, mesophyll, aerenchyma, sclerenchyma, vascular bundle sheath, phloem, and xylem) were measured through histological analysis and image segmentation on cross foliar sections 28 days after regrowth. Data were analyzed using multivariate methods and analysis of variance. There was no intraspecific variation (P ≤ 0.05) among ecotypes; however differences (P ≤ 0.05) were observed among groups formed based on foliar tissues: 1) highly digestible, 2) medium digestible and 3) non-digestible. Laboratory analyses allowed the identification of forage quality ecotypes. Ecotypes with high digestible tissue proportion (mesophyll and aerenchyma) were identified, which may be important for genetic selection. Genetic variability of Azuche is available for evaluation, and the species possesses high productive potential under irrigation in tropical environments, which needs to be documented in detail.