Producción forrajera y semillas de Panicum virgatum, Tripsacum dactyloides y Sporobolus airoides en Tulancigo, Hidalgo

Ante la necesidad de transferir tecnología de pastos de menor uso en agua de riego en el Valle de Tulancingo, el objetivo del estudio fue evaluar tres pastos mexicanos Panicum virgatum, Sporobolus airoides y Tripsacum dactyloides en producción de forraje, densidad de población tallos, producción de semilla y caracterización de semillas de manera física y fisiológica. El estudio se llevó a cabo de abril a agosto y de agosto a diciembre de 2020 en condiciones de riego por goteo con 10 trasplantes en 12 m2 a partir de plantas adultas. El rendimiento mayor de forraje (suma de dos ciclos) y hojas se observó en P. virgatum (3.59 t MS ha-1; P < 0.0001), seguido por T. dactyloides (1.15 t MS ha-1) y S. airoides (0.719 t MS ha-1). La población de tallos vivos acumulada en T. dactyloides fue 216, en P. virgatum 187 y en S. airoides 82 tallos por planta-1 (P < 0.0001). La producción de diásporas en suma de los dos ciclos, en P. virgatum fue 147 kg ha-1, similar (P > 0.05) a T. dactyloides, sin embargo, las cúpulas con incipiente pureza física (0.79 %). La mayor pureza física (14.08 kg ha-1; P < 0.0001) y semilla pura viable (12.3 kg ha-1; P < 0.0001) se observó en Sporobolus airoides.

Tripsacum dactyloides (eastern gamagrass).

Tripsacum dactyloides is cultivated as a forage crop in areas within and outside its native distribution range. The species establishes slowly and competes poorly with annual grasses and weeds during its first year of establishment, but after that, it competes effectively with most perennial and broadleaf plants. Currently, T. dactyloides is listed as invasive only in Cuba. However, this species is often reported to be growing as a 'weed' in ruderal areas, forest edges, and disturbed and open forests in areas within and outside its native distribution range.

Complete Chloroplast Genomes of Saccharum giganteum, Saccharum longisetosum, Cleistachne sorghoides, Sarga timorense, Narenga porphyrocoma and Tripsacum dactyloides. Comparisons with ITS phylogeny and Placement within Saccharum

The first complete chloroplast and Internal Transcribed Sequence (ITS) cassette sequences for the species: Saccharum giganteum, Saccharum longisetosum, Cleistachne sorghoides, Saccharum narenga and Tripsacum dactyloides are presented. Corresponding sequences for a new isolate of Sarga timorense were assembled. Phylogenetic analyses place S. giganteum, S. longisetosum and S. narenga within the Saccharinae but distinct from Saccharum, whilst C. sorghoides emerges as a member of genus Sarga and Tripsacum datyloides as a member of the Tripsacinae. Comparison of chloroplast and ITS phylogenies reveal complex reticulate evolution within the Saccharinae, with S. giganteum, S. longisetosum and S. narenga, despite having the same base chromosome count (15) having different evolutionary origins; making them members of different genera and not members of genus Saccharum. The importance of reticulate evolution in the origins of Andropogoneae, particularly the Saccharinae and the unique positions of Saccharum and Miscanthus is discussed.

Tripsazea, a Novel Trihybrid of Zea mays, Tripsacum dactyloides, and Zeaperennis

A trispecific hybrid, MTP (hereafter called tripsazea), was developed from intergeneric crosses involving tetraploid Zea mays (2n = 4x = 40, genome: MMMM), tetraploid Tripsacum dactyloides (2n = 4x = 72, TTTT), and tetraploid Z. perennis (2n = 4x = 40, PPPP). On crossing maize-Tripsacum (2n = 4x = 56, MMTT) with Z. perennis, 37 progenies with varying chromosome numbers (36-74) were obtained, and a special one (i.e., tripsazea) possessing 2n = 74 chromosomes was generated. Tripsazea is perennial and expresses phenotypic characteristics affected by its progenitor parent. Flow cytometry analysis of tripsazea and its parents showed that tripsazea underwent DNA sequence elimination during allohexaploidization. Of all the chromosomes in diakinesis I, 18.42% participated in heterogenetic pairing, including 16.43% between the M- and P-genomes, 1.59% between the M- and T-genomes, and 0.39% in T- and P-genome pairing. Tripsazea is male sterile and partly female fertile. In comparison with previously synthesized trihybrids containing maize, Tripsacum and teosinte, tripsazea has a higher chromosome number, higher seed setting rate, and vegetative propagation ability of stand and stem. However, few trihybrids possess these valuable traits at the same time. The potential of tripsazea is discussed with respect to the deployment of the genetic bridge for maize improvement and forage breeding.

Observations of Tripsacum dactyloides and T. floridanum (Poaceae): measuring climate and soil gradient effects on Tripsacum in Texas, U.S.A.

Reports of Tripsacum floridanum Porter ex Vasey in Texas have been countered with two arguments. First is that narrow-leafed Texas plants, when grown under favorable conditions, are more typical of wider-leafed T. dactyloides (L.) L. Second is that the offspring from crosses of T. dactyloides with T. floridanum are sterile or partially so. The support for these two claims is examined. The conclusion is narrow-leafed Texas plants typical of T. floridanum are in Texas, and crosses between the two produce fully fertile offspring. This raises the question of what factors are at play to segregate the wider-leafed from the narrower-leafed Texas populations. To investigate, two statistical models were constructed using separate data. First, a simultaneous system of seven equations was used to predict phenological and morphological plant characteristics given environmental factors. Second, a single logit equation predicted the probability of narrow-leafed diploid versus widerleafed diploid and tetraploid plants given environmental factors. Predictions allow for the measurement of plant characteristics from climate and soil gradients. Results suggest that narrow-leafed diploid plants occupy distinct habitats with the larger tetraploid plants coping by adapting mechanisms to overcome interspecies competition while the smaller diploid plants adapt with mechanisms to overcome stress. In conclusion, findings support consideration of T. floridanum as a variety of T. dactyloides and conservation implications are reviewed.