Mediante el estudio del ADN, un equipo de investigadores del INTA Pergamino –Buenos Aires– busca identificar cuáles son las regiones del genoma y los mecanismos que se ponen en marcha frente al ataque de diversos patógenos. Estos resultados ayudarán al desarrollo de nuevas variedades y será uno de los ejes del XI Congreso Nacional de Maíz.
Trabajos en Prensa
Physical purity and germination of cariopses of Chloris gayana Kunth and Panicum coloratum L. harvested from plants grown in an sodium-alkaline soil
The objective of the study was to evaluate physical purity, germination percentage (G) and germination velocity (GV) of caryopses of Chloris gayana cv. Finecut (Cg) and Panicum coloratum cv. Klein Verde (Pc) collected from plants grown in an alkaline-sodic soil (pH = 9.8, ECe = 0.69 dS m-1, EPS = 26.2%). To compare G of both species, 50 caryopses (n = 5) were incubated in deionized water. To evaluate G responses to salinity and alkalinity, an experiment with completely randomized design and factorial structure (n = 4) of two species x four concentrations of Na+-salts (25, 50, 100 and 150 mM) x two pHs (6 and 10) was performed. Treatments consisted in combinations 1:1 of NaCl + SO4Na (pH = 6) and Na2CO3 + NaHCO3 (pH = 10): 25mMpH6 (control); 25mM-pH10; 50mM-pH6; 50 mM-pH10; 100mM-pH6; 100mM-pH10; 150mM-pH6 and 150mMpH10. Samples of the natural-dispersal material from panicles of Cg and Pc contained (mean ± SEM; % of total weight): caryopses covered by glumes (53 ± 2.6; 41.3 ± 4.6), isolated caryopses (1.4 ± 0.6; 10.3 ± 1.95), empty caryopses (32.9 ± 2.4; 22.7 ± 2.4) and inert materials (12.5 ± 2.2; 25.7 ± 2.1). Caryopses of Cg and Pc incubated in water showed similar values (mean ± SEM, in %) of G (96.5 ± 2.4 and 89.2 ± 3.6) and GV (54.7 ± 7and 51.7 ± 5.5). In the presence of salt 25 mM, the increment of pH from 6 to 10 did not inhibit G of Cg (94.4 ± 2.55 and 90.7 ± 3.7) or Pc (93.9 ± 2.2 and 92.95 ± 1.9). Incubation in 50mM-pH=10 inhibited G of Pc (33.2 ± 4.7) but not G of Cg (93.5 ± 3.3). The solution 100mM-pH=10 inhibited more the germination of Pc (2.5 ± 1.5) than that of Cg (66.35 ± 5.5), and 150mM-pH10 strongly inhibited germination of both species, Cg (3.5 ± 1.5) and Pc (0 ± 0). In solutions with pH = 6, the G of Cg and Pc was not affected up to 100 mM of salt, but 150 mM inuduced decreases of 25 % and 20 % of G, respectively, in relation to that observed in 25mM-pH=6. The increment of pH also affected more GV of Pc than that of Cg. GV of both species responded in a similar way to increases of salinity in neutral (pH = 6) solutions. The GV of the caryopses incubated in 50mM-pH=6 did not differ from their respective controls. From 50 mM, each increase of salt concentration induced the decrease of
GV of both species, relative to their respective controls.
Keywords: salinity, alkalinity, megathermic forage poaceae, germination velocity.
1Universidad Nacional de Lomas de Zamora, Facultad de Ciencias Agrarias, Ruta 4 km 2 (1836) Llavallol, Buenos Aires, Argentina.
2Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria (EEA) Cuenca del Salado, (7130) Chascomús,
Buenos Aires, Argentina. Correo electrónico: firstname.lastname@example.org