NaCl tolerance in maize (Zea mays ssp. mays) x Tripsacum dactyloides L. hybrid calli in regenerated plants

Abstract

Since corn has been classified as one of the most sensitive crops to soil salinity, the evaluation of NaCl toleranceof a hybrid of Zea mays ssp. mays (2n=40) and Tripsacum dactyloides (2n=72), was considered of interest to determinethe possibility of using this germplasm in corn tolerance improvement. Long-term organogenic calli, obtainedfrom immature hybrid embryos, have shown high rates of multiplication and plant regeneration. After in vitro treatmentof these calli with different levels of salinity, the survival and regeneration percentages and the daily relativeweight increments were calculated. Regenerated plants were transplanted to pots and watered with NaCl solution (6.1dS m-1) in order to assess tolerance at a whole plant level. Measurements of height, number of leaves per plant, andfresh and dry weights were taken. Exposure to 170 mM NaCl in vitro during 35 days and in vivo during 20 days produceda fresh weight decrease of 51% in calli and 31% in plants, respectively. These results indicate an improved toleranceof the maize/Tripsacum hybrid to salinity stress, in vitro and in vivo, compared with results from previous reportsusing other corn genotypes under similar conditions.

Meiotic study of Zea mays ssp. mays (2n = 40) x Tripsacum dactyloides (2 n = 72) hybrid and its progeny

“…Half of the plants showed an annual cycle and the rest were biannual or perennial ones. Further, tolerance to low temperatures and NaCl salinity was observed in these plants (Pesqueira et al 2003;Jatimliansky et al 2004). Pollen fertility ranged from 0% (most of the plants) to 50%.…”

“…Maize x T. dactyloides F1 hybrid plants are sexually sterile, but low percentages of viable seeds have been obtained mainly by apomixis (Leblanc et al 1995a;Sokolov et al 2000). Regenerated hybrid plants showed salinity tolerance (Pesqueira et al 2003). Further, F1 hybrid plants grown under field conditions or culture chambers showed high tolerance to low temperatures (-2ºC and 5ºC, respectively), although maize and Tripsacum showed great susceptibility under the same conditions (Jatimliansky et al 2004).…”

Impacts of Salt Water Intrusion on Maize (Zea mays) and Rice (Oryza sativa) Production under Climate Change Scenarios in Bagamoyo District-Tanzania

“…It is obvious that salinity is affecting Zea mays production in Bagamoyo as it was clearly reported by farmers (See Figure 9). Zea mays is sensitively affected by salinity [38], because salt reduces available water in the soil for the plant uptake and blocks the permeability of its root cortex hence death of the crop. This implies that, if no proper measurements taken immediately to overcome this problem, then there will be a huge Zea mays loss in Bagamoyo and other coastal zones with SWI effects.…”

NaCl effects in Zea mays L. x Tripsacum dactyloides (L.) L. hybrid calli and plants

“…Long-term organogenic calli have been obtained from tetraploid maize (2n = 40) x Tripsacum dactyloides (2n = 72) hybrid embryos. Regenerated hybrid plants showed a somatic chromosome number 2n = 56 (García et al 2000) and high tolerance to salinity (Pesqueira et al 2003) and low temperatures (Jatimliansky et al 2004). Even though maize x T. dactyloides F1 hybrid plants exhibit very low fertility, a few viable seeds have been obtained (Leblanc et al 1995;Sokolov et al 2000;Molina et al 2005).…”