No abstract

Maize (Zea mays L.) or Indian wheat is the most cultivated cereal in the world and the first in terms of quantity before wheat. Its cultivation is confronted with the climate change which causes drought, and this last one reduces considerably its production. The objective of this experiment is to select maize (Zea mays L.) varieties resistant to water stress using gamma irradiation. Its aim is to characterize agromorphologically two maize lines derived from the gamma irradiated variety EV8728. This study took place in Daloa (Ivory Coast). The plant material consisted of maize plants obtained by self-fertilization after five cycles from seeds of the variety EV8728 irradiated with gamma rays at a dose of 300 grays. Observations and measurements were made on the number and area of leaves, height and diameter of maize plants, male and female flowering parameters (date of panicle appearance, pollen grains, cob and silks) and number of spikelets, cob insertion height (CIE), panicle height and internode length. At the 58th das, the highest number of leaves (18.76) was observed in the plants of line 36 watered at capacity in field S0. On the other hand, the number of leaves (16.04) was lowest on the plants of the same line under severe stress (S2). Regardless of the type of stress applied, the plants of the control EV8728 always dominate, while the most stunted are those of the line L36. The date of panicle appearance (DAP) was early with the EV8728 control compared to the tested lines (L36 and L71), while the date of pollen appearance (DAGP) was about 4 d after the panicle was visible. Under moderate stress, a delay in flowering (anthesis) is observed in EV8728 and line L71 while there is no change in date for line L36.

This study aims to assess the physico-chemical quality of irrigation water and soil in the irrigated area of M'Bahiakro. Seasonal campaigns to measure in situ the physical parameters (pH, temperature, salinity, electrical conductivity and total dissolved solids) of the N'Zi River were carried out, followed by sampling (water and soil) for chemical analyses. The physico-chemical quality of irrigation water was assessed on the basis of four (4) parameters, namely Dry Residue (SR), Osmotic Pressure (π), Kelly's Coefficient (KC), Sodium Absorption Rate (SAR) and Wilcox Diagram. In terms of soil quality, the parameters (pH, N, P, P, K, MO, CEC and ESP) were determined. Overall, the results show a good physical-chemical quality of the irrigation water and soil. Indeed, the irrigation waters studied show good physico-chemistry and low to medium salinity depending on the seasons of the year. As for the soils, they have a clayey-silt texture, a slightly acidic pH, favourable to rice cultivation and a good organic matter content, which best maintains an active microbial life. In addition, the major elements (nitrogen, phosphorus and potassium) present in irrigation water and soils could be enough to optimize the yield of rice cultivation. These results then lead to the conclusion that the irrigation water from the N'Zi River and the soils of the irrigated perimeter of M'Bahiakro are naturally suitable for agricultural use, particularly for rice cultivation. As a result, an additional supply of fertilizer (NPK) would not necessarily be necessary during the exploitation phase of the rice area.

The use of well water by disadvantaged populations in most African cities often presents health risks. The purpose of this study is to determine the physico-chemical and microbiological quality of M'bahiakro well water. A series of physico-chemical, microbiological and piezometric analyses were carried out on the well water in the area. The results of these analyses were processed using Piper and Schoeller-Berkaloff diagrams and the software R 3.1.2 for Principal Component Analysis. Physico-chemical analysis results show that the water has an average temperature of 28˚C. They are acidic, with a pH that generally varies from 4 to 6. M'bahiakro well waters are highly mineralized, with an average electrical conductivity of 369.1 μS/cm and 984.1 µS/cm and pass from sodium and potassium chlorinated facies in the dry season (February) to sodium chlorinated facies in the rainy season (October) with K + , Na + and NO − 3 ions dominating. These ions would be the result of soil rainfall and the intervention of anthropogenic activities in the pollution of shallow groundwater. Bacteriological results exploitation shows that the well waters studied host high densities of enteritis bacteria (E. coli, Fecal streptococcus, and Clostridium perfringens) during the rainy period (October). M'Bahiakro's well water is of poor quality and unsuitable for human consumption without prior treatment. However, they deserve particular attention and would require further treatment in rainy periods.