Identification of Mexican Maize Races (Zea mays L.) with Drought Tolerance using Osmotic Potential Experiments for Genetic Breeding

J.A. Batista-Rascon¹, J.C. Jiménez-Galindo²*, N. Ramírez-Cabral³, G. Castellanos-Pérez¹ and J.J. Figueroa-Gonzalez³

¹Autonomous University of Chihuahua, Agrotechnological Sciences Faculty, V. Carranza y Escorza s/n, Col. Centro, Chihuahua, 31000 Chihuahua, México
²Agriculture and Livestock Research, National Institute of Forestry, Av. Hidalgo No 1213, Cuauhtémoc, 31500 Chihuahua, México
³National Institute of Forestry, Agriculture and Livestock Research, Km. 24.5 Carretera Zacatecas-Fresnillo Calera de Víctor Rosales, Zacatecas. C.P. 98500, México
*Correspondence: cruz2477@yahoo.com.mx

Abstract:

Maize (Zea mays L.) is the third most important cereal crop worldwide after wheat and rice per cultivated area with 249,225,876 hectares and the most important crop for number of harvested grain tons with 1,482,997,259 in 2021. Some native Mexican maize races could be a source for drought tolerance to improve commercial cultivars and hybrids. The experiments were conducted using various osmotic pressures (OP) induced by polyethylene glycol (PEG-6000) (0, -0.05, -0.15, -0.30 and -0.49 MPa) simulating an increase of drought stress in ten maize genotypes. The main objectives of this study were the evaluation of germination and seedling growth components in response to drought stress and the identification of sources of drought tolerance in Mexican maize races. Apachito-r showed an increased germination in 110.4%, Cristalino-079 had a decreased germination in 98.7% and Cristalino-279 reduced its germination in a 91.1% compared to the control. Apachito-r outstands in root length at -0.05 OP increasing 200.1% and at -0.49 increasing 129.8%. The values for stem length were decreasing as the OP was increasing and only Apachito-r showed a significant difference at -0.30 MPa decreasing 39.8% respect to its control. Cristalino-279 showed significant difference in the variable root fresh weight and its value outstand at -0.15 increasing 267.2%, at -0.30 increasing 281.6% and at -0.49 MPa increasing 189.3% compared to the control in water. The variable root dry weight had the highest value for Apachito-r at -0.05 MPa increasing in a 189.4%, decreasing at -0.15 in 72% and at -0.30 MPa in a 79.8% and increasing at -0.49 MPa in 112.3%. Also noteworthy are E-zapata-r increasing 190.5% and Cristalino-061 increasing 142.9% at -0.30. E-zapata-r at -0.49 increased 115.1%. Cristalino-279 showed significant difference in the variable stem fresh weight and its value outstand at -0.05, -0.15 and -0.30 MPa increasing 146.7%, 103.7% and 60.2% respectively. Finally, in stem dry weight the tendency was to decrease as OP was increasing, however Cristalino-279 showed differences at -0.30 decreasing in 89.5% and at -0.49 MPa increasing in a 143.5% respect to the control. The most drought tolerant genotypes were Cristalino-279, Apachito-r, Azul and 8-carreras-PP. The most tolerant genotypes showed greater root length, greater root fresh and dry weight, better germination and greater stem length. Resistant and susceptible genotypes are ideal material to understand the physical and chemical mechanisms related to drought tolerance. Cristalino-279 shows the best level of drought tolerance at all levels of osmotic pressure, this genotype can be used as a source of drought tolerance for the improvement of commercial maize.

Key words:

drought tolerance, native maize races, osmotic pressure, polyethylene glycol

Osmotic stress tolerance in forage oat varieties (Avena Sativa L.) based on osmotic potential trials

A. Ortega-Ortega¹*, J.C. Jiménez-Galindo²*, R.Á. Parra-Quezada¹, J.L. Jacobo-Cuellar¹, Teresita D. J. Ruiz-Anchondo¹, J.J. Salmerón-Zamora¹, P.B. Zamudio-Flores³ and R.A. Malvar⁴

¹Autonomous University of Chihuahua, Agrotechnological Sciences Faculty, V. Carranza y Escorza s/n, Col. Centro, Chihuahua, 31000 Chihuahua, México
²National Institute of Forestry, Agriculture and Livestock Research, Av. Hidalgo No 1213, Cuauhtémoc, 31500 Chihuahua, México
³Research Center in Food and Development, A.C., Cuauhtemoc Unit, Av. Rio conchos s/n, Parque Industrial, Apartado Postal 781, Cuauhtemoc, 31570 Chihuahua, Mexico
⁴Misión Biológica de Galicia, Spanish National Research Council (CSIC), Apartado 28, 36080 Pontevedra, Spain
*Correspondence: capacitadorortega.arraigate@gmail.com; cruz2477@yahoo.com.mx

Abstract:

Forage oats (Avena sativa L.) are globally important for milk and meat production, and, to a lesser extent, for the human diet. In Mexico, oats are a strategic crop, occupying the fourth place in cultivated area, only after maize for grain, bean, and sorghum for grain. Droughts are the main problem for oat production in Mexico. This study evaluated the germination and seedling growth of several oat varieties in response to drought stress simulated by PEG-6000 treatments of different osmotic pressure in order to identify drought-resistant genotypes. The Teporaca genotype was the most outstanding in the three levels of OP compared to its control with 0.0 of Osmotic Potential (OP). The Teporaca genotype showed the largest root length and the lowest diminishment of root length under osmotic stress conditions. This genotype also had the largest shoot length in the three osmotic stress levels. Regarding root fresh weight, Babicora stands out with 98.5% and Teporaca with 43% in the most severe level. Teporaca, Menonita, and Babicora showed the outstanding root dry weights of 346.5%, 327.2%, and 251.2%, respectively. These varieties had higher root dry weight than their own controls in water in the most severe level of OP. In conclusion, the Teporaca, Menonita, and Karma genotypes showed the highest osmotic stress tolerance and could be used as sources of favorable alleles to improve oat drought tolerance.

Key words: