Genotypic variation between maize (Zea mays L.) single cross hybrids in response to drought stress

Abstract

Effects of soil drought on growth and productivity of 16 single cross maize hybrids were investigated under field and greenhouse experiments. The Drought Susceptibility Index (DSI) was evaluated in a three year field experiment by the determination of grain loss in conditions of two soil moisture levels (drought and irrigated) and in a pot experiment by the effects of periodical soil drought on seedling dry matter. In the greenhouse experiment response to drought in maize genotypes was also evaluated by root to shoot dry mater ratio, transpiration productivity index, indexes of kernel germination and index of leaf injury by drought and heat temperature. The obtained values of DSI enabled the ranking of the tested genotypes with respect to their drought tolerance. The values of DSI obtained in the field experiment allow to divide the examined genotypes into three, and in the greenhouse experiment into two groups of drought susceptibility. The correlation coefficients between the DSI of maize hybrids in the field and the greenhouse experiments was high and statistically significant, being equal to 0.876. The ranking of hybrids drought tolerance, identified on the basis of field experiments was generally in agreement with the ranking established on the basis of the greenhouse experiment. In the greenhouse experiment statistically significant coefficients of correlation with DSI values in hybrids were obtained for the ratio of dry matter of overground parts to dry matter of roots, both for control and drought treatments, whereas in the estimation of the transpiration productivity coefficient and total dry matter the correlation coefficients were not statistically significant. In this study several laboratory tests were carried out for the drought tolerance of plants (kernel germination, leaf injury) on 4 drought resistant and 4 drought sensitive maize hybrids. Statistically significant correlation coefficients between DSI and the examined parameter of grain germination and leaf injury were obtained for the determination of promptness index (PI), seedling survival index (SS) and leaf injuries indexes (IDS, ITS) as a result of exposure to 14 days of soil drought, osmotic drought-0.9 MPa and exposure to high temperature 45 ° or 50 °C. The results of laboratory tests show that in maize the genetic variation in the degree of drought tolerance is better manifested under severe conditions of water deficit in the soil.List of abbreviations: G D D , growth degree days; K, h y d r o t h e r m i c index; DSI, drought susceptibility index; D, drought plot; IR, irrigated plot, F W C , field water capacity; FG, final grain germination; PI, promptness index; SS, seedling survival index; IDS, conductivity m e a s u r e m e n t s in seedling leaves exposed to drought; ITS, conductivity measurements in seedling leaves exposed to high tempera-

Effects of Sowing Date on Physiological Characteristics, Yield and Yield Components for Different Maize (Zea mays L.) Hybrids

“…The International Maize and Wheat Improvement Centre (CIMMYT) accompany with National Agricultural Research Systems (NARS) routinely conducted maize regional trials with the objective of evaluating, selecting high yielding and stable genotypes in a wide range of environments (Banziger and De Meyer, 2002). Grzesiak (2001) reported remarkable genotypic variability among corn varieties for several characteristics. Ihsan et al (2005) also demonstrated considerable genetic differences for morphological variables for corn genotypes.…”

Cluster and Principal Component Analysis in Maize

“…This emphasis is likely to ensure still higher growth rates in productivity of this versatile crop in the years to come. There is still a considerable scope to improve productivity and adaptability by breeding heterotic hybrids (Grzesiak, 2001). The success of any breeding method depends on the availability of genetic diversity in the base population.…”

Efficacy of seed priming techniques on performance of maize hybrids in Multan

“…Genetic development in traits shows economic significance along with maintaining adequate amount of variability is always the objective in maize breeding programs (Hallauer et al, 1973). Grzesiak (2001) observed significant genotypic inconsistency among various maize genotypes for diverse characters. Ihsan et al (2005) reported momentous genetic variability for morphological parameter for maize genotypes.…”