Genotypic variation between maize (Zea mays L.) single cross hybrids in response to drought stress |
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Authors: | Stanisław Grzesiak |
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Institution: | (1) Laboratory of Plant Growth and Development, The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Podluzna street no 3 (Lab. “Phytotron”), PL 30-239 Cracow, Poland |
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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. |
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Keywords: | Maize hybrids Drought susceptibility index Germination Leaf injury |
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