Enayat Rezvani Khorshidi; Farshid Hasani; Mohammad Reza SHiri; Mehran Sharafizadeh; Aziz Moradi; Mohammad Rahmani; Aidin Hamidi; Mostafa Arabi
Abstract
In order to study the effect of seed size of hybrid maize (KSC704) at different sowing times on the indices related to percentage, rate, vigor and uniformity of seed emergence in the field, an experiment was conducted in two years 2012 and 2013 as a factorial design in Karaj. The female rows (B73 inbred ...
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In order to study the effect of seed size of hybrid maize (KSC704) at different sowing times on the indices related to percentage, rate, vigor and uniformity of seed emergence in the field, an experiment was conducted in two years 2012 and 2013 as a factorial design in Karaj. The female rows (B73 inbred line) were pollinated by male rows (Mo17 inbred line) in each plot. After different seed were determined, they cultivated in the field in the next year. Medium seeds in the first year and flat seeds in the second year had significantly the highest field emergence percentages nad round seeds had the lowest in both years. Flat seeds produced seedlings with the highest dry weight in both years. But in the aspect of emergence uniformity of seedling, medium seeds had a higher uniformity than the others. Despite the superiority of flat seeds in some indices, its superiority was not a definite issue, and in some of the important emergence indices, medium and even the round size had better field performance, depending on the environmental conditions of growth and development of the seeds on the ears of mother plant and at sowing time, and the compression of the seeds in different points of the ear, as well as desired purpose of cultivation. If vigorous seedlings are needed, the flat seeds, but if a higher emergence rate and uniformity is desired, the medium seeds and even round seeds can be better suited
E. Rezvani; F. Ghaderifar; A. Hamidi; E. Soltani
Volume 5, Issue 2 , January 2016, , Pages 51-63
Abstract
In order to study the effect of desiccation tolerance on seed germination and vigor of hybrid maize, a field experiment was conducted using five sowing dates in three replications. Experiments were conducted in a completely randomized design in Karaj, Iran. Sampling from female rows (B73 Inbred line) ...
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In order to study the effect of desiccation tolerance on seed germination and vigor of hybrid maize, a field experiment was conducted using five sowing dates in three replications. Experiments were conducted in a completely randomized design in Karaj, Iran. Sampling from female rows (B73 Inbred line) was started right after pollination in a weekly scale. The harvested hybrid seeds were dried in open air conditions. Changes in seed growth and development were evaluated from 20 days after flowering and laboratory tests were performed on fresh and dried seed samples of each developmental stages. The results showed that the effects of sowing dates on normal seedling percentage, mean germination time) and seedling length was significant. The 4th sowing date had the highest normal seedling and seed vigor. Seed filling rate (3.7-9.2 mg/gram) and moisture content reduction (0.63 -1.06 percent/day) was different, depends on the sowing date and temperature of seed developmental period. It is observed that the developing seeds that dried before standard germination test, started to germinate very sooner (20-30 DAF on basis of sowing date) than fresh seeds (that start 30-50 DAF). Dried seeds reached meaningfully sooner to the highest normal seedlings percentage (30-60 DAF). When the desiccation started without hot temperature stress in third and fourth sowing dates, desiccation tolerance completed sooner. So the seeds reach to the highest percentage of normal seedling very soon, after drying. The evaluation of mean germination time and seedling length, as indicators of seed vigor showed that dried seeds reach to maximum germination rate and seedling length sooner than fresh seeds. The changes trend in these indicators was similar to changes in normal seedling percentage. It was concluded that appropriate temperature (lower than 35ºC) in desiccation period, especially at the beginning stages, results in fast extension of desiccation tolerance among the seeds and enhancing the seed quality after drying.
