Răsărirea plantulelor de porumb în semănatul timpuriu
2016
Ştirbu, V. (Institute of Crop Production “Porumbeni”, Pascani, Criuleni (Republic of Moldova) | Partas, E. | Spânu, A.
The experiments were performed in 2013-2015 on 11 commercial maize hybrids of medium and semi-late maturity, planted on the 1st, 8th, 15th and 22nd of April which is by 4, 3, 2 and 1 week earlier than the optimumsowing date recommended for the central zone of the Republic of Moldova – April 29 (control variant). The studyalso included a variant which was sown at a late date (May 6). The hybrids sown on earlier dates exhibited a lowerseedling emergence rate (on average over the all testing years) than the control: 8-11% less in the variants sownin the first two weeks of April and 5% less in the variants sown in the third or fourth week of April). The naturalbackground during the germination and emergence period allowed to sort the hybrids, only in some cases, bytheir tolerance to sub-optimal temperatures. The hybrids PR37F73, POR 461, POR 310 and POR 427 in somevariants with early sowing date recorded an emergence rate close or equal to the control variant, which meansthat these hybrids have shown a higher degree of tolerance to low temperatures during the period of germdevelopment. In a statistical complex of three factors the influence of planting dates, hybrid and testing year onthe variability of the number of emerged seedlings were analyzed. Out of these factors, the genotype and testingyear were more important than the planting dates. The period between seed sowing and seedling emergence(ranging from 24 to 28 days in the variant sown in April 1 and from 8 to 13 days in the control variant and in thevariant sown in May 6) is closely correlated with the number of days with sub-optimal night temperatures, thefirst days after sowing being critical for plantlet development.
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