Effects of seed vigour on field emergence and early seedling growth of maize under arid tropical conditions.

摘要

A field emergence (FE) experiment was carried out in a farm practicing oasis agriculture under arid conditions in Djibouti, using 3 seed lots ('Koshu 1', 'Koshu 2' and 'Shiro') of maize. The objectives of the experiment were to evaluate to what extent treatments including stone mulching (SM) or pre-soaking (PS) and both treatments (SM+PS) affected FE and early seedling growth (ESG), and to determine the effects of vigour differences between the 3 seed lots on FE and ESG. Although the SM or/and PS treatments increased the speed of FE and ESG significantly, they did not affect the FE percentage at 9 days after sowing (DAS). Results of the germination test indicated that the 3 seed lots displayed the same level of germination capacity. However, although the vigour tests used in the present study might include variables influencing the results, it was considered that there were differences in seed vigour between the 3 seed lots, i.e. vigour of 'Shiro' was lower than that of 'Koshu 1' and 'Koshu 2'. The percentage of FE of maize at 9 DAS in the high vigour lots ('Koshu 1' and 'Koshu 2') was significantly higher than that in the low vigour lot ('Shiro') in all the treatments. In the seed lots with high vigour, the speed of FE increased with the SM, PS and SM+PS treatments to a higher extent than in the seed lot with low vigour. These results suggested that the use of seed lots with high vigour may decrease the number of vacant hills and contribute to the increase of the productivity of maize in oasis farms.