- David Montcho1,2*, Koichi Futakuchi1, Gustave Djedatin3, Mamadou Fofana4, Baboucarr Manneh5, Clement Agbangla2, Corneille Ahanhanzo2
- Physiology Unit, Africa Rice Center, Cotonou, Benin
- Department of Genetic and Biotechnology, University of Abomey-Calavi, Cotonou, Benin
- Department of Genetic, Polytechnic University of Abomey, Dassa, Benin
- Physiology Unit Africa Rice Center Ibadan, Nigeria
- Irrigated Rice Breeding Unit, Africa Rice Center, Sahel Station Saint Louis Senegal
In rainfed rice cultivation, weeds, low or no fertiliser inputs and no
water control can be production constraints. Vegetative early vigor may
favour weed competitiveness. Since Oryza glaberrima is considered as
genetic resources for this characteristic, growth analyses of three
lines were made from seeds to juvenile plants of 35 days after seed
soaking (DAS) in a pot experiment with two O. sativa under two soil
water regimes: soil of water saturation without standing water (SAT) and
soil of a wet surface without water saturation (WET).
After germination,
total dry weigh decreased (heterotrophic phase using carbohydrate
reserve in kernels) then increased during autotrophic phase. Start of
autotrophic phase was earlier in SAT than in WET (6.2 vs 7.6 DAS) and
kernel weight lost was also higher in SAT (93 vs 82 %). Total dry weight
was smaller in SAT than in WET at 5 DAS but larger at and after 11 DAS.
The carbohydrate reserve in kernels was more rapidly and sufficiently
used for seedling growth in SAT than in WET; the growth phase more
quickly shifted from the hetero trophic to auto trophic in SAT than in
WET then growth after the sift was better in SAT. Leaf area (determined
at and after 13 DAS) was always larger in SAT than in WET. Varietal
difference in total dry weight became significant (P<0.05) at 28 DAS;
the O. glaberrima lines showed larger total dry weight than O. sativa
varieties and difference between the two species was more obvious in SAT.
